HART 6.1 Application Guide

Application Guide

Keep Your Plant Competitive

Get More from What You’ve Got

Unleash the Power – See What You Can Do

Realize the Potential

Unleash the Power – Your Wish is HART’s Command

Unleash The Power - HART May be All the Fieldbus You Really Need

WirelessHART™ Information Unchained

WirelessHART Overview Presentation by HCF Executive Director Ron Helson and HCF Chief Engineer Wally Pratt to ISA SP100 Committee on 22 May 2007. Recorded - Slides and Audio

The Complete HART Guide Sponsors

http://www.abb.com

http://www.emersonprocess.com

http://www.fluke.com

http://www.mactekcorp.com

http://www.meriam.com

http://support.automation.siemens.com

http://www.yokogawa.com

© 2005 HART Communication Foundation

Copyright © 1999-2005 HART Communication Foundation. All rights reserved.

HART® is a registered trademark of the HART Communication Foundation. Any use of the word “HART” hereafter in this document implies the registered trademark. All other trademarks used in this document are acknowledged to be trademarks of their respective companies.

For additional information contact:HART Communication Foundation9390 Research BoulevardSuite I-350Austin, Texas 78759 USATel: 512-794-0369Fax: 512-794-3904

HART APPLICATION GUIDE

PrefaceIn today’s competitive environment, all companies seek to reduce operation costs, deliver products rapidly, and improve product quality. The HART® (highway addressable remote transducer) protocol directly contributes to these business goals by providing cost savings in:

Commissioning and installationPlant operations and improved qualityMaintenance

The HART Application Guide has been created by the HART Communication Foundation (HCF) to provide users of HART products with the information necessary to obtain the full benefits of HART digital instrumentation. The HART communication protocol is an open standard owned by the more than 100 member companies in the HCF. Products that use the HART protocol to provide both analog 4–20 mA and digital signals provide flexibility not available with any other communication technology.

The following four sections provide you with an understanding of how the HART technology works, insight on how to apply various features of the technology, and specific examples of applications implemented by HART protocol users around the world:

Theory of Operation3Benefits of HART CommunicationsGetting the Most out of HART SystemsIndustry Applications

© 2003 HART Communication Foundation Page 1

THEORY OF OPERATION

Theory of OperationThe following sections explain the basic principles behind the operation of HART instruments and networks:

Communication ModesFrequency Shift KeyingHART NetworksHART Commands

Page 2 © 2003 HART Communication Foundation

THEORY OF OPERATION

Communication ModesMASTER-SLAVE MODE

HART is a master-slave communication protocol, which means that during normal operation, each slave (field device) communication is initiated by a master communication device. Two masters can connect to each HART loop. The primary master is generally a distributed control system (DCS), programmable logic controller (PLC), or a personal computer (PC). The secondary master can be a handheld terminal or another PC. Slave devices include transmitters, actuators, and controllers that respond to commands from the primary or secondary master.

BURST MODE Some HART devices support the optional burst communication mode. Burst mode enables faster communication (3–4 data updates per second). In burst mode, the master instructs the slave device to continuously broadcast a standard HART reply message (e.g., the value of the process variable). The master receives the message at the higher rate until it instructs the slave to stop bursting.

Use burst mode to enable more than one passive HART device to listen to communications on the HART loop.


THEORY OF OPERATION

Frequency Shift KeyingThe HART communication protocol is based on the Bell 202 telephone communication standard and operates using the frequency shift keying (FSK) principle. The digital signal is made up of two frequencies— 1,200 Hz and 2,200 Hz representing bits 1 and 0, respectively. Sine waves of these two frequencies are superimposed on the direct current (dc) analog signal cables to provide simultaneous analog and digital communications (Figure 1). Because the average value of the FSK signal is always zero, the 4–20 mA analog signal is not affected. The digital communication signal has a response time of approximately 2–3 data updates per second without interrupting the analog signal. A minimum loop impedance of 230 Ω is required for communication.

Figure 1: Simultaneous Analog and Digital Communication

“1” “0”“1” “1”

“1” “1”

“0”“0”

“0”

Time

20 mA

4 mA

Digital Signal

Analog Signal

Note: Drawing not to scale.


THEORY OF OPERATION

HART NetworksHART devices can operate in one of two network configurations—point to point or multidrop.

POINT-TO-POINT In point-to-point mode, the traditional 4–20 mA signal is used to communicate one process variable, while additional process variables, configuration parameters, and other device data are transferred digitally using the HART protocol (Figure 2). The 4–20 mA analog signal is not affected by the HART signal and can be used for control in the normal way. The HART communication digital signal gives access to secondary variables and other data that can be used for operations, commissioning, maintenance, and diagnostic purposes.

Figure 2: Point-to-Point Mode of Operation

Control System or Other Host Application

Multiplexer

Barrier

Handheld Terminal

Field Device

Note: Instrument power is provided by an interface or external power source that is not shown.


HART Networks

THEORY OF OPERATION

MULTIDROP The multidrop mode of operation requires only a single pair of wires and, if applicable, safety barriers and an auxiliary power supply for up to 15 field devices (Figure 3). All process values are transmitted digitally. In multidrop mode, all field device polling addresses are >0, and the current through each device is fixed to a minimum value (typically 4 mA).

Figure 3: Multidrop Mode of Operation

Use multidrop connection for supervisory control installations that are widely spaced, such as

pipelines, custody transfer stations, and tank farms.

Input/Output (I/O) System

Handheld Terminal

Field Devices

Control System or Other Host Application

Note: Instrument power is provided by an interface or external power source that is not shown.


THEORY OF OPERATION

HART CommandsThe HART command set provides uniform and consistent communication for all field devices. The command set includes three classes: universal, common practice, and device specific (Table 1). Host applications may implement any of the necessary commands for a particular application.

UNIVERSAL All devices using the HART protocol must recognize and support the universal commands. Universal commands provide access to information useful in normal operations (e.g., read primary variable and units).

COMMON PRACTICE

Common practice commands provide functions implemented by many, but not necessarily all, HART communication devices.

DEVICE SPECIFIC Device-specific commands represent functions that are unique to each field device. These commands access setup and calibration information, as well as information about the construction of the device. Information on device-specific commands is available from device manufacturers.

SUMMARY TABLE

Note: Table 1 is a partial list of HART commands. See Appendices B, C, and D for more detailed information.

Universal Commands Common Practice Commands Device-Specific Commands

• Read manufacturer and device type

• Read primary variable (PV) and units

• Read current output and percent of range

• Read up to four predefined dynamic variables

• Read or write eight-character tag, 16-character descriptor, date

• Read or write 32-character message

• Read device range values, units, and damping time constant

• Read or write final assembly number

• Write polling address

• Read selection of up to four dynamic variables

• Write damping time constant• Write device range values• Calibrate (set zero, set span)• Set fixed output current• Perform self-test• Perform master reset• Trim PV zero• Write PV unit• Trim DAC zero and gain• Write transfer function (square

root/linear)• Write sensor serial number• Read or write dynamic variable

assignments

• Read or write low-flow cut-off• Start, stop, or clear totalizer• Read or write density calibration

factor• Choose PV (mass, flow, or

density)• Read or write materials or

construction information• Trim sensor calibration• PID enable• Write PID setpoint• Valve characterization• Valve setpoint• Travel limits• User units• Local display information

Table 1: HART Commands


HART Commands

THEORY OF OPERATION

ESTABLISHING COMMUNICATION WITH A HART DEVICE

Each HART device has a 38-bit address that consists of the manufacturer ID code, device type code, and device-unique identifier. A unique address is encoded in each device at the time of manufacture. A HART master must know the address of a field device in order to communicate successfully with it. A master can learn the address of a slave device by issuing one of two commands that cause the slave device to respond with its address:

Command 0, Read Unique Identifier—Command 0 is the preferred method for initiating communication with a slave device because it enables a master to learn the address of each slave device without user interaction. Each polling address (0–15) is probed to learn the unique address for each device.Command 11, Read Unique Identifier by Tag - Command 11 is useful if there are more than 15 devices in the network or if the network devices were not configured with unique polling addresses. (Multidropping more than 15 devices is possible when the devices are individually powered and isolated.) Command 11 requires the user to specify the tag numbers to be polled.

DEVICE DESCRIPTION

Some HART host applications use device descriptions (DD) to obtain information about the variables and functions contained in a HART field device. The DD includes all of the information needed by a host application to fully communicate with the field device. HART Device Description Language (DDL) is used to write the DD, that combines all of the information needed by the host application into a single structured file. The DD identifies which common practice commands are supported as well as the format and structure of all device-specific commands.

A DD for a HART field device is roughly equivalent to a printer driver for a computer. DDs eliminate the need for host suppliers to develop and support custom interfaces and drivers. A DD provides a picture of all parameters and functions of a device in a standardized language. HART suppliers have the option of supplying a DD for their HART field product. If they choose to supply one, the DD will provide information for a DD-enabled host application to read and write data according to each device’s procedures.

DD source files for HART devices resemble files written in the C programming language. DD files are submitted to the HCF for registration in the HCF DD Library. Quality checks are performed on each DD submitted to ensure specification compliance, to verify that there are no conflicts with DDs already registered, and to verify operation with standard HART hosts. The HCF DD Library is the central location for management and distribution of all HART DDs to facilitate use in host applications such as PCs and handheld terminals.

Additional information, not provided by the DD, may be required by some host applications for screen formatting and other uses.


BENEFITS OF HART COMMUNICATIONS

Benefits of HART CommunicationsThe HART protocol is a powerful communication technology used to exploit the full potential of digital field devices. Preserving the traditional 4–20 mA signal, the HART protocol extends system capabilities for two-way digital communication with smart field instruments.

The HART protocol offers the best solution for smart field device communications and has the widest base of support of any field device protocol worldwide. More instruments are available with the HART protocol than any other digital communications technology. Almost any process application can be addressed by one of the products offered by HART instrument suppliers.

Unlike other digital communication technologies, the HART protocol provides a unique communication solution that is backward compatible with the installed base of instrumentation in use today. This backward compatibility ensures that investments in existing cabling and current control strategies will remain secure well into the future.

Benefits outlined in this section include:Improved plant operationsOperational flexibilityInstrumentation investment protectionDigital communication



Improved Plant OperationsThe HART protocol improves plant performance and increases efficiencies in :

Commissioning and installationPlant operations Maintenance

COST SAVINGS IN COMMISSIONING

HART-based field devices can be installed and commissioned in a fraction of the time required for a traditional analog-only system. Operators who use HART digital communications can easily identify a field device by its tag and verify that operational parameters are correct. Configurations of similar devices can be copied to streamline the commissioning process. A loop integrity check is readily accomplished by commanding the field transmitter to set the analog output to a preset value.

COST SAVINGS IN INSTALLATION

The HART protocol supports the networking of several devices on a single twisted wire pair. This configuration can provide significant savings in wiring, especially for applications such as tank monitoring.

Multivariable devices reduce the number of instruments, wiring, spare parts, and terminations required. Some HART field instruments embed PID control, which eliminates the need for a separate controller, and results in significant wiring and equipment cost savings.

Use HART multidrop mode to connect multiple instruments to a single cable and reduce installation costs.


Improved Plant Operations


IMPROVED MEASUREMENT QUALITY

HART-communicating devices provide accurate information that helps improve the efficiency of plant operations. During normal operation, device operational values can be easily monitored or modified remotely. If uploaded to a software application, these data can be used to automate record keeping for regulatory compliance (e.g., environmental, validation, ISO9000, and safety standards).

Numerous device parameters are available from HART-compatible instruments that can be communicated to the control room and used for control, maintenance, and record keeping (Figure 4).

Figure 4: Examples of Device Parameters Sent to Control Room

Some HART devices perform complex calculations, such as PID control algorithms or compensated flow rate. Multivariable HART-capable instruments take measurements and perform calculations at the source, which eliminates time bias and results in more accurate calculations than are possible when performed in a centralized host.

Some HART field devices store historical information in the form of trend logs and summary data. These logs and statistical calculations (e.g., high and low values and averages) can be uploaded into a software application for further processing or record keeping.

The HART protocol provides access to all information in multivariable devices. In addition to the analog output

(primary variable), the HART protocol provides access to all measurement data that can be used for verification or

calculation of plant mass and energy balances.

Control RoomField Device


Improved Plant Operations


COST SAVINGS IN MAINTENANCE

The diagnostic capabilities of HART-communicating field devices can eliminate substantial costs by reducing downtime. The HART protocol communicates diagnostic information to the control room, which minimizes the time required to identify the source of any problem and take corrective action. Trips into the field or hazardous areas are eliminated or reduced.

When a replacement device is put into service, HART communication allows the correct operational parameters and settings to be quickly and accurately uploaded into the device from a central database. Efficient and rapid uploading reduces the time that the device is out of service. Some software applications provide a historical record of configuration and operational status for each instrument. This information can be used for predictive, preventive, and proactive maintenance.



Operational Flexibility The HART protocol allows two masters (primary and secondary) to communicate with slave devices and provide additional operational flexibility. A permanently connected host system can be used simultaneously, while a handheld terminal or PC controller is communicating with a field device (Figure 5).

Figure 5: Multimaster System

The HART protocol ensures interoperablility among devices through universal commands that enable hosts to easily access and communicate the most common parameters used in field devices. The HART DDL extends interoperability to include information that may be specific to a particular device. DDL enables a single handheld configurator or PC host application to configure and maintain HART-communicating devices from any manufacturer. The use of common tools for products of different vendors minimizes the amount of equipment and training needed to maintain a plant.

HART extends the capability of field devices beyond the single-variable limitations of 4–20 mA in hosts with HART capability.

TransmitterSecondary Master

Primary Master: Control System or Other Host Application

Analog

Digital Data(2–3 updates per second)

HART Interface

Power Supply



Instrumentation Investment ProtectionExisting plants and processes have considerable investments in wiring, analog controllers, junction boxes, barriers, marshalling panels, and analog or smart instrumentation. The people, procedures, and equipment already exist for the support and maintenance of the installed equipment. HART field instruments protect this investment by providing compatible products with enhanced digital capabilities. These enhanced capabilities can be used incrementally.

At the basic level, HART devices communicate with a handheld terminal for setup and maintenance. As needs grow, more sophisticated, on-line, PC-based systems can provide continuous monitoring of device status and configuration parameters. Advanced installations can also use control systems with HART I/O capability. The status information can be used directly by control schemes to trigger remedial actions and allow on-line reranging based on operating conditions and direct reading of multivariable instrument data.

COMPATIBILITY OF HART REVISIONS

As HART field devices are upgraded, new functions may be added. A basic premise of the HART Protocol is that new HART instruments must behave in precisely the same manner as older versions when interfaced with an earlier revision host system.

The HART communication protocol enables you to retain your previous investments in existing hardware and personnel.



Digital CommunicationA digital instrument that uses a microprocessor provides many benefits. These benefits are found in all smart devices regardless of the type of communication used. A digital device provides advantages such as improved accuracy and stability. The HART protocol enhances the capabilities of digital instruments by providing communication access and networking (Table 2).

Table 2: Digital Instruments Versus HART Instruments

Benefits HART Instruments Digital InstrumentsAccuracy and stabilityReliabilityMultivariableComputationsDiagnosticsMultiple sensor inputsEase of commissioningTag IDRemote configurationLoop checksAdjustable operational parametersAccess to historical dataMultidrop networkingAccess by multiple host devicesExtended communication distancesField-based controlInteroperability


GETTING THE MOST OUT OF HART SYSTEMS

Getting the Most out of HART SystemsTo take full advantage of the benefits offered by the HART communication protocol, it is important that you install and implement the system correctly. The following sections contain information that can help you to get the most from your HART system:

Wiring and InstallationIntrinsic safetyHART multidrop networksControl system interfacesMultiplexersReading HART data into nonHART systemsUniversal handheld communicatorPC configuration softwareCommissioning HART networksDevice status and diagnosticsConnecting a PC to a HART device or networkPC application development toolsControl in field devices



Wiring and InstallationIn general, the installation practice for HART communicating devices is the same as conventional 4-20mA instrumentation. Individually shielded twisted pair cable, either in single-pair or multi-pair varieties, is the recommended wiring practice. Unshielded cables may be used for short distances if ambient noise and cross-talk will not affect communication. The minimum conductor size is 0.51 mm diameter (#24 AWG) for cable runs less than 1,524 m (5,000 ft) and 0.81 mm diameter (#20 AWG) for longer distances.

CABLE LENGTH Most installations are well within the 3,000 meter (10,000 ft) theoretical limit for HART communication. However, the electrical characteristics of the cable (mostly capacitance) and the combination of connected devices can affect the maximum allowable cable length of a HART network. Table 3 shows the affect of cable capacitance and the number of network devices on cable length. The table is based on typical installations of HART devices in non-IS environments, i.e. no miscellaneous series impedance. Detailed information for determining the maximum cable length for any HART network configuration can be found in the HART Physical Layer Specifications.

Cable Capacitance – pf/ft (pf/m) Cable Length – feet (meters)

No. Network Devices

20 pf/ft(65 pf/m)

30 pf/ft(95 pf/m)

50 pf/ft(160 pf/m)

70 pf/ft(225 pf/m)

1 9,000 ft(2,769 m)

6,500 ft(2,000 m)

4,200 ft(1,292 m)

3,200 ft(985 m)

5 8,000 ft(2,462 m)

5,900 ft(1,815 m)

3,700 ft(1,138 m)

2,900 ft(892 m)

10 7,000 ft(2,154 m)

5,200 ft(1,600 m)

3,300 ft(1,015 m)

2,500 ft(769 m)

15 6,000 ft(1,846 m)

4,600 ft(1,415 m)

2,900 ft(892 m)

2,300 ft(708 m)

Table 3: Allowable cable lengths for 1.02 mm (#18 AWG) shield twisted pair



Intrinsic SafetyIntrinsic safety (IS) is a method of providing safe operation of electronic process-control instrumentation in hazardous areas. IS systems keep the available electrical energy in the system low enough that ignition of the hazardous atmosphere cannot occur. No single field device or wiring is intrinsically safe by itself (except for battery-operated, self-contained devices), but is intrinsically safe only when employed in a properly designed IS system.

INTRINSIC SAFETY DEVICES

HART-communicating devices work well in applications that require IS operation. IS devices (e.g., barriers) are often used with traditional two-wire 4–20 mA instruments to ensure an IS system in hazardous areas. With traditional analog instrumentation, energy to the field can be limited with or without a ground connection by installing one of the following IS devices:

Shunt-diode (zener) barriers that use a high-quality safety ground connection to bypass excess energy (Figure 6)Isolators, which do not require a ground connection, that repeat the analog measurement signal across an isolated interface in the safe-side load circuit (Figure 7 on page 19)

Both zener barriers and isolators can be used to ensure an IS system with HART-communicating devices, but some additional issues must be considered when engineering the HART loop.

Figure 6: 4–20 mA Loop with a Zener Barrier

Power Supply

250 Ω Load Resistor

Transmitter

Zener Barrier

HAZARDOUS SIDE SAFE SIDE

1–5 V Output Signal


Intrinsic Safety


Figure 7: 4–20 mA Loop with Isolator

DESIGNING AN IS SYSTEM USING SHUNT-DIODE BARRIERS

Designing an IS direct-current loop simply requires ensuring that a field device has sufficient voltage to operate, taking into account zener barrier resistance, the load resistor, and any cable resistance.

When designing an IS loop using shunt-diode barriers, two additional requirements must be considered:

The power supply must be reduced by an additional 0.7 V to allow headroom for the HART communication signal and yet not approach the zener barrier conduction voltage.The load resistor must be at least 230 Ω (typically 250 Ω).

Depending on the lift-off voltage of the transmitter (typically 10–12 V), these two requirements can be difficult to achieve. The loop must be designed to work up to 22 mA (not just 20 mA) to communicate with a field device that is reporting failure by an upscale, over-range current. The series resistance for the same zener barrier may be as high as 340 Ω. To calculate the available voltage needed to power a transmitter, use the following equation:

Power Supply Voltage – (Zener Barrier Resistance + Sense Resistance) × Operating Current (mA) = Available Voltage

Example: 26.0 V – (340 Ω + 250 Ω) × 22 mA = 13.0 V

Any cable resistance can be added as a series resistance and will reduce the voltage even further. In addition, the power supply to the zener barrier must also be set lower than the zener barrier conduction voltage. For example, a 28 V, 300 Ω zener barrier would typically be used with a 26 V power supply.

Power Supply

SAFE SIDEHAZARDOUS SIDE

4–20 mA Transmitter

250 Ω Load Resistor

Isolator

1–5 V Output Signal


Intrinsic Safety


While it is difficult to meet the two requirements noted above for a network using shunt-diode barriers, it can be done. Following are two possible solutions to the problem:1. Shunt the load resistor with a large inductor so that the load resistor

impedance is still high (and mainly resistive) at HART signal frequencies, but much lower at direct current. This solution, while it does work, is physically somewhat inconvenient.

2. Use an IS isolator rather than a shunt-diode barrier. The output voltage on the hazardous side is usually specified as greater than X Vdc at 20 mA (typically 14–17 V). This value already includes the voltage drop due to the internal safety resistor, so the only extra voltage drop is that due to cable resistance. System operation at 22 mA requires reducing the 20 mA voltage by 0.7 V (340 Ω × 2 mA).

DESIGNING AN IS SYSTEM USING ISOLATORS

The implementation of HART loops in an IS system with isolators requires more planning. An isolator is designed to recreate the 4–20 mA signal from the field device in the safe-side load circuit. Most older isolator designs will not carry the high frequencies of HART current signals across to the safe side, nor will they convey HART voltage signals from the safe side to the field. For this reason, HART communication through the isolator is not possible with these older designs. (It is still possible to work with a handheld communicator or PC with an IS modem on the hazardous side of the isolator.) When retrofitting HART instruments into an existing installation, inspect the system for isolators that may have to be replaced (any isolators that will not support HART signals).

IS device suppliers can assist with certification and performance specifications for their HART-compatible products. Field device manufacturers will also supply certification details for their specific products.

Major suppliers of IS isolators have introduced designs that are fully HART compatible. Modern IS isolators provide trouble-free design and operation and transparent communication in both directions.


Intrinsic Safety


MULTIDROP IS NETWORKS

HART multidrop networks are particularly suitable for intrinsically safe installations. With a multidrop configuration, fewer barriers or isolators are required. In addition, because each field device takes only 4 mA (for a total of 16 mA in a four-device loop), plain zener barriers can be used. With a 250 Ω load, 25 V – (340 + 250 Ω) × 16 mA = 15.5 V, which is well above the transmitter lift-off voltage and leaves a margin for cable resistance.

IS OUTPUT LOOPS For output devices such as valve positioners, direct-current voltage considerations will vary depending on the drive requirements of the device. Zener barriers may be possible. If not, modern HART-compatible output isolators are appropriate.

IS CERTIFICATION CONSIDERATIONS

If the HART loop contains an IS-approved handheld communicator or modem, slight changes may be needed to meet IS installation certification rules. Handheld communicators and modems add the HART signal voltage to the voltage level coming from the zener barrier or isolator. For example, a handheld communicator typically adds a maximum of 2 V to the loop. Therefore, when used with a 28 V zener barrier, a total of 30 V may theoretically be present in the loop. The allowable capacitance must be reduced by about 15% to account for this increase in voltage.

IS NETWORK CABLE LENGTH CALCULATIONS

The cable length calculation must include the resistance of both the zener barrier and the load resistor.



HART Multidrop NetworksThe HART communication protocol enables several instruments to be connected on the same pair of wires in a multidrop network configuration (Figure 8). The current through each field device is fixed at a minimum value (typically 4 mA) sufficient for device operation. The analog loop current does not change in relation to the process and thus does not reflect the primary variable. Communications in multidrop mode are entirely digital.

Figure 8: Multidrop Configuration

Standard HART commands are used to communicate with field instruments to determine process variables or device parameter information (see HART Commands on page 7). The typical cycle time needed to read information on a single variable from a HART device is approximately 500 milliseconds (ms). For a network of 15 devices, a total of approximately 7.5 seconds is needed to scan and read the primary variables from all devices. Reading information from multivariable instruments may take longer, as the data field will typically contain values for four variables rather than just one.

The typical multidrop network enables two-wire measurement devices to be connected in parallel. Two-wire loop-powered and four-wire active-source devices can be connected in the same network. If both two- and four-wire devices are used in the same network, three wires must be used to properly connect the devices (see Water Treatment Facility Upgrade on page 45).

Transmitters

Master Device

Modem

Auxiliary Power Supply


HART Multidrop Networks


MULTIDROP WITH HART FIELD CONTROLLERS

HART field controllers can also be wired in a multidrop network (Figure 9). Each analog output signal from the transmitter/controllers is isolated from every other output signal, which provides a cost-effective HART network configuration. In this case, the analog signals are not fixed and are used for the output signal to the controlled device.

Figure 9: HART Controllers with Multidrop

APPLICATION CONSIDERATIONS

Connecting HART field devices in a multidrop network can provide significant installation savings. The total cable length in a multidrop network is typically less than the maximum cable length in point-to-point connections because the capacitance of the additional devices reduces the distance that the HART signal can be carried (see Wiring and Installation on page 17).

CONFIGURING DEVICES FOR MULTIDROP OPERATION

Using the polling address structure of the HART protocol, up to 15 devices can be connected in a multidrop network. The analog current of a HART device can be fixed by setting its polling address to a number other than zero. With the HART protocol, each field instrument should be configured with different polling addresses or tag numbers before being connected to a multidrop network—otherwise, the master will not be able to establish communication with the slave devices.

Handheld Terminal Computer or

DCSPower Supply HART Interface

HART Transmitter

Control Valve

4–20 mA

+ –+ – + – + – + – + –

Power Supply Impedance

To save on installation costs, use HART multidrop networks for remote monitoring stations, tank farms, pipeline distribution systems, and other monitoring

applications in which fast update rates are not required.



Control System InterfacesWhen you change your existing control system by adding a HART interface, it is important to understand the complete functionality offered by the HART interface. While several control-system suppliers offer HART interfaces, not all interfaces provide the same functionality.

Control systems such as a DCS, PLC, or SCADA/RTU (remote terminal unit) implement only the functionality required for a given application. For example, a flow-control system may only read the primary variable of a device and provide no additional support for viewing or changing configuration information. Other control-system interfaces provide comprehensive HART support, maintaining complete configuration records for all connected devices.

Contact your system supplier for specific details on their HART interface(s). Use the form in Appendix A to obtain information from control-system suppliers to identify specific characteristics of their products.

HART I/O SUBSYSTEMS

Many HART-compatible I/O subsystems have multiple analog channels on each I/O card. Suppliers choose whether to provide one HART interface per channel or to share one HART interface among several channels. The number of shared channels per HART interface impacts the frequency of data updates from a HART field device and the HART functionality that is supported.

HART I/O FOR MULTIDROP SUPPORT

For the best performance and flexibility, one HART interface should be dedicated to each I/O channel. Systems that share only one HART interface among several I/O channels may not support multidrop networks. The effective update rate of a multiplexed interface is slow enough that the performance of multiplexed multidrop networks would not be practical. Some suppliers enable multidrop support by fixing the HART interface to one specific I/O channel. However, the other channels on that card may then not be available for HART communications.

HART I/O FOR BURST MODE SUPPORT

Burst mode is an optional implementation in a field device. Receiving burst mode messages is optional in a host as well. To take full advantage of burst mode, the I/O system should have one HART interface for each channel. If the HART interface is shared by more than one channel, messages sent by the field device may not be detected by the control system. If the system does not have the ability to configure burst mode in the field device, a handheld terminal or other configuration tool is required.


Control System Interfaces


DATA HANDLING All HART-compatible control systems can read the digital primary variable from a slave device. However, some system architectures may not be able to accommodate textual data (e.g., tag and descriptor fields). In these cases, the controller is able to read the process variable, but may not have direct access to all other data in the HART device.

PASSTHROUGH FEATURE

Some control systems are integrated with a configuration or instrument- management application. In these systems, the control system passes a HART command, issued by the management application, to the field device via its I/O interface. When the control system receives the reply from the field device, it sends the reply to the management application. This function is referred to as a passthrough feature of the control system.

GATEWAYS Gateways can be used to bring HART digital data into control systems that do not support HART-capable I/O. Some systems support HART gateways with communication protocols such as Modbus, PROFIBUS DP, or TCP/IP Ethernet. The typical HART gateway supports all universal commands and a subset of the common practice commands. Support varies depending on the gateway supplier. Some gateways support access to device-specific information.

SCADA/RTU SYSTEMS

RTUs used in SCADA systems use a special telemetry to communicate with the control system. RTUs have the same considerations regarding multidrop and burst mode support as other systems. However, implementation is made more complex because RTUs often communicate to an upper-level host using a communication protocol other than HART (e.g., Modbus). While there are many benefits to implementing HART in an RTU (support of multidrop, burst mode, and multivariable instruments), HART data are only available to the central host system if the telemetry protocol supports the transfer of HART commands or specific HART data (see Multidrop for Tank Farm Monitoring on page 40).



MultiplexersHART-compatible multiplexers are ideal for users who want to interface with a large number of HART devices. Multiplexers can be modular and are capable of supporting both point-to-point and all-digital (multidrop) HART communication modes. Communication between a multiplexer and a host application depends on the multiplexer capabilities (e.g., RS232C, RS485, Modbus, and TCP/IP Ethernet).

When installing HART multiplexer systems, the following capabilities should be considered:

Number of HART channels supportedNumber of HART channels that share a HART modemBurst mode supportMultidrop supportMethod of communication with the host computer or control system

MULTIPLEXER AS THE PRIMARY I/O SYSTEM

HART multiplexers can be used as the primary I/O front end for a HART-based control or monitoring system (Figure 10). Typically, a PC acts as the host, providing the human-machine interface and performing other high-level functions. The multiplexer continuously monitors the field devices, reports the current readings and instrument status to the host, and passes HART commands from the host computer to the field devices.

Figure 10: HART Multiplexer as the Primary I/O System

PARALLEL MONITORING WITH A MULTIPLEXER

When a traditional 4–20 mA control system is using the analog signals for measurement and control outputs, a HART multiplexer can be added to the network to gain access to the digital HART signal. Using a multiplexer enables a supervisory computer to monitor diagnostics and device status, access configuration information, and read any additional process inputs or calculations not provided by the 4–20 mA signal.

Multiplexer

Field Devices

Field Device

SCADA


Multiplexers


Two types of multiplexers are used in conjunction with a control system. A multiplexer wired in parallel with the field wiring is commonly used when the control system wiring is already in place (Figure 11).

Figure 11: HART Multiplexer with Existing I/O

A multiplexer can also be an integral part of the control system as a third-party I/O (Figure 12). As an I/O system, the multiplexer can include IS barriers and other filtering capabilities and provide services to the field device, such as galvanic isolation or power. For this type of installation, no additional terminations or space are required. The multiplexer can also act as a gateway to convert the HART messages to another protocol such as Modbus, PROFIBUS, or Ethernet..

Figure 12: HART Multiplexer Integrated with I/O

Use a HART multiplexer to gain access to the digital HART signal.

Automation and Display System Supervisory

ComputerControllers

I/O

Transmitter

Control Valves

Multiplexer

Controller

I/O

Supervisory Computer

Automation and Display System

Transmitter Control Valve



Reading HART Data into NonHART SystemsMany HART products are able to perform more than one measurement or output function (e.g., make multiple process measurements, calculate process information, and provide positioner feedback information). All of this information can be easily accessed digitally. However, existing controllers or interface equipment may not have the ability to read digital HART data. Products are available that can read HART digital signals and convert them to analog or contact information, which enables any traditional analog/digital I/O to take full advantage of the benefits of HART-communicating devices. The Rosemount Inc. Tri-Loop module and the Moore Industries Site Programmable Alarm (SPA) are two such products.

HART DATA-CONVERSION PRODUCTS

The Tri-Loop module monitors a HART loop for a bursting message and converts three of the four possible variables in HART command number three to analog outputs (Figure 13). The conversion enables the field device to provide a total of four analog signals over a single pair of wires run from the field..

Figure 13: Tri-Loop Module

Channel 1Channel 2

Channel 3

Control SystemRail-Mounted Tri-Loop Module

Field Terminals

4–20 mA Signals for Secondary Variables


Reading HART Data into NonHART Systems


The SPA module continuously communicates with any HART-capable device and provides contact closure outputs (alarm trips) based on the information received (Figure 14). For example, the SPA can be configured to monitor the device-status information inherent in the HART communication protocol and trigger events such as local on/off applications or alarms. The SPA can also initiate emergency shutdown action if problems are detected with a field device in critical loop applications.

Figure 14: SPA Module

Both HART Tri-Loop and SPA provide multivariable product support on a loop-by-loop basis.

4–20 mA and HART Digital

SignalsHART

TransmitterHART Communicator

Process and

Diagnostic Data

HART Master

Annunciator

Event Recorder

Control System

Shutdown Controls



Universal Handheld CommunicatorThe 275 Universal HART Communicator is available from major instrumentation suppliers around the globe and is supported by all member companies in the HCF. Using HART DDL, the communicator can fully communicate with and configure any HART device for which it has a DD installed. If the communicator does not have the DD for a particular network device installed, it can still communicate with that device using the universal and common practice commands (see HART Commands on page 7). The HCF provides centralized control and registration for all DDs that can be loaded into the communicator. An index of registered DDs can be found on the world wide web at <http://www.hartcomm.org>.

Figure 15: 275 Universal Handheld Communicator

Use the 275 Universal HART Communicator to communicate with and configure any

HART-communicating device.



PC Configuration SoftwareMany instrument manufacturers, as well as some independent software developers, offer HART communication software for PCs with capabilities similar to and beyond those offered by a HART handheld communicator.

The software packages listed in Table 4 are used for configuration management, parameter tuning, and data acquisition with a HART device. The list is not comprehensive, and all software applications are not functionally equivalent. A number of product-specific software applications are also available for diagnostics. An RS232 HART interface or other interface device connects the PC running the HART application software to the field devices.

SUMMARY TABLE OF HART SOFTWARE

Table 4: HART Software

Use special software applications to continuously monitor the status of connected field devices and log status changes as they occur, which may help reduce

the costs of regulatory compliance.

Software Application Manufacturer

Asset Management Solutions (AMS)

Configuration and calibration management Fisher-Rosemount

CONF301 HART Configurator Configuration management Smar International

CONFIG Configuration management Krohne

Cornerstone Base Station

Configuration and calibration management

Applied System Technologies

Cornerstone Configurator Instrument configuration Applied System

Technologies

H-View Configuration management and data acquisition Arcom Control Systems

IBIS Configuration management EB Hartmann & Braun

IBIS Configuration management Samson

K-S Series Configuration management ABB

Mobrey H-View Configuration management KDG Mobrey

Pacemaker Configuration management UTSI International Corporation

SIMATIC PDM Configuration management Siemens

Smart Vision Configuration management EB Hartmann & Braun/Bailey Fischer & Porter

XTC Configuration Software Configuration management Moore Products Co.



Commissioning HART NetworksHART-based instruments have several features that significantly reduce the time required to fully commission a HART network (loop). When less time is required for commissioning, substantial cost savings are achieved.

DEVICE VERIFICATION

Before installation, manufacturers usually enter device tags and other identification and configuration data into each field instrument. After installation, the instrument identification (tag and descriptor) can be verified in the control room using a configurator (handheld terminal or PC). Some field devices provide information on their physical configuration (e.g., wetted materials)—these and other configuration data can also be verified in the control room. The verification process can be important in conforming to governmental regulations and ISO quality requirements.

The commissioning process can be further streamlined by connecting a PC configurator to each HART loop online, either by integration with the control system or by using one of the many available HART multiplexing I/O systems (see Multiplexers on page 26). With this centralized approach, there is no need to move the configuration device from one termination point to the next while commissioning all devices on the network.

LOOP INTEGRITY CHECK

Once a field instrument has been identified and its configuration data confirmed, the analog loop integrity can be checked using the loop test feature, which is supported by many HART devices. The loop test feature enables the analog signal from a HART transmitter to be fixed at a specific value to verify loop integrity and ensure proper connection to support devices such as indicators, recorders, and DCS displays.

AS-INSTALLED RECORD KEEPING

A HART configurator also facilitates record keeping. As-installed device configuration data can be stored in memory or on a disk for later archiving or printing.

Use the HART protocol loop test feature to check analog loop integrity and ensure a proper physical

connection among all network devices.


APPENDICESAPPENDICESAPPENDICESGETTING THE MOST OUT OF HART SYSTEMS

Device Status and DiagnosticsMost HART field instruments provide both status information and diagnostic information. The HART protocol defines basic status information as information that is included with every message from a field device. Basic status information enables the host application to immediately identify warning or error conditions detected by the field device. Status messages also enable the user to differentiate between measurements that are outside sensor or range limits and actual hardware malfunctions. Examples of status messages are:

Field device malfunctionConfiguration changedCold startMore status availableAnalog output current fixedAnalog output saturatedNonprimary variable out of limitsPrimary variable out of limits

HART instruments can implement extensive, device-specific diagnostics. The amount and type of diagnostic information is determined by the manufacturer and varies with product and application. Diagnostic information can be accessed using the HART communication protocol. Host applications using DD files can interpret and display diagnostic information. Applications not using DD technology may require product- specific software modules to interpret diagnostic information.

Many manufacturers offer special software applications for their own products. Some modules allow you to customize for specific products. Manufacturers of valve actuators have made extensive use of this capability to provide preventative and predictive diagnostic information that greatly enhances the value of their products as compared to conventional actuators.

Several software applications are available that provide continuous communication with field devices using a HART-compatible multiplexer and HART I/O (see Multiplexers on page 26). These applications provide real-time monitoring of status and diagnostic information.



Connecting a PC to a HART Device or NetworkPCs are commonly used for HART host applications for configuration and data acquisition. A specially designed device (Table 5) allows the HART network to be connected to the RS232C serial port or PCMCIA slot of a PC (Figure 16).

Table 5: HART Interfaces

Figure 16: RS232 HART Interface

Product Name Manufacturer

Commubox Endress + Hauser

FSK-Modem EB Hartmann & Braun

HT311 RS232 Interface Smar International

VIATOR PCMCIA HART Interface MACTek

VIATOR RS232 HART Interface MACTek

Field Device

RS232 HART Interface Handheld Terminal

PC/Host Application

Power Supply



PC Application Development ToolsSoftware drivers are available to assist in the development and integration of PC applications with HART networks. Table 6 shows a partial list of products available.

Table 6: PC Development Tools

Product Name Description Manufacturer

Hview Provides DDE server Arcom Control Systems

HRT VBX 16-bit Visual Basic driver Borst Automation

HRT OCX 32-bit ActiveX Control Borst Automation

HART OPC Server OPC Server HCF (via member

companies)

HL-LinkPro HART driver for LabVIEW Cardiac Systems Solutions



Control in Field DevicesMicroprocessor-based smart instrumentation enables control algorithms to be calculated in the field devices, close to the process (Figure 17). Some HART transmitters and actuators support control functionality in the device, which eliminates the need for a separate controller and reduces hardware, installation, and start-up costs. Accurate, closed-loop control becomes possible in areas where it was not economically feasible before. While the control algorithm uses the analog signal, HART communication provides the means to monitor the loop and change control setpoint and parameters.

Figure 17: Transmitter with PID (HART Slave)

Placing control in the field enhances control functionality. Measurement accuracy is maintained because there is no need to transmit data to a separate controller. Control processing takes place at the high update rate of the sensor and provides enhanced dynamic performance.

PC-Based Operator Interface

Muiltiplexer (HART Master)

4–20 mA to Position Valve

Control ValveHART Transmitter with PID Slave

Modbus Link (RS232)


Control in Field Devices


HART FIELD CONTROLLER IMPLEMENTATION

A HART field controller takes advantage of the HART protocol’s simultaneous analog and digital signaling by converting the transmitter’s traditional analog measurement output into a control output. The analog signal from the smart transmitter (controller) is used to manipulate the field device (Figure 18). The analog output signal also carries the HART digital signal, which is used for monitoring the process measurement, making setpoint changes, and tuning the controller.

Figure 18: Smart Transmitter with PID

The communication rate of the HART protocol (2–3 updates per second) is generally perceived as too slow to support closed-loop control in the central host. With control in the field, the control function no longer depends on the HART protocol’s communication rate. Instead, the control signal is an analog output that is updated at a rate that is much faster than can typically be processed in a conventional control system. Processing rates vary from 2–20 updates per second, depending on the product. The HART digital communication rate remains sufficient for monitoring the control variable and changing setpoint values.

+Power Supply

Smart Transmitter

Control Valve

Bypass Capacitor

Resistor


INDUSTRY APPLICATIONS

Industry ApplicationsMany companies in a wide variety of industries have already realized the advantages of using the HART communication protocol. This section describes some applications in detail and outlines the tangible benefits that result. The applications have been grouped into the following sections:

Inventory-management applicationsCost-saving applicationsRemote-operation applicationsOpen-architecture applications



Inventory-Management ApplicationsAccurate measurements for inventory management are essential in all industries. The HART communication protocol enables companies to make sure inventory management is as efficient, accurate, and low cost as possible.

HART MULTIDROP NETWORK FOR TANK LEVEL AND INVENTORY MANAGEMENT

Tank level and inventory management is an ideal application for a HART multidrop network (Figure 19). The HART network digital update rate of two PVs per second is sufficient for many tank-level applications. A multidrop network provides significant installation savings by reducing the amount of wiring from the field to the control room as well as the number of I/O channels required. In addition, many inexpensive process-monitoring applications are commercially available to further cut costs.

Figure 19: Inventory Management with Multidrop

One company uses a HART multiplexer to digitally scan field devices for level-measurement and status information. The information is forwarded to the host application using the Modbus communication standard. Multivariable instruments further reduce costs by providing multiple process measurements, such as level and temperature, which reduces the wiring and number of process penetrations required.

HART Field Multiplexer

Transmitters

Storage Tanks


Inventory-Management Applications


MULTIDROP FOR TANK FARM MONITORING

In one tank farm application, 84 settlement tanks and filter beds on a very large site (over 300,000 m2) are monitored using HART multidrop networks and HART RTUs (see SCADA/RTU Systems on page 25). The HART architecture required just eight cable runs for 84 tanks, with 10–11 devices per run (Figure 20). Over 70 individual runs of over 500 m each were eliminated. Cable savings were estimated at over $40,000 when compared to a conventional installation. RTU I/O was also reduced, which resulted in additional hardware and installation savings. The total installed cost was approximately 50% of a traditional 4–20 mA installation.

Figure 20: Tank Farm Monitoring with Multidrop

HART Multiplexer

Storage Tanks

Control Room

Storage Tanks


Inventory-Management Applications


UNDERGROUND PETROLEUM STORAGE WITH HART COMMUNICATION FOR ACCURACY

Underground salt caverns are frequently used for crude oil storage. One customer pumps oil from barges into the storage caverns. An ultrasonic flowmeter records the total flow. To get the oil out of the caverns, a brine solution is pumped into the cavern through a magnetic flowmeter. Brine and crude oil flowing in both directions are measured and reported to the DCS using the HART communication protocol for accuracy. The DCS tracks flow rate and total quantity to maintain a certain pressure inside the caverns (Figure 21).

Figure 21: Underground Petroleum Storage

HART Transmitter Interface

Field InstrumentsOil Caverns

HART Transmitter Interface

Note: Digital accuracy for flow accuracy and flow totals



Cost-Saving Applications

WASTEWATER TREATMENT PLANT UPGRADE

A Texas wastewater treatment plant replaced stand-alone flowmeters and chart recorder outstations that required daily visits for totalization with a HART system. HART-based magnetic flowmeters were multidropped into HART RTUs to create a cost-effective SCADA network. The use of HART technology reduced system and cable costs, enhanced measurement accuracy, and eliminated time-consuming analog calibration procedures.

A system of 11 HART multidrop networks was used to connect 45 magnetic flowmeters from different plant areas. Each flowmeter communicated flow rate and a totalized value over the HART network. Multidrop networks eliminated the need for additional hardware and PLC programming while providing a more accurate totalized value. Complex and costly system integration issues were also avoided—for example, there was no need for synchronization of totals between the host and field PLCs.

Multidrop networking further reduced the installation cost by reducing the required number of input cards from the traditional 45 (for point-to-point installations) to 11. Maintenance was simplified because of access to instrument diagnostic and status data.

Use HART multidrop networking to reduce installation and maintenance costs.




APPLIANCE MANUFACTURING WITH MULTIDROP

A consumer appliance manufacturer used the networking capability of the HART protocol to measure level, flow, and pressure. HART multidrop provided substantial wiring and installation savings as well as digital accuracy with the elimination of the analog to digital (A/D) and digital to analog (D/A) conversions of the instrument and PLC I/O. Figure 22 shows pressure transmitters connected to a PLC via smart transmitter interface multiplexers.

Figure 22: Multidrop Network Example

Storage Tanks

Communication Module

Smart Transmitter Interface

Highway

Terminal Block Module

PLC




REMOTE REZEROING IN A BREWERY

The benefits of remote monitoring and rezeroing of smart transmitters using the HART protocol are dramatically illustrated in this example of two smart transmitters that control the fluid level in lauter tubs in a brewhouse application. Similar benefits would be realized in any application involving a closed vessel.

Two smart transmitters are installed on each lauter tub—one on the bottom of the tank and the other about nine inches from the bottom. The bottom transmitter is ranged ±40 inH2O; the upper transmitter is ranged 0–30 inH2O. As the lauter tub is filled, the bottom transmitter senses level based on pressure. When the level reaches the upper transmitter, that point is marked as the new zero-level point, and the upper transmitter becomes the primary sensing instrument for the lauter-tub level. The nine-inch zero-level offset from the bottom of the tank is necessary to accommodate loose grain that settles in the bottom of the tank.

Transmitters that are coordinated and working together control fluid level in each lauter tub to within a few barrels. However, the upper transmitter requires periodic maintenance or replacement and rezeroing. An undetected false upper-transmitter level reading can cause a tank level error of up to 40 gallons.

The usual procedure for transmitter rezeroing takes about 95 minutes and has been required as frequently as twice a day. Rezeroing a transmitter using configuration software and PLC interface modules eliminates the need to locate and identify the problem at the site as well as the need for verification by control-room personnel and greatly reduces the chance for inadvertent errors. Estimated total time to rezero each transmitter is reduced to 15 minutes.

Through the configuration software’s instrument-status and diagnostic capabilities, a false level indication can be automatically detected while a lauter tub fill is in progress. The affected transmitter can then be automatically rezeroed by programming logic in the programmable controller to issue the appropriate command to the instrument.




WATER TREATMENT FACILITY UPGRADE

HART transmitters and a control system with HART capability were chosen to upgrade a water treatment facility. The completed installation reduced capital, engineering, and installation costs. The process dynamics of the water treatment facility allowed the HART instruments to be used in all-digital mode without compromising plant performance.

The water treatment plant is divided into two areas, each with 14 filters. Each area is controlled by a separate control system for complete autonomy. A HART network monitors each filter for filter level, filter bed differential, and filter outlet flow. The multidrop installation used a three-wire system in order to accommodate both the two-wire and the four-wire devices (magnetic flowmeters) in use (Figure 23) (see Multidrop on page 6).

Figure 23: Multidrop Networks with 2-Wire and 4-Wire Devices

Because the water treatment facility had a modular design, the use of HART instruments allowed the configuration from the one filter network to be copied to the others, which reduced the implementation time. Engineering, system configuration, drafting, commissioning, maintenance, and documentation were simplified. A reduced I/O card count also saved money.

Main Power

4 mA

12 mA

4 mA

Pressure Transmitters

Magnetic Flowmeter




IMPROVED DIAGNOSTICS

A cleaning materials supplier required periodic checkup of the instrument condition and configuration information as compared to the initial installation. The field transmitters provided a historical record of status changes along with current configuration information. Periodic download of this information was made possible using PLC ladder logic developed for HART instruments.



Remote-Operation ApplicationsUNMANNED OFFSHORE GAS PRODUCTION WITH HART NETWORKS

Choosing the HART communication protocol for all-digital communication in a wide-area network enabled one company to have real-time monitoring and control, access to diagnostics, and maintenance capabilities—all from a remote location.

Over half of the 500 transmitters on 15 platforms could be multidropped with update rates of three seconds (six devices), which resulted in substantial savings in wiring, I/O, and installation. The remaining devices (flowmeters) required a faster response and were wired point to point using digital HART communications to transmit the process data. The flowmeters used the optional burst mode, which provided an update rate of 3.7 times per second. All-digital communications provided maximum accuracy and eliminated potential errors from input scaling, conversion, and drift (see Multidrop on page 6).

Figure 24: RTU Application

Each platform’s RTU provided a link to approximately 50 temperature, pressure, and flow transmitters (Figure 24). The RTU used the multimaster capability of the HART protocol to enable the second RTU to act as a hot standby, which monitored activity and was able to take over if a failure occurred. The RTUs provided links with the emergency and safety systems and a local interface for maintenance personnel. The Modbus protocol was used for communication to the central SCADA system.

Standby RTUPrimary RTU

Modbus Link

HART Multiplexers

Transmitters

Transmitters

Radio Antennae


Remote-Operation Applications


VENEZUELA GAS-LIFT PROJECT

In a Venezuela gas-lift project, HART multidrop technology was used for remote operation of offshore gas-lift production wells at considerable savings (Figure 25):

30% decrease in installation costs16:1 reduction of input modulesReduced cost of I/O cards in the RTURemote rerangingRemote access to the transmitter status for improved process uptime

Figure 25: Offshore Gas-Lift Project

Microwave TowersRadio Antennae

Electric Valve

Configuration and

Maintenance Tools

HART Transmitters

Control Room



Open-Architecture ApplicationsOIL REFINERY EXPANSION

The best way to judge the openness of a communication protocol is by the number of products supported. By this standard, the HART protocol is perhaps the most open of any field-communication protocol available today.

In a major refinery expansion, an oil company weighed the advantages of using either a proprietary system or a HART-based system. The results indicated that the company could use HART digital instruments in 92% of their applications, compared to only 33% with the proprietary system. Choosing HART products resulted in an incremental $23,000 in savings due to commissioning efficiencies and ongoing maintenance and diagnostic capabilities.

The oil company used a traditional control system with analog I/O and supplemented the control capability with an online maintenance and monitoring system. All of the HART field devices were monitored from a central location (Figure 26).

Figure 26: Online Implementation

Fisher Fisher

Ethernet LinkControl Display System

Maintenance Station

Controller

I/O I/OHART Multiplexer

HART Transmitter Control Valve


Open-Architecture Applications


HART WITHIN A PROFIBUS NETWORK

HART field devices can be seamlessly integrated with PROFIBUS DP networks using the HART/DP Link, which enables the connection of four HART devices and facilitates the passthrough of HART commands to host applications on the DP network (Figure 27). The HART/DP Link supports IS installations.

Figure 27: HART Within a PROFIBUS Network

PCs with HART Applications

PLC

DP/PA Link

HART Instruments

Remote I/O

HART/DP Link

Profibus PA

DP/ASI Link

PROFIBUS DP


Open-Architecture Applications


HART/DDE SERVER

Cost-effective level- and temperature-monitoring systems can be designed using HART multidrop networks and commercially available HART/DDE interface software. HART/DDE interface software allows any compliant application (e.g., spreadsheet) to directly read the process data and status information available in HART field devices. A HART interface module connected to the PC’s serial port is needed for this HART monitoring application (Figure 28).

Figure 28: Multidrop Network

Transmitter

Spreadsheet Data Logging

RS232 HART Interface

Power Supply


WHERE TO GET MORE INFORMATION

Where To Get More InformationWHAT INFORMATION IS AVAILABLE?

To serve the growing interest in HART-related products, the HCF publishes a library of additional documents, articles, and overviews. The following information is currently available:

HART specificationsTechnical overviewApplication notesTechnical assistanceTraining classes

WHERE TO FIND INFORMATION

By Mail

HART Communication Foundation 9390 Research Blvd, Suite I-350 Austin, TX 78759 USA

By Phone

Call 512-794-0369.

By Fax

Send correspondence to 512-794-3904.

By E-mail

Send correspondence to <[email protected]>.

Online

Visit the HCF website at <http://www.hartcomm.org>.



Glossary275 HART Communicator

A handheld master device that uses the HART communication protocol and DDL to configure or communicate with any HART smart device

Bell 202 A U.S. telephone standard that uses 1,200 Hz and 2,200 Hz as 1 and 0, respectively, at 1,200 baud; a full duplex communication standard using a different pair of frequencies for its reverse channel; HART uses Bell 202 signals but is a half-duplex system, so the reverse channel frequencies are not used

Burst (Broadcast) Mode A HART communication mode in which a master device instructs a slave device to continuously broadcast a standard HART reply message (e.g., value of a process variable) until the master instructs it to stop bursting

Cable Capacitance Per Unit of Length

The capacitance from one conductor to all other conductors (including the shield if present) in the network; measured in feet or meters

Cable Resistance Per Unit of Length

The resistance for a single wire; meausred in feet or meters

Closed-Loop Control A system in which no operator intervention is necessary for process control

Communication Rate The rate at which data are sent from a slave device to a master device; usually expressed in data updates per second

DCS See Distributed Control System.

DD See Device Description.

DDL See Device Description Language.

Device Description A program file written in the HART Device Description Language (DDL) that contains an electronic description of all of a device’s parameters and functions needed by a host application to communicate with the device

Device Description Language

A standardized programming language used to write DDs for HART-compatible field devices

Distributed Control System

Instrumentation (input/output devices, control devices, and operator interface devices) that permits transmission of control, measurement, and operating information to and from user-specified locations, connected by a communication link

GLOSSARY

© 2003HART Communication Foundation Page 71

GlossaryField The area of a process plant outside the control room where measurements

are made, and to and from which communication is provided; a part of a message devoted to a particular function (e.g., the address field or the command field)

Field Device A device generally not found in the control room; field devices may generate or receive an analog signal in addition to the HART digital communication signal

Frequency Shift Keying Method of modulating digital information for transmission over paths with poor propagation characteristics; can be transmitted successfully over telephone systems

FSK See Frequency Shift Keying.

Gateway A network device that enables other devices on the network to communicate with a second network using a different protocol

HART Command Set A series of commands that provide uniform and consistent communication for all master and slave devices; includes universal, common practice, and device-specific commands

HART Communication Protocol

Highway Addressable Remote Transducer communication protocol; the industry standard protocol for digitally enhanced 4–20 mA communication with smart field devices

HART Loop A communication network in which the master and slave devices are HART smart or HART compatible

Host Application A software program used by the control center to translate information received from field devices into a format that can be used by the operator

Interoperability The ability to operate multiple devices, independent of manufacturer in the same system, without loss of functionality

Intrinsic Safety A certification method for use of electrical equipment in hazardous (e.g., flammable) environments; a type of protection in which a portion of an electrical system contains only intrinsically safe equipment that is incapable of causing ignition in the surrounding environment

Intrinsic Safety Barrier A network or device designed to limit the amount of energy available to the protected circuit in a hazardous location

IS See Intrinsic Safety.

GLOSSARY

Glossary


Master Device A device in a master-slave system that initiates all transactions and commands (e.g., central controller)

Master-Slave Protocol Communication system in which all transactions are initiated by a master device and are received and responded to by a slave device

Miscellaneous Series Impedance

The summation of the maximum impedance (500 Hz–10 kHz) of all devices connected in series between two communicating devices; a typical nonintrinsically safe loop will have no miscellaneous series impedance

Modem Modulator/demodulator used to convert HART signals to RS232 signals

Multidrop Network HART communication system that allows more than two devices to be connected together on a single cable; usually refers to a network with more than one slave device

Multimaster Multimaster refers to a communication system that has more than one master device. The HART protocol is a simple multimaster system allowing two masters; after receiving a message from a slave device, the master waits for a short time before beginning another transmission, which gives the second master time to initiate a message

Multiplexer A device that connects to several HART loops and allows communication to and from a host application

Multivariable Instrument A field device that can measure or calculate more than one process parameter (e.g., flow and temperature)

Network A series of field and control devices connected together through a communication medium

Parallel Device Capacitance

The summation of the capacitance values of all connected devices in a network

Parallel Device Resistance

The parallel combination of the resistance values of all connected devices in the network; typically, there is only one low-impedance device in the network, which dominates the parallel device-resistance value

Passthrough A feature of some systems that allows HART protocol send-and-receive messages to be communicated through the system interface

PID Proportional-integral-derivative

PID Control Proportional-plus-integral-plus-derivative control; used in processes where the controlled variable is affected by long lag times

GLOSSARY


GlossaryPoint to Point A HART protocol communication mode that uses the conventional

4–20 mA signal for analog transmission, while measurement, adjustment, and equipment data are transferred digitally; only two communicating devices are connected together

Polling A method of sequentially observing each field device on a network to determine if the device is ready to send data

Polling Address Every HART device has a polling address; address 0 is used for point-to-point networks; addresses 1–15 are used in multidrop networks

Process Variable A process parameter that is being measured or controlled (e.g., level, flow, temperature, mass, density, etc.)

Protocol A set of rules to be used in generating or receiving a message

PV See Process Variable.

Remote Terminal Unit A self-contained control unit that is part of a SCADA system

RTU See Remote Terminal Unit.

SCADA See Supervisory Control and Data Acquisition.

Slave Device A device (e.g., transmitter or valve) in a master-slave system that receives commands from a master device; a slave device cannot initiate a transaction

Smart Instrumentation Microprocessor-based instrumentation that can be programmed, has memory, is capable of performing calculations and self-diagnostics and reporting faults, and can be communicated with from a remote location

Supervisory Control and Data Acquisition

A control system using communications such as phone lines, microwaves, radios, or satellites to link RTUs with a central control system

Zener Type of shunt-diode barrier that uses a high-quality safety ground connection to bypass excess energy

GLOSSARY

S- Advertising supplement to CONTROL

When end-users deploy devices enabled by the HART Communication Proto-col, they quickly discover the technol-

ogy’s reliability, ease of use, flexibility, robustness, and cost-effectiveness. They also learn how HART has proven itself in the field, whether it’s in pro-cess control or power plant applications.

Kevin Kerls, of biotechnology manufacturer Genentech Inc. in South San Francisco, and Jerry Lowery, of the Ohio State University in Colum-bus, also attest to the essential value of HART in industrial automation applications.

“You can use HART to implement all the high-value functions of other bus technologies—Foun-dation fieldbus, Profibus and DeviceNet—but at a fraction of their cost by using infrastructure that you probably already have in your plant today,” explains Kerls, a senior automation engineer in Genentech’s automation group. Kerls is helping automate Genentech’s CCP2 facility in Vacaville, Calif. which is currently under construction and is expected to produce 200,000 liters of oncology pharmaceuticals by 2009.

“In a regulated industry, it’s critical to manage de-vice configurations,” says Kerls. “Integrating HART Communication with our distributed control system (DCS) allows us to mitigate both of these risks.”

Meanwhile, on Ohio State’s main campus, Lowery also extols the virtues of HART. Most technicians are familiar with HART-enabled com-municators. “The technicians love them. They’re superior for the technicians,” says Lowery, a con-trol systems engineer at OSU’s McCracken Power Plant. Another important feature is that HART is an open standard. “It gives everyone a common thing to

work toward,” he explains. “HART is the way to go. It makes life so much easier.”

Ivy Towers, HoT and Cold HarTOperating continuously, the McCracken plant provides 85% of the Buckeyes’ steam-based energy needs. The steam is used for heating, humidifica-

tale of two plants

Two HART Projects Keep Plants Competitive

A tale of two different projects in two different industries that achieve similarly impressive results

photo courtesy of the Ohio State University

tion, sterilization, chilled-water, compressed air and domestic hot-water production. The plant has five industrial boilers. Presently, the oldest is a Babcock & Wilcox (B&W) D-Style, 600-psi, 220,000 lbs/hr unit. Two new 200-psi Nebraska D-style units that produce 220,000 lb/hr of steam were installed in 2004-05. Two more Nebraska Ds are now being installed, and the 200-psi, 150,000-lb/hr units are ex-pected to be online by January 2007. Co-located at the plant are seven York chillers, and three Caterpil-lar emergency diesel generators.

Lowery doesn’t mince words about how impor-tant HART is to the plant. “We have approximate-ly 200 to 250 HART-enabled devices. Without HART, this plant wouldn’t operate,” he says.

HART also helps the plant’s technicians save time finding instrument problems. “We don’t have to spend as much time looking for what’s wrong,” adds Lowery.

For example, staffers recently observed inter-mittent signal failures on a temperature trans-mitter on one boiler’s superheater (SH) vent control, which caused the vent to go into the wrong position. How-ever, thanks to a HART-enabled Honeywell DCS system on the B&W boiler, they were able to quickly correct the problem.

“This was the first time we’d seen this type of HART information,” he explains. The spreadsheet showed data with a log/time-stamp describing an event. In this case, descriptions included “primary variable (PV) was out of sensor limits” or “bad: check measuring” and “field device malfunction.”

Once the staff found the event descriptions in the event log, they solved their problem the same day. “We knew exactly what was wrong. The technician went out, and repaired the resistance temperature device (RTD),” he says. “With the HART-enabled DCS, our technicians know what the problem is.”

resulTs Proven, rIsks lessened A second event at Ohio State involved an SH vent-control valve failure. The McCracken plant’s valve wouldn’t open or would become stuck while par-tially open, Lowery recalls. “A vent-control valve failure put the boiler superheater at risk.”

Lowery decided to use the HART protocol’s digi-tal PV (DigPV) that was accessible from the DCS.

He used the valve positioner digital PV to validate the valve’s position. If the valve didn’t reach proper position in 30 seconds, an alarm would sound and a warning would be displayed on the HMI screen.

The DigPV, which proved that the valve was not seating properly, and the digital secondary vari-able (DigSV), in this case positioner temperature, indicated that a temperature “exceedance” had oc-curred. “The HART secondary value or device tem-perature on the original positioner was trended and proved that the device never exceeded its maximum operating temperature of 50 ºC,” adds Lowery.

These data convinced the vendor to replace the valve positioner, “and the problem went away,” Lowery notes. This is important because the vendor originally claimed the boiler’s opera-tion had overheated and caused the SH vent-control valve to become stuck.

Ohio State also convinced the vendor to fix six SH vent valves saving approximately $10,000. Also, the combined digital PVs and SVs’ perfor-

mance not only saved a potential $300,000 cost of replacing the existing superheater, but also led the vendor to install a more reliable positioner.

Lowery appreciates this digital value functionality. “Digital PVs are extremely valuable in critical loops to validate the analog position with the digital position,” he adds.

Besides diagnostics, having analog and digital communication available simultaneously with HART is particularly valuable to Lowery. “This capability is extremely important when validating loops. We use the digital PVs to validate analog PVs on critical positioners. It just tells us what is wrong with the device,” he states. “And on critical loops, if the analog PVs and digital PVs don’t match up within a certain percentage of each other, we alarm that loop and have operators investigate the actual valve position.”

BuCkeyes’ asseTs ManagedThe simultaneous analog-digital capability of HART fulfills one of the most obvious asset man-agement functions of HART-enabled automation—protecting equipment and keeping plants operating.

Of the 200-250 HART-enabled devices at the Mc-Cracken plant, an asset management system (AMS) monitors 40 of them. By the end of 2007, the AMS

Advertising supplement to CONTROL S- Advertising supplement to CONTROL S-

tale of two plants

“We have approximately 200-250

hart-enabled devices. this plant

Wouldn’t operate Without hart.”

will monitor 180-200 HART devices, Lowery says. “The asset manager monitors and tracks device faults for all HART-enabled devices. Types of device faults—anything you can think of,” he explains.

Overall, diagnostics are much improved, he notes. “Our asset manager package tracks faults that occur in HART devices through our DCS. Small items, like a positioner losing its zero position are now caught early and repaired,” Lowery says. “But without that asset management software, the problem might have never been corrected because it wouldn’t have been seen until complete device failure.”

BIoTeCH’s dIgITal- analog FuTureWhile the university’s experience with HART is more traditional, Genentech’s attraction to HART focuses on the protocol’s availabil-ity and innovative use at the Vacaville’s CCP2 facility. There, the company is implementing HART with 15% of the I/O.

“There are a lot of instrumentation manufacturers that offer HART-compatible products,” says Kerls. That availability plus a huge installed base makes HART a proven technology, he adds. “This is tech-nology that’s going to continue to be supported and developed. It uses the same 4-20mA wiring you’d use in traditional I/O, so there’s no steep learning curve.” He emphasizes this means reduced installation costs and reduced risks during startup.

Kerls adds that HART’s simultaneous analog and digital communication capability is a key attribute to the protocol’s value. “We’re able to implement HART communication over familiar 4-20mA twisted-pair signal cable, a proven and simple in-stallation method,” he says. “There are no address-ing schemes, network-sizing concerns, or special communication requirements to deal with.”

Genentech reports it also chose HART because its Honeywell instruments are HART-enabled. “So, we need no new infrastructure other than a new database server. The information is seamlessly inte-grated throughout the I/O, DCS controller, and the process data server,” Kerls says. In other systems, however, he believes multiplexers or other devices are needed to pick up digital signals. “With the Honeywell system, HART data is tightly integrated, so information is available right in the DCS.”

Kerls adds it’s important that Genentech can use any vendor’s flow or temperature devices as long as they’re HART-compatible. “If a device that we wanted had a HART option, we asked for it. For almost all devices, the HART capability was free from the vendor. But even if the HART option cost money, we still purchased it,” he recalls.

reMoTe ConFIguraTIon nearBy The ability to view instrument health is available in Genentech’s DCS without added hardware.

“We’re able to view/modify instrument con-figurations without interrupting process monitor-

ing,” Kerls explains. Genentech chose HART because buses such as Profibus, Foundation fieldbus, and DeviceNet had issues concerning their design, which is different from HART

and its 4-20mA capability. “ It takes more time to get other buses operable. We get the most benefit via HART,” he adds. Number one on Kerls’ list of HART benefits is an enhanced view of the instru-ments., which includes status, alarming informa-tion, and remote configuration.

Genentech also values the HART protocol’s re-mote capabilities. “The biggest bang for the buck is remote configuration and monitoring. HART won over all the other buses,” Kerls asserts, “be-cause it provides remote capabilities, installation simplicity, and met our requirements.”

Remote device setup and configuration is essen-tial because it allows Genentech to easily backup instrument configurations using a central data-base. The firm also can make changes to instru-ment configurations from a controlled database compliant with 21 CFR Part 11 (Title 21 Code of U.S. Federal Regulations Part 11: Electronic Records; Electronic Signatures from the U.S. Food and Drug Administration). Kerls adds this was possible without relying on handheld devices or technicians’ hand-written notes.

overall ConFIguraTIon Is CruCIalCentral configuration management is another area where Genentech will use the HART protocol. The company will use a database to capture, view, verify, test, and backup instrument configurations for more than 1,125 instruments during the startup of CCP2.

S-10 Advertising supplement to CONTROL

tale of two plants

“managing our instrument config-

urations reduces our regulatory

risk and our risk to product.”


“HART protocol with the online configura-tion-management database eliminates the need for a time-consuming paper process,” says Kerls. “It probably saves an hour off each calibration which basically is a half a person-year saved under normal operations. In initial documentation of parameters and startup, this may also save 3,000 hours. These are very conservative estimates.”

Compared to traditional I/O, Genentech can use HART to diagnose an instrument just by opening a view, rather than sending someone out to the device’s location. “If anything goes wrong with that device, it’ll notify the operator though a DCS alarm,” he adds.

Genentech reports that HART-associated work at CCP2 is enabling more efficient man-agement of instrument configuration. “Once we get this up and running, part of corporate automation engineering’s role is to disseminate information about the project throughout the corporation,” says Kerls “This also means edu-cating our maintenance group on our systems’ capabilities and developing efficient processes to leverage HART-enabled technology.”

Another benefit includes building the corpora-tion’s instrument configuration-and-calibration Standard Operating Procedures (SOP) on how to use the HART protocol and Genentech’s configura-tion management database.

“We’ll continue to minimize the time required to perform configurations and calibrations,” Kerls emphasizes. “You can put these technologies in, but if you aren’t educating your lifecycle group—maintenance and the local automation engineering group—to use them, then the corporation never gets the full benefit.”

CoMPlIanCe ProTeCTs dosesDiagnostics. Maintenance. Regulatory compliance. SOPs exist for them. All are taken seriously at CCP2, and HART plays a crucial role here, too.

“Our HART devices are installed as part of an 8,500-I/O DCS. Any device errors or alarms will automatically be available to the operators/techni-cians,” explains Kerls. HART allows Genentech’s staff to receive device-specific alarm values, which reduces troubleshooting time. “On a new plant, we don’t really know what the issues will be,” Kerls says, “but we expect that we’ll find them quicker, which goes directly to the bottom line. Our HART implementation will ensure that the current con-

figuration is always correctly backed up.”And, if an instrument needs replacement, HART

simplifies this process. “We download the backed up configuration for the old instrument from our HART configuration management database. These parameters upload to the new device through the analog I/O card,” says Kerls. “Effectively manag-ing our instrument configurations reduces our regulatory risk and risk to product.”

Risk to product usually means producing less at poorer quality. “If a critical instrument is involved and you can’t prove you had adequate control over properly configured devices, it could lead to regulatory action and/or a recall of the entire batch,” says Kerls. “You’d have offline analytical measurements so you might not lose the batch, but you might spend a lot of time defending it.”

TIPs FroM THe FIeldCorrect monitoring, particularly with HART-enabled instruments, also concerns Lowery, who offers tips for users. “HART device diagnostics is only as good as the vendor’s device description (DD) file. The more detailed the DD file, the more diagnostics you’ll have,” he explains.

Lowery also suggests ensuring that the DCS analog I/O is HART-enabled. “Using a third-party solution to strip out and send HART data via a serial connection will likely prevent using HART digital PVs in a fast changing loop,” he says.

FuTuRe’s suRFACe Only sCRATCHed

Ohio State’s experience with HART was so positive that the power plant’s staff is examining tracking the drift of the analog PV compared to the digital PV. Also, there’ll be more use of HART device diagnostic faults in the control strategy, says Lowery. Ohio State also plans to evaluate using a field device manager (FDM) for configuring HART devices, rather than using HART communicators. “This will help us catalog devices. We’re told that if you replace a device, when you plug it in, the DCS will automatically give it its tag and other operating information,” he adds.

Overall, Kerls is even more optimistic about the role of HART in Genentech’s future. “If HART works well at CCP2, we can just roll it out to other Genentech plants,” he says. “If you use HART, you’re going to save big time in lifecycle management because the installation cost is no more than if we installed traditional I/O systems.”

tale of two plants

HART Champions Stay CompetitiveReliable communications via HART bring large gains

to many process projects

The HART Communication Protocol pro-vides the toolkit for process champions. It imparts this through a global installed base

of more than 20 million HART-enabled devices. This is extraordinary because HART debuted just 20 years ago, and only became an open standard in 1990. Not surprisingly, all major industrial-auto-mation suppliers support HART. Pick any process measurement and control application, and HART is there. The protocol assists in chemical production, water desalinization, as well as pulp and paper, natural gas and steel production. It helps manage wastewater facilities. And it’s in OEMs’ pressure and temperature metering devices.

So, why does HART enjoy such popularity? End

users say it’s simple, reliable, robust, flexible, easy to use, rugged and cost-effective. They also know that HART keeps their businesses competitive by providing simultaneous analog and digital com-munications, as well as interoperability.

We asked several end-users how they’re using HART to keep their plants competitive. They report that they’re gaining efficiencies and sav-ing money by better using their installed assets, and using the intelligence in their HART-en-abled field devices. By tapping into this informa-tion, they’re now working smarter and keeping competitive. The investments in many cases are small and the returns are big. Creative? Yes! Difficult? No! The key is just getting started!

Advertising supplement to CONTROL S-15

hart users win big

Appleton pAper tArgets better Asset mAnAgement

To win in the paper-coating game, pulp-and-paper producer Appleton Paper implemented HART in an addition/upgrade to a coating machine in its facility in Appleton, Wis. The company installed more than 100 HART-enabled flowmeters, control valves, and pressure sensors.

The papermaker targeted several criteria for the project. 1) Minimize costs for hardware, software, training, spare parts, etc. 2) Find a simple, robust system to inform staff about device health. 3) Use that system in other applications. 4) Get a database for configuration, tracking, troubleshooting, etc. 5) Obtain access to all instrument/device data.

“HART gave us the best opportunity to expand with the rest of our existing control systems at the lowest costs,” says Chris Van Sambeek, Appleton Paper’s control systems technician.

The ultimate goal was better asset management. Appleton uses HART via a leading supplier’s PLCs and a supporting supplier’s HART-enabled I/O system to link its smart instruments to Emerson

Process Management’s AMS package. Appleton enhanced its instrument-configuration capability and preventive maintenance with HART’s better troubleshooting capability. “So far, HART has been very effective,” says Sambeek.

Appleton also saved by installing and con-figuring fewer transmitters. “HART saved us roughly $40,000 on wiring alone with its ability to pull multivariable information from our mass flowmeters,” adds Sambeek. Using AMS for commissioning, Appleton also saved money and time by remotely configuring devices. HART technology saved another $10,000 or so because the company now needed 12 fewer pressure and 12 fewer temperature transmitters.

Sambeek says HART also improved opera-tions in other areas, including “better diagnos-tics; control-loop validation by pulling informa-tion into the PLC through the HART signal; increased plant availability; better product quality and utility; higher product yield; lower

operations-and-maintenance costs; and en-hanced regulatory compliance.”

Appleton succeeded with HART because the protocol was a better fit for expansion than other fieldbus technologies, adds Sambeek.

Finding a new HART smart card that the PLC system could use also helped Appleton. This card allowed the company to upgrade existing systems with minimal equipment and costs, says

Sambeek. “Most of our existing instruments are HART-enabled, and the HART cards used are compatible with our existing control systems.”

And, installing an OEM’s HART-enabled cards into Appleton’s control PLC platform allowed the paper company to use HART data in both the AMS and control systems. “HART provides addi-tional information not available to normal analog systems,” Sambeek adds.

hart users win big


V-F Controls reduCes troubleshooting time

V-F Controls Inc. in Mentor, Ohio, provides flowmetering systems to petrochem and steel-making companies, and to the district-energy market for custody transfer.

“Often, we assist in commissioning,” explains Jim Weinstein of V-F. “However, process conditions often aren’t as originally anticipated.” This means initial set-up of the instrument must be changed. “HART allows us to make changes in minutes, compared to hours if we used analog electronics.”

“Troubleshooting is a dream with HART. One of my first HART installations was a steam-flow metering system with differential-pressure, pressure, and temperature transmitters. The signals were sent to a flow computer,” he recalls.The transmitters were located on the piping near the ceiling of a high-bay building. “The customer had done the installation and wiring, and then called to tell us that the trans-mitters were indicating totally erroneous readings on the flow computer,” says Weinstein. “When we visited the site to troubleshoot, we agreed.”

“I thought this would be a good time to try out our new HART communicator. I hooked it up to the pressure-transmitter terminals on the flow computer, and established communication with

the transmitter,” says Weinstein. “It came back and said, ‘I am a temperature transmitter.’ ”

Without the HART-enabled devices, it would’ve taken longer to detect the bad setup. “It probably would have taken us an hour just to get 50 feet in the air to start troubleshooting.”

Weinstein says that HART adds loop-valida-tion functions to V-F’s applications like the ability to identify the transmitter at the end of the loop or driving a 4-20mA signal in the loop to verify proper response at a flow computer, chart recorder, or indicator. “These capabilities not only identify proper wiring terminations, they help us find poten-tial ground-loop issues and configuration errors in the transmitter or secondary electronics,” he states.

Weinstein’s a longtime HART fan. “HART is simply the only way to go for quick start-up, re-ranging, and troubleshooting,” he says. “The fact that it is a standard is most important when systems involve different vendors’ products.

“I’m not aware of any standard for digital commu-nication on a 4-20mA loop. As proprietary protocols fall by the wayside, more instrument manufacturers jump on the HART bandwagon. Why carry two or three communicators, when you can carry just one?”

persiAn gulF beComes drinkAble

The Saline Water Conversion Corp.’s (SWCC) Al-Jubail Phase 1 desalination and power plant was built on the Persian Gulf in 1982. The facility has six 60-megawatt power plants and a desalina-tion plant. A recent re-instrumentation project involved adding more than 2,000 HART-enabled devices from various manufacturers.

“Despite the size of this mega project, HART Communication helped us to the core,” says T. Veeresh Prasad of Yokogawa Engineering Asia. “HART also achieved best resolution and accu-

racy of the data, compared to the old devices that were in place for the past 20+ years.”

Prasad also appreciates that HART technology’s analog and digital communications are simultane-ously available. “Analog communications helped because of our fastest turnaround time require-ments,” says Prasad. “Digital helped quickly cali-brate and troubleshoot issues, including control-valve-positioner feedback.”

Something else that worked best for the project was HART technology’s response time at the host


hart users win big

system. “In terms of asset management, all the de-vices couldn’t give enough information to the host system,” says Prasad of the plant’s pre-HART days.

The protocol’s interoperability also allowed SWCC to integrate a Yokogawa’s Plant Resource Manager (PRM) asset management system, using

HART-compatible input/output (I/O) cards. The staff now uses PRM to crosscheck status. The re-sult? “HART is a very reliable platform for fastest response requirements of control and automation/safety-instrumented systems. It will compete with all other buses, all the time.”

sewers sAFer in wisConsin

The Milwaukee Metropolitan Sewerage District (MMSD) recently installed more than 200 level trans-mitters with HART interfaces in manholes. The new instruments were needed because the former level instrumentation wasn’t temperature compensated.

HART technology’s analog functions allowed an intrinsically safe barrier and installation calibra-tion in these explosion-proof areas. “The collec-tion-system manholes are typically entered yearly for calibration checks,” explains Eugene Moe, senior instrumentation and control engineer for Earth Tech Inc., Sheboygan, Wis., which jointly manages MMSD’s operations. “The result is an

installation that reduces time to calibrate the instrument, and eliminates the need to enter the manhole, unless the unit fails.”

“It’s not critical that the signal and calibration be available at the same time,” he explains. “But the dual functionality allows seamless operation of the system while the instrument is being inter-rogated and updated.”

Moe asserts that using HART-enabled devices saved money for MMSD, and adds those savings, coupled with the technology’s flexibility, reliability and field ruggedness, are why HART devices are used throughout Milwaukee’s sewage-treatment system.

eAstmAn ChemiCAl eAses the pressure

At Eastman Chemical Co.’s operation in Longview, Tex., pressurized tanks may have an allowable working pressure of 63 psig, which may be 10 times more than the span of the pressure transmit-ters. According to Josh Lowery, electrical engineer at Eastman Chemical, pressure variations in those tanks can cause problems. On startup, one tank’s pressure shot up, and popped a relief valve. A solu-tion using HART technology includes only one transmitter, rather than two as required before.

“We use the HART signal to read the actual value at the cell, and so read the full range of the transmitter,” says Lowery. This means operators can determine the actual pressure without re-span-

ning the transmitter. “We can strip the HART sig-nal, and get full range from transmitters in which the scale has decreased,” he says. “When we have upsets where the process went out of the expected range, we can capture the actual reading from the HART signal.” HART’s remote-configuration ca-pability has improved operations at the Texas fa-cility. “HART saves us the time we used to spend going to and from the instrument,” Lowery says. “More importantly, hazardous-area work requires many more permits. Hooking up with HART in the control room is much easier.” Remote configu-ration also allows Eastman to verify field wiring from the control room.

AustrAliAn steelmAking glitChes VAnish

Australian steelmaking giant OneSteel’s Whyalla SteelWorks in South Australia annually produces approximately 1.16 million metric tonnes (1.30 million tons) of steel.

In the electromagnetic stirrers at this facility, On-eSteel uses a major vendor’s calibrator to reprogram its HART field instruments and control elements. OneSteel chose HART technology for a new ana-log/digital interface because older systems caused

problems. “I read about the HART system and its ef-ficiency, so I pitched the idea to my manager,” recalls Jeremy Pereira. “And, well, here we are.”

Fully functioning means more efficiency. Every sys-tem can be monitored and adjusted remotely, adds Pereira. “It doesn’t have anywhere near as many glitches as our old system.” That’s a blessing, he says, because it requires fewer technicians. “So, it definite-ly saves money and, more importantly, time.” n


Users Want Suppliers’ HART Solutions on Their Teams

End-users implement suppliers’ HART-enabled tools to operate their businesses better, faster, and more simply. This is the

essence of what keeps them competitive.

Besides the benefits HART gives end-users through approximately 20 million in-stalled devices, its success also comes from

its partnership with suppliers of HART-enabled technologies. These suppliers include the world’s major control-and-instrumentation vendors, such as ABB, Emerson, Honeywell, Invensys, MACTek, Magnetrol, Moore Industries, ProComSol, Sie-mens and Yokogawa.

It’s no secret why end-users keep coming back to these and other suppliers—HART is a game-changing solutions enabler.

“We offer HART because our end-users world-wide expect us to support this capability,” declares Magnetrol International’s Dave Miller.

Eric Olson, ABB Automation Products’ business unit manager, adds, “HART is the most widely installed intelligent device technology today, and it continues to deliver significant benefits. So, of course, we remain a strong supporter.”

By implementing and using suppliers’ HART-enabled technologies, such as smart field devices, end-users know they can be more competitive. Suppliers’ smart-HART solutions lower operating costs by allowing quicker de-vice set-up and commissioning, and by enabling protocol interoperability via easy integration of multiple vendors’ technologies.

Suppliers’ HART technologies also improve process control, increase safety-instrumented-sys-tem (SIS) integrity levels, and smooth troubleshoot-ing and maintenance. These tasks also become less disruptive because HART grants access to 30-40

data items—such as process variables, device status, diagnostic alerts, loop current, and percent range—built into suppliers’ HART devices.

Another reason end-users rely on these sup-pliers is because HART provides simultaneous 4-20mA analog and digital channels or signals over one pair of wires. Analog gives the PV, while digital provides real-time connection to intel-ligent field devices and their information. This analog-digital combination also provides better control security and loop integrity.

HART SupplieRS Guide uSeRS To FuTuReT.S. Prasad Raghavendra, Honeywell Process Solution’s product manager for HART solutions, believes two key improvements will drive future growth. The first is HART 6. Its protocol revisions will offer better support for multivariable devices and actuators, more device and variable-status in-formation, and some new and extended commands.

Enhanced electronic-device-description language (EDDL) is the other advance fueling growth, says Raghavendra. By expanding device description language (DDL) capabilities, EDDL establishes a new industry standard for advanced visualization of intelligent-device information, while maintain-ing DD technology’s integrity.

SmART deviceS GeT SmARTeROne recent upgrade involves Emerson Process Management’s Version 8.4 of its DeltaV system software. It uses standard HART device-status information to generate Emerson’s PlantWeb alerts

Team harT scores

for any HART-enabled device. This gives end-users access to the predictive-diagnostic functionalities in those devices. Doing this can prevent abnormal plant operating situations and enhance smart SIS.

HART fully integrates with the analog signal, and allows end-users to adopt it at their own pace and within their budgets, adds Jim Cobb, marketing director of Emerson’s Rosemount Division. “HART instruments allow us to provide cost-effective in-novations with a technology that isn’t disruptive to customers’ operations and maintenance practices.”

Likewise, Moore Industries’ HIM HART loop interface and monitor is another innovative tool that provides process and diagnostic information that would be otherwise unavailable with smart multivari-able transmitters and valves. All an end-user has to do is install HIM into a critical loop.

“Smart/HART multivariable transmitters sense multiple process variables,” says Steve Todd, Moore’s corporate marketing director. “These transmitters perform an internal calculation to derive a measurement, such as mass flow.” Next, the transmitters send the process vari-able to control systems via a 4-20mA signal, but Todd reports that, without HART-based control systems, end-users can’t continuously monitor non-primary variables used to make the calculation.

Meanwhile, Honeywell’s intelligent HART tech-nology, such as its Experion Process Knowledge System (PKS), also makes end-users more competi-tive. “This is the first control system to offer I/O with native HART 6.0 support,” says Raghav-endra. “It’s also the first system to fully adopt the HART Communication Foundation’s (HCF) Smart Device Configurator Model 625 (SDC-625) reference host technology.”

Other smart technology that makes HART inte-gration easier comes from ProComSol, which now offers HART-enabled, device-configuration software. DevCom2000 smart device communicator is based on SDC-625. This HART-compliant host software accesses all HART DD features and functionality, says Jeffrey Dobos, president of ProComSol. “This includes monitoring and editing device variables, and executing all device DD methods,” he adds.

Other new additions to HART’s smart toolbox are Honeywell’s HART 6.0-certified pressure

products released in September. “More products will follow before year’s end,” explains R. L. “Rick” Gorskie, senior product marketing man-ager for Honeywell’s Industrial Measurement and Control (IMC) pressure/temperature products.

compeTiTive ASSeT mAnAGemenT Besides these advances, HART technology still needs to be configured. Consequently, configura-tion tools also keep end-users coming back to suppliers of HART-enabled technology. These tools make it easier for end-users to integrate HART into operations. And, as these tools become easier to use through suppliers’ upgrades and new systems, end-users get more out of their HART-enabled systems.

“As HART data becomes more integrated into control and asset-management systems, Yokoga-wa continues to enhance the powerful features in our flow, temperature, pressure, and analyti-cal devices because we know there’s an easy way to maximize these additional capabilities,” says

Hoag Ostling, chief application engineer for Yokogawa Field Instruments. Yokoga-wa’s HART solution includes integrated HART I/O modules

in its CS3000 production-control system and HART-compatible field instruments.

When end-users integrate these with Yokogawa’s Asset Excellence solutions, which provide the foun-dation for comprehensive, condition-based mainte-nance strategies, users gain the intelligence inherent in protocol-enabled field devices.

Because asset management can occur remotely, suppliers also are helping end-users integrate that technology into operations. “The initial customer benefit for remote configuration via HART has expanded in recent years with the addition of asset monitoring for improved predictive maintenance,” says ABB’s Olson. This has helped ABB’s end-us-ers improve productivity and lower maintenance costs, he adds. ABB has increased its Smart/HART capabilities through HART-multiplexer support for installed systems, and with new HART-based, con-figuration-and-calibration handhelds that support ABB and non-ABB devices to a device-specific level.

Because remote connections, including wire-less, require modems, end-users can implement two HART-compliant devices from ProComSol,

Advertising supplement to CONTROL S-21 Advertising supplement to CONTROL S-21

Team harT scores

It’s no secret why end-users come

back to these supplIers—hart Is a

game-changIng solutIons enabler.

including its universal serial bus (USB) HART modem, HM-USB, and its wireless Bluetooth HART modem, HM-BT-BAT.

Another supplier providing access to HART data is MACTek with its Viator RS232 and USB HART interfaces. These HART-compliant technol-ogies allow a host PC to communicate to a HART-enabled device made by any supplier, according to Thomas Holmes, MACTek’s president.

“What this means to end-users is that these modems work the first time,” Holmes emphasizes. This capability means end-users can communicate with their HART-enabled devices without worrying about the modem’s reliability or capability when serving in an industrial environment, he adds.

In response to today’s trend of connecting smart devices via PCs to configure and manage intelligent device lifecycles, Holmes reports that a PC-HART-modem combination lowers costs, and makes device configuration easier, especially with many parameters. Another advantage of this combination is its improved use of device capabilities that suppli-ers build in to produce and maintain database con-figurations, Holmes notes. These capabilities may be used, for example, in radar tank-level applica-tions to display the shape of a tank. End-users may use these data to diagnose device health, validate operations, and to replace instruments.

eddl AidS opeRATionSSuppliers also offer new solutions involving HART’s EDDL enhancements, which fit into Smart/HART technologies, and integrate easily into end-users’ industrial operations. These include improved user interfaces with support for menus, windows, tabs and groups, as well as added graphic support for graphs, trends, charts, and dial indicators.

EDDL further standardizes the user interface for managing intelligent devices, and eliminates the need for Windows resource files, supplemental files, and other modifications, previously required by some as-set-management applications.

In fact, Invensys Process Systems’ Foxboro Au-tomation unit recently announced plans to embed HART’s SDC-625 technology into Foxboro’s process automation system. “This HART technol-ogy will enable customers to take advantage of the new enhanced EDDL,” says Betty Naylor-McDe-vitt, Foxboro’s marketing director. Automation and control device vendors can program sequential interactive steps for calibrating and starting up field devices in EDDL, she adds. And enhancements to EDDL let device vendors define user interfaces for plotting, trending, and storing device data.

To make EDDL more available through HART and other fieldbuses, Emerson and Siemens Auto-mation & Drives announced a new technology-sharing effort in July. They’ll expand some systems to give end-users more access to HART and other fieldbus standards. Siemens will add interfaces to its Simatic PCS 7 process-control system and its Simatic process device manager. Emerson will expand its DeltaV and Ovation control systems and its asset management system (AMS) suite. The two companies plan to release their first products in this cooperative effort in mid-2007.

Through all of these new technologies and upgrades to existing ones, suppliers have helped HART become widely accepted by global custom-ers. “HART’s efforts to take this ‘communication standard’ to the next level with Release 6.0 shows its drive to remain one of the world’s premier commu-nication options for the process control industry,” adds Honeywell’s Gorskie. n


Team harT scores

affordable dd based configuraTion using Your Pc

ProComSol, Ltd designs and manufactures both the hardware and software needed to perform complete HART device configuration and monitoring using your PC. DevCom2000 software uses the registered DD’s from the HART Foundation, allowing full access to all device parameters, including Methods. The HM-USB USB HART modem and the HM-BT-BAT Bluetooth HART modem offer significant cost savings and productivity benefits. Units meet industry standards for USB, Bluetooth, and HART connectivity. Order this affordable solution online using our secure website.

Procomsol, ltdProcess Communication SolutionsTel. 216.221.1550 • Fax 216.221.1554 • www.procomsol.com • [email protected]


Some tools sit in your toolbox and are rarely used. Other tools are attached to your tool belt and used daily. In

some cases we overlook the added benefits and capabilities that a tool can provide because, well, we just don’t think of it that way. Do you think of HART as a tool in your toolbox or one that is on your tool belt and used daily?

Remaining competitive in today’s global economy is no small task. We need every possible resource and asset maximized to provide that competitive edge needed to survive. We spend time wishing for things we might like to have and in reality the wish might be sitting right in our toolbox.

HART Communication is one of those tools that might be in your toolbox but needs to be moved to your belt! When you open it up, you will find a powerful, easy to use and cost-effective field communication protocol solution that lowers operating cost, increases plant availability and helps with regulatory compliance. Based on the industry standard 4-20mA, this robust, low-risk protocol is the right tool for the job.

In this 5th annual HART supplement, we present ideas, information and testimonials on using the POWER of HART and getting more from what you’ve got installed. HART is the tool you can use to make your plant run more efficiently by putting it to work with your plant automation, safety and asset management systems—maximizing your assets. As pointed out in this document, HART-enabled projects are easy to find, install, use, and to justify. In most cases, the pay back is quick and benefits significant.

Field instruments are becoming more intelligent and more open with advanced functions and diagnostic features that are powerful tools to achieve corporate objectives. Enabled by HART Communication, today’s control systems and I/O interfaces can painlessly integrate the intelligent in-formation from these devices and put it in the hands of plant personal to maximize and optimize the operation. New tools & technology enhancements like the DD-IDE development environment, HART 6 and the enhanced Device Descrip-tion Language contribute to HART’s ability to be one of the most useful tools on your belt.

We will help you identify big opportunities when you move from part-time to full-time communications with HART-smart field devices and the integration of diagnostics

and other intelligent device information into the control, asset management or safety system. This supplement is loaded with useful tips on how to identify projects that provide a high ROI and significant value to your operation.

In this supplement, we review how small and gradual in-vestments will enable plants to avoid unplanned shutdowns and unnecessary maintenance costs. Optimizing your assets

and increasing the efficiency of your staff contribute to making HART a low-risk and cost-effective decision—one that is easy to deploy and to justify. Finally, we identify the benefits of the enhanced Device Description Language and wireless HART. We continue to invest in HART technology to make sure it addresses your need to remain competitive.

Regardless of the make and vintage of your control system or the type of HART-enabled field devices you may already have installed, there are many solutions available from the 160+ HART Communication Foundation member companies that can help you put the POWER of HART to work in your plant.

Get more from the HART devices you’ve got working in you plant. Why? Simple—in order to become or remain competitive. You need to think of HART as the tool you use daily to solve critical problems or better yet, identify and avoid them before they become problems.

Getting more information is as easy as contacting your device or system suppliers or by visiting www.hartcomm.org. The HART Communication Foundation is here to edu-cate, train and assist you to get more from what you’ve got and to UNLEASH the POWER of HART.

Is HART on your tool belt?

Ron HelsonRon Helson, Executive Director, HART Communication Foundation512-794-0369; [email protected]

HART FORWARD

Use The Tools You Have

“HART Communication is one of those tools that might be in your toolbox but needs to be moved to your belt!”


It’s ironic; in their endless quest to reduce costs while increasing output and quality, many manufacturers have been ignoring one of the

most potent technologies for achieving those ends. Not only that, it’s a technology in which most of them already have made substantial investments!

The technology? HART. For years, instrument and systems vendors have been incorporating HART communications capabilities into field devices, enabling those devices to send digital information, including diagnostic information and secondary variables, to host systems. (The HART Communication Foundation estimates that more than 15 million HART-capable devices are installed worldwide.) But with the exception of maintenance personnel tramping into the field with handheld communicators to configure instruments, most users have left HART’s benefits untapped.

Those days are coming to an end, however. Instru-ment vendors are providing open access to their de-vices through readily available device descriptions; control systems providers are including HART I/O hardware in their products as well as asset manage-ment software; and many vendors are marketing products that enable the owners of legacy, analog-only systems to access the power of HART.

So, with HART data more accessible and poten-tially useful, key questions users face are:

What’s the best way for my company to access that data?

How do we identify applications in which we can use HART to generate business value?

A Brief HistoryHART, an acronym for Highway Addressable Re-mote Transducer, was developed in the late 1980s and became publicly available in the early 1990s.

Unlike other recent field communications pro-tocols, such as Foundation Fieldbus and Profibus, which are totally digital, HART is a “hybrid” analog/digital technology. An instrument’s primary variable is transmitted via the industry standard analog 4-20 mA signal, but up to four secondary variables and device diagnostic information can be digitally “piggybacked” on it. As a result of these digital communications capabilities, users have access to extensive data from their devices, including diagnostic information and -- in the case of some instruments -- multiple process variables (i.e., a pressure transmitter also might be capable of providing temperature data).

In 1993, the HART Communication Founda-tion (HCF) assumed ownership of the protocol and responsibility for administering and maintaining it. As part of its mission, HCF tests systems and devices for HART compliance and provides educa-tional services to vendors and users.

In HART’s early years, many instrument vendors quickly adopted the technology, but the remote connectivity was complex due to the need for ad-ditional wiring and hardware, such as multiplexers. Sandro Esposito, Masoneilan’s diagnostic product manager, says this lack of seamless connectivity created “islands of automation” for the user.

Charlie Piper, fieldbus product manager for Invensys’ Foxboro business unit, agreed.

“There are more than 500 different HART

devices in the marketplace, and there’s lots of information you can get about their performance, such as when valve positioners are starting to wear out or stick,” he says. “But until recently no one had come up with a way for all the host vendors to have a user interface to do these neat things with everyone else’s devices.”

Today, however, most vendors make their Device Description (DD) files openly available. HCF maintains and distributes a library of hundreds of DDs that enable any HART host (e.g., control sys-tem, configurator, asset management system, safety system, etc.) to communicate with a vast array of field devices. That development is coupled with the development of comprehensive applications to monitor assets, such as Siemens’ Process Device Manager, Emerson Process Management’s AMS Device Manager, and Honeywell’s Asset Manager PKS. As a result, users now are able to access most – if not all – of their device information from a single screen, regardless of device manufacturer.

In recent months, HCF has developed new tools and technologies to make development of HART-compliant DDs easier. These include the new De-vice Description Integrated Development Environ-ment (DD-IDE), which is designed to streamline development, testing and maintenance of DDs and facilitate the creation of product applications with

People are realizing that HART is

capable of delivering many of the

same benefits as fieldbus.

HART VALUE


DD capabilities.“The DD-IDE supports the iterative DD devel-

opment style with a fast and efficient integrated tool set. Each step in the edit-build-test cycle is supported in a DD-aware editing environment,” says Wally Pratt, HCF’s chief engineer.

Also near completion is the Enhanced Device Description Language (EDDL) specification. EDDL gives vendors the ability to add new capabilities to

DDs while improving cross-platform compatibility and facilitating device set-up. (See details else-where in this supplement.)

HART-enabled instruments deliver greater value than ever before, says Dave Smith, manager of Yokogawa’s plant network technology center. “The processing power of the devices is increasing greatly,” says Smith. “Therefore, field instruments feature additional functionality, including diagnos-tic type functions, predictive functions and others.”

Jim Cobb, marketing manager of Emerson Process Management’s Rosemount Division, notes that users are increasingly aware of the capabili-ties of the digital field. “One of the reasons is that suppliers are better implementing features to use the capabilities of HART devices,” says Cobb. “Another reason, ironically, is that there’s been so much talk about fieldbus in recent years. People

are realizing that HART is capable of delivering many of the same benefits as fieldbus.”

Identifying High-Value ApplicationsIndustry experts are nearly unanimous that the greatest return on HART technology investment lies in the ability to continuously monitor the field instruments. Masoneilan’s Esposito notes that dras-tic reductions in maintenance staffs during the past decade have made automated monitoring of field instruments an absolute necessity in many plants. By being able to watch and track the condition of plant floor devices, maintenance and operations personnel can spot problems in the making and take action before they cause process upsets and unplanned shutdowns. Conversely, being able to see that a device is working well enables users to avoid unnecessary maintenance activities.

“If you have a lot of HART devices in your instal-lation, and you’re not monitoring them on a continu-ous basis, you’re missing a great deal of opportu-nity,” says Tom Holmes, president of MACTek, a manufacturer of HART modems. “There’s diagnostic information, alarms, alerts and confirmations of whether the analog signal is good or bad.”

Industry experts recommended a number of strategies to help users identify the most high-val-ue applications involving continuous monitoring.

Emerson’s Cobb suggests that plants go about taking advantage of HART gradually.

“One of the nice things about HART is that you can add its capabilities to your plant, loop by loop, and gradually take your facility from analog to a fully integrated HART plant,” says Cobb.

“I’d start with online monitoring of my most criti-cal assets. That’s where I’m going to get the most value from predictive diagnostics, such as being able to avoid unplanned shutdowns and prevent-ing off-quality products,” adds Cobb. “At the same time, I might start using HART to monitor other in-struments offline and gradually, as my maintenance budget allows, bring other assets online.”

Marcelo Dultra, vice president of sales and marketing for Smar International, recommends plant audits as a means of identifying areas ripe for improvement via HART. “They should do a full check of what equipment they have installed and what technologies they’re using. This kind of thing usually takes a maximum of two or three days,” says Dultra, who adds that Smar, as well as other vendors and consulting firms, provide such services.

Keys to HART value• Identify the most critical loops in your plant

first and begin monitoring them via HART on a full-time basis. Other less essential loops can be monitored offline periodically.

• An outsider can bring fresh perspective. So consider bringing in an outside consultant to help you identify areas where you can realize maximum benefit from HART-based solutions.

• Make a business plan to determine if the cost of incidents is higher than the cost of invest-ing in HART-enabled I/O.

• Employ a diagnostic tool to monitor loops and field instrument performance and iden-tify potential troublespots that could benefit from full time monitoring via HART.

• Take advantage of resources and training pro-vided by HART Communication Foundation.

• While HART is used primarily for equipment monitoring and configuration purposes, don’t overlook opportunities to use it in appropri-ate control applications.

HART VALUE


“It’s always good to get opinions from outside the plant, from people who have seen other operations. If you work a long period in your own plant, you miss some points that are important, especially when it comes to the technologies available today,” he adds.

Prasad Raghavendra, Honeywell’s product manager for all systems-related HART products, recommends that users review a history of process upsets and their causes to identify areas that are ripe for HART-en-abled continuous monitoring. “Make a business plan out of that to determine if the cost of incidents are higher than the cost for investing in HART-enabled I/O,” says Raghavendra. “That’s a fairly simple method that would clearly indicate whether it was worth it for the customer to make the investment.”

In some instances, he says, the benefits from in-vesting in HART will be plain. “For example, your plant could be having problems caused by simple incidents like sensor failures. If you’re simply relying on a 4-20 mA signal, the operator will see a local trip, but everything in that group of devices becomes suspect. This requires the operator to call maintenance and initiate what could be an exten-sive debugging process. With HART, however, if there’s a sensor failure, the device tells you that it’s the source of the problem, saving you time and resources in correcting the malfunction.”

“Processes that could benefit the most from this technology are those with a large number of re-mote-connected HART devices that can be brought in to a control system through a remote HART I/O,” says Eric Olson, a senior product manager with ABB. “This could include processes such as those in the oil and gas or wastewater treatment indus-tries, where there are many satellite I/O stations.”

Foxboro’s Piper recommends that users employ a diagnostic tool such as ExperTune’s PlantTriage, to monitor loops and field instrument performance and identify potential troublespots that could ben-efit from full time monitoring via HART.

HART can play an important role in refineries, mills and power plants that employ process safety systems. To maintain a system’s Safety Integrity Level (SIL) rating, safety system valves must be periodically tested to ensure that they will move if called upon in an emergency. Full-range tests can be conducted only during plant shutdowns, but these occur only every two to three years. However, by stroking a valve by as little as 10 percent, which does not disrupt a process, plants can ensure the reliability of their safety valves. A valve positioner has the ability, via HART, to con-

firm to operators that the valve actually responded to the movement command.

Robert Hotard, a product manager with instru-ment-maker K-Tek, also suggests that users take advantage of HCF’s expertise in planning HART-based projects. “The first thing I’d recommend to anyone interested in HART is to go to the Founda-tion’s website (www.hartcomm.org),” says Hotard. “There’s a lot of information there that’s available to everyone and explains in great detail how to use the protocol and the benefits that are possible. I’m currently writing some manuals for K-Tek prod-ucts, and in them I specifically reference the HCF website.”

Don’t Overlook Control OpportunitiesWhile most facilities use HART for applications related to device configuration and maintenance, users also should look for opportunities to use HART data for process monitoring as well. For example, in applications where conditions such as temperature, pressure and levels change relatively slowly, users can reduce the number of instruments they need in the field by acquiring multiple vari-ables from a single device. Hotard points to tank farms as being ideal sites in which to make use of HART for applications such as inventory monitor-ing. (see accompanying story).

In relatively small operations, users can set up modest, but effective SCADA systems that utilize HART technology, says Mactek’s Holmes. “You could continuously monitor up to eight points using a PC equipped with eight USB HART modems. That’s very do-able,” says Holmes.

“For software, you could use a dedicated data acquisition package such as Wonderware’s InTouch software, or something as basic as a Microsoft Excel spreadsheet. I think there are plenty of operations such as bakeries or small specialty chemical plants that can’t justify spending the money for a large con-trol system. But with HART input and a PC, you can build yourself a quick and dirty DCS,” he adds.

Liberate the Genie Having HART capabilities at your disposal, but not taking advantage of them, is like keeping the genie stuffed in the lamp. By carefully examining your facility, looking at the HART capabilities you already have, and carefully weighing the need for additional investments, you can take full advantage of opportunities for improvement.

HART VALUE


JUSTIFYING HART

Selling UP!Justifying HART Investments to Management

“A no-brainer!”“Mom and apple pie!”“So obvious, it’s barely worth

discussing!”These are some of the immediate responses

from systems and instrumentation suppliers and users when asked how maintenance and operations departments should go about justifying investments in HART technology to plant managers.

But a no-brainer to a plant maintenance manager may not necessarily strike the same chord with a senior financial manager. Consequently, personnel who want to start reaping the benefits of HART need to develop strategies that take into consideration the HART capabilities the facility already has (e.g., installed HART instruments, HART I/O, etc.), ad-ditional investments needed, and the benefits the company will realize from those expenditures.

The no-brainer attitude stems from the fact that most plants already have made substantial invest-ments in HART technology. So, say the experts, it only makes sense to put those capabilities to use.

“If you’ve bought 4-20 mA instrumentation in recent years, chances are good that it’s already HART-enabled,” says Prasad Raghavendra, a

systems product manager for Honeywell. “And if you’re considering buying new instrumentation, the incremental investment in buying HART-enabled devices rather than those capable of only 4-20 mA

A no-brainer to a plant maintenance man-

ager may not necessarily strike the same

chord with a senior financial manager.

• HART data integration with control, asset management and safety systems

• Systems communicate with HART devices “full time”– both 4–20mA and digital

• Systems detect impending problems and provides alerts

• Continuously validates control signal integrity

• Automatically detects deviation in device/system data

• Continuous device diagnostics

• Multi-Variable device data available to improve operations

Intelligent Field Communication ERP

CMMSHMI

Control

HART I/O

HART Field Devices

HA

RT

Da

ta


is extremely small. So it becomes easy to decide to go with HART without having to make a big case.”

If you’ve purchased your control system during the past few years, odds are good that it has native HART I/O, meaning you can bring the digital HART signal, including diagnostic information, secondary process variables, etc., directly into the system.

In addition, HART Communication operates over existing wires, so much of the physical infrastruc-ture you need already is in place.

Most plants, however, will have to invest at least a small sum in equipment and/or software to take ad-vantage of HART capabilities. These include HART multiplexers, which strip the HART digital signal from the 4-20 mA signal and route it to PC-based software applications equipped to accept HART in-put; and HART modems, which are PC I/O cards that enable users to communicate with devices via HART.

In putting together a case for those investments, maintenance and operations departments should stress to management the situations that won’t occur as a result of using HART. Specifically, HART will enable plants to avoid unplanned shutdowns and

unnecessary maintenance, particularly on valves.“You’re going to make your workforce more

efficient, because you can get them focused on working on the right stuff,” says Jim Cobb, market-ing manager for Emerson Process Management’s Rosemount Division. “This is especially true of the valve diagnostics. It’s probably the one that hits you right in the face.”

Being able to keep an eye on valve performance via HART and compare it against valve signatures will reveal to plants when the device actually needs maintenance.

‘If your current mode of maintenance involves shutting down every six months and checking valves, transmitters, etc., the use of HART may en-able you to reschedule and reduce those activities,” says Marcelo Dultra, vice president of sales and marketing for Smar International. “If you can show that a valve can run eight or nine months, you might not have to shut down every six months. There’s enormous value in that.”

In plants that employ safety systems, testing safety valves periodically is absolutely essential. Af-

Inergy, headquartered in Kansas City, Mo., is a major provider of propane and services to 600,000 customers. While most of its operations are in the Southern, Midwestern and Northeast-ern states, the company operates a natural gas liquids site in Bakersfield, Calif., that includes processing, storage and terminal services.

Propane manufactured at the facility is stored in bullet tanks, each of which holds 10,000 to 15,000 gallons of propane. It is critical for the company to monitor levels and temperatures in each of the containers, since propane expands as temperatures rise. If pressure increases too much, the company must vent gas into the at-mosphere and risk violating stringent California environmental regulations.

Ken Clifton, instrumentation and electrical su-pervisor at the plant, says personnel used to rely on sight glasses and “spinner” gauges mounted in the tanks to visually judge levels. “Our people would have to actually go out there and look at the tanks to determine the levels,” he says, add-ing that it was inefficient.

To improve the situation, Inergy decided three years ago to install field instruments in each

tank that would send readings on temperature and level back to Inergy’s control system. “We could have put separate temperature and level transmitters into each of 40 tanks, but that involved quite a bit of instrumentation and wiring. Instead, we purchased instruments from K-Tek, each of which was able to monitor both of those variables,” says Clifton.

The transmitters send 4-20 mA level read-ings back to the plant’s programmable logic controller equipped with a HART gateway and use a HART digital signal to communicate tem-perature and level information. Using the two readings, the system is able to calculate the level in each tank accurately and display it on the system’s HMI.

“With this system, we’re able to get two read-ings for the price of one, and it’s worked well for us,” says Clifton. “We’ve had a few minor problems, but none involving use of the HART Protocol.”

“In fact,” adds Clifton, “all the instrumenta-tion we put in this plant has the HART Protocol, because it makes troubleshooting easy for our instrumentation techs.”

JUSTIFYING HART

Inergy’s Bakersfield Plant Moves Gas With HART


ter all, the last thing you want is for a valve to stick in an emergency. Under IEC and ISA safety system standards, a plant system’s probability of failure on demand can be reduced by increasing the frequency of system testing. Increasing frequency once was impractical for many plants, since valves could only be tested during shutdowns. However, plants now can run partial-stroke tests in which a valve is moved only a small percentage of its full range, to ensure that it functions properly in emergencies. If the valve actuator is HART-capable, the device can confirm its actual movement to operators and maintenance personnel.

Even in terms of day to day safety for workers, HART can play an important role. Norit Americas manufactures activated and reactivated carbon at its plant in Pryor, Okla. The manufacturing process re-quires the usage of acid, coal, steam, burners and com-pressed air, creating a hazardous work environment. By replacing conventional analog monitoring devices with HART-capable devices, maintenance personnel are able to run diagnostics and perform calibration checks and even make adjustments from the safety of the equipment control room through the use of a handheld set. In addition, the plant recently installed an asset management system workstation in its maintenance building, allowing personnel to work on HART-capable devices without leaving the structure.

Fritz Geiger, a systems product manager with Siemens, notes that HART Device Descriptions enable users to store all or nearly all of their in-strument data in a single database, thus improving organization, reducing expenditures on multiple pieces of equipment and software, and making more efficient use of personnel.

“This provides high benefit for the user,” says

Geiger. “He may have thousands of instruments and has to keep all of those different ranges and param-eters updated. The best way to do that is to have all of the information available in a single database.”

Sasol, an international chemical manufacturer, can testify to the value and benefits of HART based on its use in its South African solvents opera-tions. In 2000, as part of the planning process for construction of a butanol plant, the company set as goals the detection of field instrumentation and valve problems before they could cause production loss; migration from run-to-failure maintenance mode to predictive maintenance strategies; a reduc-

tion in control valve maintenance expenditures; and improved change management.

Sasol saw HART-based asset management as the means for achieving these ends. Among the benefits the company realized through the use of HART-based asset management just in the past two years are savings of nearly $2 million on prevention of plant trips, the avoidance of unnecessary repairs, and detection of faulty or poorly optimized valve positioners.

Obviously, no two plants are alike, and results that each can achieve through the use of HART can vary widely. Based on their experience working with a wide variety of users, systems and instrumentation vendors have come up with a number of implemen-tation tips to consider and pitfalls to avoid:

“HART will enable plants to avoid unplanned shutdowns and unnecessary maintenance, particularly on valves.”

JUSTIFYING HART

Two Simultaneous Communication Channels

• 4–20mA channel—fast, robust & reliable

• Digital two-way communication channel

for device status, diagnostics, alerts, etc.

35–40 Data Items Standard in Every HART Device!• Device Identification• Calibration Data• Process Variables

• Diagnostic Alerts

Control System HART Transmitter

Analog12 mA

+4–20 mA

The HART Difference


Implement solutions gradually Emerson’s Cobb notes that HART can be effectively implemented gradually, by tiers, making it easier to budget investments over a long period. ”At the low end of investment, you can stay offline and simply monitor loops on a manual basis periodically. This can be done in the field with a handheld communicator or by hooking up a PC equipped with asset management software, including data on all your instrumentation,” says Cobb. “At the next level up, you can establish

continuous monitoring via a separate asset manage-ment system. And, beyond that, if your plant has invested in a control system with HART I/O, you can bring the secondary variables directly into it.”

Rely as much as possible on existing equipmentSteve Todd, marketing director for Moore Indus-tries, which manufactures HART multiplexers says, “We’ve found that customers that stand to gain the most from HART technology are the ones that can leave as much existing equipment in place as possible, yet still make significant, cost-effective process improvements. For example, if a customer wants valve position feedback at the control room, he can go the traditional route and run additional wiring back to the control room that provides this data. This gets expensive fast. A second alterna-tive, though, is for the customer to leave everything else alone, and install smart HART controllers on the existing valves. Then, extract the stem position data from the HART digital data using a HART interface instrument installed in the control room.”

Demand interoperability from vendors “While HART is a very open protocol, not ev-ery company subscribes to it,” says Honeywell’s Raghavendra. “Consequently, buyers should make sure from their vendors that the field device and/or system fully complies with the protocol as defined by the HART Communication Foundation. Customers also should encourage their vendors to register their devices with the foundation.”

Be specific about your goalsBe specific about how you want HART to meet your needs, advises John DuBay, instrumentation product manager for Meriam Process Technologies. “Predictive maintenance is a great story, but many end users aren’t sure what diagnostics they’re look-ing for. If you ask them about the specific diagnos-tic capabilities they’re interested in, they’re not always sure.”

Provide easy access to HART data To achieve the benefits of online configuration and diagnostics, operations and maintenance per-sonnel need to cooperate. However, that situation often is the exception rather than the rule, says DuBay. “Not many operators are eager to open up access to their maintenance crews because they’re fearful that devices could be reconfigured incorrectly or by accident.”

Know where the ROI is coming fromMasoneilan Digital Product Specialist Leo Hughes advises that users should not expect to get substan-tial maintenance-related ROI from new HART-enabled digital valves. “The big rate of return is on the existing valves,” says Hughes. “You can graph a valve’s performance over time and see that it plateaus at a high level of performance when it’s new. You want to know where’s the drop-off from that plateau, and how steep it is.”

Minimize scan time with multiple mastersIf you plan to use HART to continuously monitor your field devices, update parameters, and cycli-cally read additional values, make sure you have a suitable number of HART masters, says Siemens’ Geiger. “If you just have one master talking to 32 field devices, you’ll wind up with scan time of five or 10 minutes. You don’t want that.”

It’s about work processes, tooTechnology alone won’t deliver HART benefits if your workforce fails to alter its work processes. “If they continue to do everything in the same way, even after they’ve put in some of these HART connections and asset management soft-ware packages, they’re not going to get the pay-back that they should,” says Cobb. “They need to change their work practices to take advantage of the fact that the transmitters are delivering more, very valuable information.”

JUSTIFYING HART

“You’re going to make your work-force more efficient, because you can get them focused on working on the right stuff.”


FUTURE HART

HART to the Future!HCF turbocharges plant communications with Enhanced Device Description Language and Wireless HART

HART has been a mainstay of process automation for more than a decade, but don’t mistakenly equate its maturity with

stagnation.The HART Communication Foundation (HCF)

staff and its members have been working for the past several years on enhancements that will increase the HART protocol’s value to users. The fruit of those efforts will become evident during the coming months with the release of the new Enhanced Device Description Language (EDDL) and a wireless version of HART.

EDDL represents an “upgrade” to the DDL that has been an important component of HART Com-munications since the very beginning. Instrument vendors use DDL, a text-based language, to write Device Descriptions (DDs), which are binary files that identify their products to a host system and provide the system with their operating parameters. (DDs are analogous to driver files provided to PC users by the makers of printers, scanners and other peripherals. The driver allows the PC to recognize the device, configure it and control its operation.)

Organizations responsible for other digital field communications protocols, including Fieldbus Foundation and Profibus Nutzerorganisation (PNO), have adopted the use of DDL as well. In 2004, the International Electrotechnical Commis-sion designated DDL as an international standard.

As “smart” field instrument technology progress-es, suppliers embed more capabilities in them, including the ability to transmit information on additional variables, perform increasingly com-plex math functions, provide more sophisticated diagnostics, etc. As a result, configuring asset man-

“Wireless HART will improve their ability

to establish full-time digital connectivity

to field devices. It will lower the cost

to add points to a HART network, reduce

wiring and make sensing more

ubiquitous throughout installations.”

EDDL Benefits Device Suppliers• Covers all devices—from

simple to complex

• Efficient development of DD’s

• Operating System independent

• Stable EDD

standard

• Lowers devel-

opment and

support costs

Users• Universal tools for all devices

• Consistent look & feel

• Highly reliable and robust

• Safe operation

• Compatible with existing devices

• Protect investments

• Lower maintenance costs

• Lower training cost


agement and control systems to use this abundance of information has become a more complex task. Complicating things further is the fact that vendors must develop and maintain separate DDLs for every different host system.

To ease the burden on users and vendors alike, HCF, the Fieldbus Foundation (FF) and PNO have been working together for the past three years to develop an enhanced version of DDL that gives vendors the ability to add new capabilities to DDs while improving cross-platform compatibility and facilitating device set-up. More recently, the OPC

Foundation joined the development effort.Ed Ladd, HCF’s director of Technology Pro-

grams, says some vendors already have added EDDL capabilities to their products and adds that major systems vendors will incorporate it into con-trol systems starting early next year. To make their systems EDDL-capable, systems vendors must add an EDDL Host Service Module, which will be available from HCF, FF and PNO.

Among the most noteworthy improvements enabled by EDDL is instrument vendors’ ability to use DDs to dictate the look and feel of graphical

FUTURE HART

• Electronic Device Description Language (EDDL) is the most

installed and important digital communication descriptive

language in the manufacturing and process industries.

• EDDL is a text-based language used to describe the

standard and unique characteristics of field devices.

HART was the first protocol to implement EDDL - which

enables suppliers of HART-capable instruments to

define and document their products in a single, open

and consistent format. This format is readable by many

devices including handheld communicators, control

systems, PC’s and other process interface devices that

support DDL.

• Automation suppliers use EDDL to create Device Descrip-

tion (DD) files that provide a standardized method for

host systems to access and display valuable parameters

located in field instruments so that the full capability of

the device can be accessed via the protocol.

• EDDL is used to describe such parameters as device

status, process data measurements, device diagnostics,

multi-variable measurements and device configuration

information in a digital format. As applied in the HART

Protocol, this digital information is imposed on top of

the industry-standard process control signal of 4-20mA.

EDDL allows the control system to read and format this

information making it valuable to the user.

• Developed in a cooperation with Fieldbus Foundation,

Profibus and the OPC Foundation, the enhanced EDDL

extends the capabilities of Device Description Language

to provide an industry-standard solution for advanced

visualization of intelligent device information to main-

tain the proven integrity of existing DD technology

across all four communication technologies. Devices

conforming to HCF, FF, PNO and OPC specifications all

use EDDL as a means of interpreting device parameters.

• The EDDL enhancements provide new capabilities to

benefit users in taking full advantage of the intelligence

in millions of smart HART-enabled measurement and

valve actuator devices. The enhancements provide users

with more information about the connected device while

giving device developers the tools they need to provide a

consistent look and feel, regardless of the host application.

• The EDDL enhancements include improved data

visualization and display capabilities – like waveforms

and valve signatures, a standardized method to access

historic measurement or device performance informa-

tion and enhanced tools for high-level information

– such as algorithmic relationships for complex device

parameters - display and use in control systems.

• EDDL enhancements include an improved user interface

with support for menus, windows, tabs and groups and

added graphic support for graphs, trends, charts and

dial indicators. The enhanced EDDL further standard-

izes the user interface for managing intelligent devices

and eliminates the need for Windows resource files,

supplemental files, and other DD modifications previ-

ously required by some asset management applications.

• The new EDDL enhancements enable users to interact

with their intelligent devices in new ways. Graphs,

charts, and calculations assist in the configuration of

devices including complex instruments such as digital

valve controllers, radar level gauges and multivariable

meters. The enhancements also support storage of

historical data from field devices for troubleshooting

and diagnostics.

EDDL Enhances HART Communication


FUTURE HART

interfaces to instrument information and set up, regardless of host platform.

“Using the current DDs, device attributes show up in a hierarchical tree,” says Ladd. “But with the new interface options and graphical capabilities, device suppliers create actual windows that enable users to see all of the pertinent information about

intelligent instruments. And, with the exception of things like colors, fonts, etc., that data will appear the same way on System X, System Y or System Z.”

Because vendors will not have to develop or maintain DDs for each host system that commu-nicates with their field devices, development and maintenance of device description files should be far less complex, he adds.

EDDL also will enable the incorporation of graphical elements, such as valve signatures, x-y graphs and bar charts, directly into the displays, eliminating the need for separate applications to display the data, says Ladd.

The enhanced DDL also allows persistent stor-age of data related to field devices. For example, users will be able to store multiple valve signature files generated by DDs and compare them to their valves’ current states, enabling users to more easily and quickly evaluate each device’s performance and whether maintenance is necessary.

EDDL also allows vendors to include in DDs instructions to host systems to execute advanced math functions that provide users with important information about the status and operation of their instruments.

Wireless HART represents the other imminent improvement to the HART protocol. Today, HART enables communication of a device primary value over standard twisted-pair wiring, using a 4-20 mA signal, while secondary values are digitally “piggybacked” on the analog signal via Frequency Shift Keying or Phase Shift Keying. With Wire-less HART, the primary value may still be carried via wiring, but users will be able to use a wireless

signal either to supplement or replace the wired transmission of digital data.

HCF’s Wireless HART Working Group, compris-ing representatives of numerous instrument and systems providers, began development of the Wire-less HART specification late last year and set March 2006 as the goal for completion of the specification, says Kelly Orth, distinguished technologist with Emerson Process Management’s Rosemount Divi-sion and leader of the working group.

“HART is a very lightweight protocol, so it is relatively simple to ‘tunnel’ HART messages inside wireless data packets,” says Orth. “At this point, we’ve generated a list of almost 50 requirements of how we want a Wireless HART system to behave.”

Orth estimates that only 5 to 10 percent of users who have installed nearly 15 million HART-enabled devices use anything more than their 4-20 mA analog capabilities to communicate with higher level systems. As a result, most users are missing the opportunity to capture data that can vastly improve their operations and maintenance capabilities.

“Wireless HART will improve their ability to establish full-time digital connectivity to field devices. It will lower the cost to add points to a HART network, reduce wiring and make sensing more ubiquitous throughout installations,” he says.

The Wireless HART Working Group is consider-ing a “mesh network” architecture for the protocol to deliver reliable communications. Unlike point-to-point networks, in which all nodes communicate directly with a line-of-sight “base” station, mesh networks allow nodes to communicate with one another, establishing ad hoc, redundant paths to the base.

“This improves reliability,” says Orth. “If a par-ticular path is blocked, there are other ways for the message to get through. Mesh networks also scale well. You just add more repeaters or routers without having to add much power. Also, the bigger a mesh network is, the more reliable it is, because more redundant pathways are automatically created.”

Point-to-point networks are really just a subset of mesh networks, so the Wireless HART solution will cover these applications as well.

As part of the development of Wireless HART, the working group is coordinating its activities with other industry wireless organizations, including the ISA SP100 Wireless Committee, to ensure continu-ity and uniformity with wireless standardization efforts currently under way.

“Some vendors already have added EDDL capabilities to their products and major systems vendors will incorporate it into control systems starting early next year.”

POWER. For centuries peo-ple have tried to harness,

create and control it. In today’seconomy, the ability to use thepower at your disposal is thename of the game. Corporateobjectives typically include: low-ering cost, increasing availability,

improving operationsand optimizing assets.Sound familiar?

Field instruments arebecoming more intelli-gent with advancedfunctions and diagnosticfeatures that are power-ful tools to achieve cor-porate objectives.Enabled by HART Com-munication, today’s control systems and I/O interfacescan painlessly integrate the intelligent informationfrom these devices and put it in the hands of plantoperators to maximize and optimize assets.

In this 4th annual HART supplement, we presentideas, information and testimonials on using thePOWER of HART and putting it to work with yourplant automation, safety and asset management sys-tems for maximum benefit. As pointed out in thefirst article, HART-enabled products are easy toinstall, easy to use, and easy to justify. The pay backis quick and within your grasp.

The article “New Value from Your Asset Data” iden-tifies big changes that have occurred concerning real-time communications with HART-smart field devicesand the integration of diagnostics and other intelligentdevice information into the control system. There aremany ways to get and use the HART data in your con-trol systems–the key is to start today! Finally, the arti-cle “Ready for HART? Pick a High Value Project toStart” provides valuable tips from users of the technol-ogy on how to maximize your investments.

Regardless of the make and vintage of your con-trol system or the type of HART-enabled fielddevices you may already have installed, there aremany solutions available from the 150+ HARTCommunication Foundation member companiesthat can help you put the POWER of HART to workin your plant.

HART is the easy, low-cost, low-risk and high-

value field communication solution that mostlikely is already installed in your plant. Put it towork, get your control system in continuous con-tact with the intelligent capabilities of your smartfield devices—Use the POWER and see whatHART can do for you!

Getting more information is as easy as contactingany of your device or system suppliers or by visitingwww.hartcomm.org. The HART CommunicationFoundation is also here to educate and help you toUNLEASH the POWER of HART.


hartforward

Get Connected with HART

Ron Helson,Executive Director

HART Communication Foundation512/794-0369; [email protected]

In this 4th annual HART

supplement, we present ideas,

information and testimonials on

using the POWER of HART

HART0409_07_EDIT.qxd 8/24/04 10:28 AM Page S-7

A t BP’s PTA (Purified Terephthalic Acid) plantin Wando, S.C., managers are facing a

dilemma familiar to their counterparts at thousandsof manufacturing facilities throughout the country:do more with less.

“BP is interested in maximizing our competitiveposition. Our objective is to lower costs andincrease our availability. We need to use what wehave and use it better,” says A.J. Lambert, an instru-ment and electrical reliability specialist with BP.

One way plant personnel are achieving that goal isby using a previously underutilized technology thatis providing them with a remarkably detailed view ofconditions throughout their plant and the ability toreduce asset management/maintenance costs.

The “silver bullet” that’s generating these benefits: theHART Field Communication Protocol. “Through theuse of HART diagnostic information, this BP plant issaving a hundreds of thousands of dollars per year inmaintenance and production costs,” says Lambert.

Feel the PowerOf course, not every plant will attain such dramatic

results, but most users can achieve all, or nearly all,of the functionality they seek by tapping into theproven power of the HART-enabled field devicesthey may already own. As a result, most of the bene-fits they achieve through the use of HART commu-nication drops right to the bottom line.

HART’s exceptional value to process manufacturerslies in its ability to simultaneously communicate aninstrument’s primary variable via a standard 4–20 mAanalog signal and additional process variables anddiagnostic information via digital signals on the samewire (See accompanying article). Initially, HART wasembraced by maintenance staffs who were delightedto be able to use handheld communicators and cali-brators, such as those made by Meriam Process Tech-nologies or Emerson Process Management, and takethem into the field. All they had to do was attachthem to any HART-compliant instrument—regardlessof manufacturer–and they were immediately able toretrieve critical information about an instrument’scondition, its health and its range. They could alsoperform and document calibrations and obtain muchmore digital information besides.


Powerofhart

The Power is In Your HandsLooking for a Digital Field Network? With HART, It’s Right in Front of You

HART0409_10_14_LEAD.qxd 8/24/04 10:29 AM Page S-10

Since then, manufacturers have developed a widerange of new intelligent products and added HARTcapabilities to existing ones, providing even greaterbenefits to a broader base of users. For example,field device makers such as Siemens differentiatethemselves by communicating additional HART datathat is unique to the company’s instruments.Siemens pressure transmitters have the ability tomonitor and store data on the highest and lowestpressures experienced by the entire instrument, theinstrument’s pressure capsule and its electronics,says Lou DiNapoli, marketing manager for the com-pany’s pressure and temperature transmitters.

“All users have to do,” says DiNapoli, “is use aHART handheld device or our Device DescriptionLanguage (DDL)-enabled Simatic Process Device Man-ager (PDM) software to get that information, which ishighly useful in diagnosing process problems. If youuse someone else’s equipment and software, you needthe Device Description for our instrument.”

Sophisticated Asset ManagementIn recent years vendors have developed sophisti-cated asset management software packages, includ-ing Yokogawa’s Plant Resource Manager (PRM),Siemens’ PDM, Emerson Process Management’s AMSand Honeywell’s Asset Manager PKS, that enablemaintenance engineers to view,track and analyze the condition ofinstruments remotely. In theseapplications, data from a devicemay be split into separate analogand digital signals. The analog sig-nal, carrying the primary variable,is routed to the control system,while the digital secondary valuesand diagnostic data are conveyedto the asset management systems.

Asset management systems and their ability to useHART data are proving enormously beneficial asnumerous users will attest.

BP’s Wando plant started tapping the full poten-tial of HART about five years ago, when it installedEmerson Process Management’s ValveLink softwareto gain diagnostic information from its approxi-mately 125 most critical control valves.

“Before using HART, we would pull out 35-50valves for maintenance during shutdowns every twoyears,” says Lambert. “There might have been a workorder or some concern about a particular valve, butwe really didn’t know what might be wrong with it.As a result, we’d spend a lot of money and time.Now, with more information from ValveLink and

HART, we pull only five or six valves during a shut-down. And we have a lot more information aboutwhy we’re pulling it. Our diagnostic system canshow us when a problem assumed to be in a valvereally isn’t, but is perhaps somewhere else in theprocess. In other cases, we’re able to see potentialproblems in valves before they become serious.”

Petro-Canada, which is implementing projects atits Montreal and Edmonton refineries to reduce sul-fur in its gasoline and diesel fuels, will use HARTdata for troubleshooting valves and field instruments,says Pat Castelino, PE, a managing engineer with thecompany’s process technology and reliability group.

“I expect a manpower reduction in the startupphase of the project and then on a lifecycle basis,”says Castelino, when asked about potential benefitsstemming from the use of HART data. “We feel thatthe additional information we incorporate into ourasset management solutions will help us establishmore effective predictive maintenance practices.”

Several factors make HART solutions relatively easyand cost-effective to implement. First, HART does notrequire a costly “rip and replace” strategy. The HARTprotocol runs on standard wiring that most plantsalready have in place and, as mentioned, there aremore than 14 million HART-enabled devices alreadyin use. Often, field instruments that are not HART-

ready can be easily and inexpensively upgraded. Because HART represents an enhancement of the

standard 4–20 mA analog field communicationsstandard, there is no need for companies to under-take major retraining programs. Courses offered byHCF, vendors and other sources generally provideall the background information plant personnelneed to use HART effectively.

In addition, the HART network architecture issimpler than that of most all-digital fieldbus proto-cols, making it the ideal option for many plants.

“If I’m putting in a 4–20 mA system with HART, theengineering is very simplified; it’s basically a matter ofrouting wires from the control system to the final ele-ments,” says a major refiner’s senior engineer.


Asset management systems

and their ability to use

HART data are proving

enormously beneficial


Easy and EffectiveIn addition to HART being relatively easy and cost-effective to implement, plants can adopt it verygradually and realize benefits, even on a small scale.For example, many users get their first experiencewith HART by commissioning instruments on the“bench” in maintenance shops. All that’s required isa PC equipped with DDL-enabled asset managementsoftware and an interface between the computer andthe field device–typically a HART modem.

Thomas Holmes, president of HART modemmanufacturer MACTek Corporation, says there are significant advantages to using a desktop ornotebook computer for bench or field configura-tion of HART-enabled devices rather than usinghandheld configurators.

“All of the information you need about all of thedevices you use is right there on your computer’shard drive. You can do signal processing, a host ofhigher-level diagnostic applications data storage,

and/or downloading of archived configurations thatare right on the computer. You don’t have to gothrough the trouble of downloading a device config-uration from a server, loading it into the handheldconfigurator and then reversing the process whenyou get out to the instrument,” he says.

Besides producing modems for RS-232 serialports, MACTek recently began producing modelsthat use USB ports. In addition to USB ports beingsimpler to use, many computer vendors no longerinclude serial ports on their computers, making theUSB version a necessity. Also, multiple devices canbe attached to a single USB port through the use ofUSB hubs. As a result, says Holmes, some customershave been able to set up small monitoring/dataacquisition systems using several USB modems.

“There’s one customer doing a fiscal meteringapplication involving custody transfers of product. Heneeds high accuracy and reasonable sampling rates,”says Holmes. “The application requires him to moni-


Powerofhart

In 1993, the HART Communication Foundation(HCF) was established to provide worldwide

support for application of the HighwayAddressable Remote Transducer technology—orHART Field Communications Protocol. The HCFowns the HART technology, manages theprotocol standards, and ensures that thetechnology is openly available for the benefit ofthe industry. The ARC Advisory Group, Dedham,Mass., estimates that, of the approximately 40million field devices installed worldwide, 26% areHART-enabled, making it the most widely usedprotocol for smart field instrumentation.

HART is a hybrid communications technologyin which a modulated, two-way digital signal isimposed on the industry-standard 4–20 mAanalog signal carrying the primary processvariable. The digital signal conveys additionalprocess variables, device status and diagnosticsinformation that can be routed to assetmanagement, process control and safetysystems. This means that HART provides twosimultaneous communication channels on thesame wire–the industry standard 4–20 mAchannel for fast, reliable and robust control (PV)and a digital channel for real-time communi-cation of additional process/device information.

HART includes a standardized application layer

addressing device status and diagnostics, cyclicalprocess data including floating-point digital value;engineering units, data quality and status. Theprotocol also enables field devices to continuouslypublish their process data and standardizedoperating procedures (e.g., loop test, current loopre-ranging and transducer calibration).

Every HART device includes 35–40 standardpieces of information, which are easilyaccessible by all HART-enabled systems. Theseinclude device identification, basic calibrationdata, process variables (measured andcalculated) and diagnostic alerts. All HART-smartfield devices continuously assess and monitortheir own performance and return diagnosticstatus information with every message.

A HART innovation was the creation of DeviceDescription Language (DDL)–an object-oriented,text-based language for modeling the character-istics and real-time capabilities of intelligent fielddevices. Instrumentation suppliers use DDL tocreate a Device Description (DD) file, which issimilar to an electronic data sheet describing allcapabilities of the smart field device so that theDD-enabled host systems can communicate withall device features. In early 2004, theInternational Electrotechnical Commission (IEC)approved DDL as an international standard.

What is HART?


tor eight HART loops. They are using eight USBmodems, connected to two four-port hubs, which, inturn are plugged into two PC USB ports. They’reusing Emerson Process Management AMS DeviceManager to monitor the equipment.”

Moore Industries’ HART Interface Monitor (HIM)is another product particularly well-suited to small

and medium-sized installations or those that lackan asset management system, says John Emmett,Moore’s London-based HART specialist.

The Moore Industries HIM passes the 4–20 mA sig-nal directly into a DCS or a PLC, but it also breaks outthe digital signals, converts them to analog and makesthem available to the control system as well for alarm-ing and other functions.

Using the two alarm relay contacts in each HIM,users can set limits around process variables.

“For example, with a smart valve positioner, youhave the control system using a 4–20 mA signal todrive the valve open and closed. Using an HIM, youcan read the valve position feedback over the samepair of wires and return it to the control system. Inaddition to there being a cable savings, the alarmrelay contacts act as ‘soft’ limit switches. So you canset a trip limit within the HIM and cause a relay toclose when the valve reaches its limit,” says Emmett.

The digital feedback on the valve position also canbe used in safety system applications, a burgeoningapplication for HART technology (see sidebar).

Other components that enable users to implementand expand their HART-based field networks aresmart distributed I/O modules, such as those pro-vided by Rockwell Automation.

“Instead of running all of the wiring back to thecontrol room from each individual device, our FLEXI/O is out near the field and brings the data back via anetwork. This reduces long home-run wiring runsfrom multiple field devices, and it reduces the number

of terminations you have to do per point for fielddevices,” says Pat Moyer, Rockwell Automation’s mar-keting manager for distributed I/O.

Like a multiplexer, smart, distributed I/O sepa-rates the analog and digital signals and routes themto the appropriate systems.

Multiplexers, including those manufactured byMTL Instruments, enable users to sim-plify their wiring and scale up their sys-tems incrementally. For example, byusing MTL’s MTL4840 HART connec-tion system, users can connect nearly8,000 loops to a single PC communica-tions port and easily configure a scan listand get LED indications of the loopbeing scanned, says Tess Thonger, aMTL marketing manager.

Because HART delivers many of thesame benefits as all-digital fieldbus pro-tocols, it’s not surprising that there’sconfusion in some potential users’minds about the technology. Part of the

problem stems from users’ mindset based on theirinitial exposure to HART, says Jim Cobb, EmersonProcess Management’s Plantweb marketing manager.

“It’s a little bit of a case of HART having beenaround long enough that people think they know it,but in reality, they only know the surface,” saysCobb. “Now, when you see some of the systems thatare coming out today, they have pretty good HARTsupport. As the systems vendors start educatingtheir customers, that’s going to be the most impor-tant way the message gets out to the users.”

Joe Serafin, Honeywell’s product manager for HARTintegration, says Honeywell tells its customers thattheir choice of field communication protocols shouldbe dependent on what they want to achieve. “If they’reinterested in peer-to-peer control on the wire, we tellthem to go with Foundation fieldbus. But if they don’twant to do that, they can probably get everything elsethey want out of HART,” says Serafin.

In for the Long HaulFew industry observers question that, in the longrun, the process industries will eventually migrate tofieldbus protocols. But don’t even think aboutmothballing your HART devices anytime soon.

HART combines the reliability and robustness oftoday’s analog signal with the power of tomor-row’s digital field network. Considering the mil-lions of HART devices already installed, the mostresponsible action for the industry is using HARTto its full potential.


Powerofhart

The digital feedback on

the valve position also

can be used in safety

system applications,

a burgeoning application

for HART technology

HART0409_10_14_LEAD.qxd 8/24/04 1:34 PM Page S-14

New Value from Your HART-Enabled AssetsHART in the Control System Lets Users Realize Great Gain Without the Pain

While HART provides users with enormousvalue through the exchange of digital data

via asset management and maintenance systems, thevalue of that data would leap if users could integrateit into their real-time control systems. Fortunately,that’s now possible.

Major control vendors who offered HART as well astheir own proprietary digital field protocols (e.g.,Yokogawa’s BRAIN, Honeywell’s DE, Foxboro’s Fox-Com, etc.) have yielded to user demand and enthusi-astically embraced HART. Today, virtually every majorautomation system vendor includes native HART I/Oin their control systems, meaning users can now inte-grate secondary variables into their control schemes,ensure that their analog 4–20mA signals represent theactual situation in the field, and troubleshoot prob-lems quickly to minimize process disruptions.

“A control system can be considered to have fullHART capability if it supports true, full-time com-munication with both the digital and 4–20mA analogsignals of HART-enabled field devices,” says WallyPratt, chief engineer of the HART CommunicationFoundation. Other important factors are smartHART-enabled I/O with HART capability at everychannel (as opposed to being multiplexed or sharedacross several channels); controllers that are HART-aware, enabling them to use HART data; and theability to display HART data on operator stations.

New Valuable CapabilitiesUsers who implement HART-enabled control sys-tems gain new, valuable capabilities. Among themost important is the ability to validate their pro-cess data. As reliable and time-proven as 4–20 mAsignals are, external electrical noise, faulty instru-ments and other problematic inputs can produceerrors that are not immediately apparent.

“In control systems with HART I/O, the 4–20mAsignal can be validated continuously,” says Pratt.“The I/O continuously checks the loop current foragreement with digital values being sent by the

device. If there is a disagreement, the problemshows up immediately on the operator interface.

“Information where you continuously monitorvalve position versus the desired setpoint that you’resending can represent a major cost savings, becauseif the valve is not tracking the setpoint, then yourcontrol strategy is in jeopardy. There’s no way to doadvanced control if you don’t know if the valve isgoing to the position you want,” Pratt adds.

HART capabilities in control systems also enableusers to quickly detect field device problems. If a


HartINControl

With HART-enabled field devices, operators can detect andcorrect costly process overload and other dangerous conditions.

Sour

ce: E

mer

son

Proc

ess

Man

agem

ent

HART0409_17_19_INCON.qxd 8/24/04 10:31 AM Page S-17


HartINControl

system is able to display an instrument’s self-diag-nostics data as well as changes in device status, pro-cess disruptions can be avoided, since operators canspot and react to the problem quickly.

The availability of multivariable device data alsoenables operators to anticipate situations they mightnot be aware of otherwise.

According to Pratt, “Most HART-enabled pressuretransmitters also have ‘temperature’ as a secondaryvariable. Wouldn’t it be nice to be able to have theinstrument tell the control system when the instru-ment temperature is about to drop below freezing,so a heater can be turned on, either manually orautomatically? All you need is the ability to read thatsecondary variable. You can save downtime andpossibly avoid damage to your equipment.”

Detect, Correct, ProtectIn addition, HART data enables operators to detectand correct process overload conditions. If a loopcurrent becomes saturated, readings go “off the scale,”and the operator essentially is blind to the situation inthe field. Often, the problem stems from the processmeasurement being out of range, but determining thesource of the problem typically requires dispatchingan instrument specialist to the field. However, if thecontrol system is receiving the instrument’s digitaldata, the operator is able to see the actual values theinstrument is generating. Standardized device statusalerts also assist the diagnosis by indicating whetherthe process condition is outside the sensor limit orjust outside the 4–20mA range. The net result is areduced need for emergency manpower and the pos-

The HART protocol’s bi-directional, digitalcommunication capability has given the

technology a vital role in the testing of safetyinstrumented systems that protect people, theplants they work in and the environment.

By their very nature, valves in a safety systemremain stationary nearly all the time, but in thoserare instances when they’re called upon to bringabout the safe shutdown of a process, they mustwork without fail. The only way to ensure that asafety system valve will function when it’sneeded is to periodically test it. In fact, thelength of time between tests has a major effecton the system’s Probability of Failure on Demand(PFD), a factor in determining the SystemIntegrity Level (SIL) under industry regulationsgoverning safety systems. Lengthening theinterval between tests has a linear affect on thePFD. So, if the length of time between tests isdoubled, the PFD is doubled as well.

“Therefore, it is imperative that these valvesbe tested frequently in order to reduce the PFDand meet the target SIL rating,” says Riyaz Ali,development manager for Emerson ProcessManagement’s FIELDVUE instruments.

The answer: partial stroke testing. Stroking asafety valve as little as 10% does not have asignificant effect on the ongoing process, but itprovides enough travel to determine the valve’sresponsiveness in emergency conditions.

What’s necessary in this situation is feedbackfrom a positioner to verify that the valve actually

has moved, as expected. Consequently, somevendors are providing that capability via HART.

“The HART protocol defines a device-statusbyte, which is determined by the HARTstandard,” explains John Emmett of MooreIndustries International. “It says things like‘ asignal has gone over-range’ or ‘a signal haslocked up.’ There are eight defined states inHART protocol, one of which is called‘additional status available.’ That’s the one thatallows manufacturers to build in their ownspecial features, like partial stroke testing,”notes Emmett.

“Our HART Interface Module can pick upsignals like ‘test in progress,’ so we can actuallyindicate back to the control system that a partialstroke test is happening. But more importantly,the smart positioner can detect if the valve isstuck. We can pick up that particular alert andalarm back to the control room,” adds Emmett.

Emerson Process Management notes that usersof the Fisher DVC6000 Series of digital valvecontrollers and Emerson’s AMS ValveLinksoftware for emergency shutdown solutions do notrequire the presence of personnel in the fieldbecause the controller’s software is able to toprovide feedback on positioner information viaHART. In addition, they can automatically initiatepartial stroke testing routines.

Many plants using this technique haveextended their intervals between scheduledshutdowns–results that appear on the bottom line!

HART’s Critical Role in Safety System Testing


sible avoidance of unnecessary downtime.The availability in a HART-enabled control system

of multiple variables from a single instrument givesusers the ability to put that data to work in theircontrol schemes.

“For example, one of our customers is thinkingabout doing his own level of condition-based mainte-nance by taking additional information provided bythe valve—such as the number of strokes or closedtimes–and integrating it into the process logic,” saysDave Smith, manager, Plant Network Technologies,Yokogawa Corp. of America.

The decision process willindicate that, if a valve hasreached a level of operation asmeasured by the number ofstrokes, the packing is worn andthe process should switch to adifferent valve, perhaps auto-matically, says Smith.

“This is a big improvementover previous ways of doingthings, which involved lookingat the process variable anddeciding whether it was good or bad,” he adds.

Inherent Architectural SimplicityAnother advantage to routing HART signals to acontrol system rather than a separate entity, such asan asset management system, is its architectural sim-plicity. “There’s a lot less hardware, which means alot less risk,” explains Smith. “The capital expendi-ture is lower, and you don’t need multiple PCs,multiplexers and other components.”

Pratt cautions, however, that not all HART-

enabled control systems are created equal. Whilesome provide one-to-one I/O, others rely on multi-plexed data, which creates latency. While this doesnot matter a great deal in some applications (inwhich variables do not change frequently) in otherapplications such latency is unacceptable.

Even with multiplexed systems, however, userscan install products, such as Moore Industries’ HARTInterface Module, on critical loops and place them in“burst mode.” In burst mode, a field device continu-ously publishes data to the module. “It’s a faster way

of getting information, but in addition, burst modedoesn’t require the host to poll the devices, so there’sless overhead on the control system,” says Pratt.

No matter which control system users pick, or themeans that the system uses to incorporate HARTdata, they are positioning themselves to use a signif-icant source of data at the heart of the process thatmight otherwise go untapped. With this additionalinformation in hand, operators and engineers havethe ability to lower operating costs and increaseplant availability.


Another advantage to routing

HART signals to a control

system rather than a

separate entity is its

architectural simplicity

With HART, processors can increase plant availability and lower operating costs.


If it’s apparent to you that HART’s potential bene-fits go way beyond taking readings with hand-

held configurators in the field, you may be thinkingabout taking some careful steps toward tapping yourHART-enabled field instruments for value. But likemost journeys, the first steps are the most intimidat-ing. Where to begin? What to expect?

Look Before You LeapFortunately, you can implement HART a little at atime, so look for projects with the most potentialvalue, start small, expand gradually, and be willingto take a few prudent risks.

Become the HART championin your organization–Usersinvolved in all aspects of plantoperations have a role to play inimplementing HART and attain-ing its benefits, and in mostcompanies, no single group“owns” HART. Consequently,you have an opportunity to be aHART champion in your organi-zation. If there are areas inwhich you think HART can be advantageous to yourbusiness, why not step up and drive the effort?

Select a proving ground–The fact that even thesmallest HART implementation can yield benefitswith minimal investment can relieve some of therisk and anxiety that naturally accompany upgradeprojects. Pat Castelino of Petro-Canada recommendsthat users start small and carefully evaluate areasripe for HART-driven improvements:

”People should start off small and find very spe-cific projects that they feel comfortable with. Andthen, they should actually go through the learningprocess, deciding and quantifying benefits at variousstages,” he says. Several other users and vendors hadmore specific recommendations along those lines.

“A plant can begin by using a single multiplexerand a stand-alone asset management system to mon-

itor up to 32 of the plants most important loops,”says a senior engineer with a major oil refiner. “Thatway, you can start to realize that you can monitorthe health of your instrumentation and start movingfrom fighting fires and suffering capacity loss tobeing able to detect instrument health issues beforethey have an impact on your business. Once you’veproven the value to yourself and your management,expand to other critical areas of the facility.”

Carefully evaluate your expenditures–As men-tioned earlier, nearly every plant has at least some ofthe components it needs to begin realizing HART-enabled benefits. Before investing in additional hard-

ware and software, evaluate what you already have anddetermine how much more you actually need to invest.

“You need a good asset database, so you can fig-ure out what the critical points are in your plant,because they’re the only ones that really need smartinstrumentation,” says Louis Reeves, who is incharge of control valve asset management at Interna-tional Paper in Pensacola, Fla.

“It’s a big waste to spend a lot of money on mar-velous technology where you don’t really need it,”Reeves adds. “It’s like getting an 800-horsepowerengine for your Ford Mustang. Where are you goingto drive it, and are you really going to use all of thathorsepower? I don’t think so.”

Joe Serafin, Honeywell’s product manager for HARTintegration, says his company has a series of questionsusers can ask their instrument vendors to determine


HartStart

If there are areas in which you

think HART can be advantageous

to your business, why not step

up and drive the effort?

Ready for HART? Pick a High Value Project to StartWhen Implementing HART, Experts Advise Start Small, But Think Big

HART0409_21_22_START.qxd 8/24/04 10:33 AM Page S-21

how much information is available from their devices.”Which version of the Universal Commands (HART

5 or HART 6) does the device use? What secondaryprocess variables are available from the device? Doesthe device support HART Command 48 for device-specific status? Are all available device informationand features defined in the Device Description? Theseare the kinds of questions users need to ask in order

to determine, with all HART’s potential, if the vendor’sput it into his product,” says Serafin.

Think in terms of benefits, not just technologicalcapability–“If they say HART is the answer, then myquestion is ‘How do you want to use the data?’ ” saysSteve Lazzok, a support specialist with YokogawaCorp. of America. “If they don’t know, it means to methat they may be wasting their money until they havea clearer plan in mind. If you’re going to bring in thedata, how are you going to make or save money fromit? How are you going to implement preventive main-tenance? How are you going to reduce accidentalshutdowns? The user should consider these questionsbefore making investments.”

Conversely, however, you should not be afraid toinvest in HART technology on at least a small scale,even though the immediate payoff might not beapparent, says Dave Smith, manager, Plant NetworkTechnologies, Yokogawa Corp. of America.

“I know that ‘technology for technology’s sake’ is adifficult issue in our business, but could you have imag-ined 15 years ago that you’d need an Internet browserto do your job? Sometimes technology gets you some-place that you wouldn’t have dreamed,” Smith adds.

Users have indicated that getting the projectapproved is easier when you can show the ability toimplement HART Communication without having

to shut down processes.Question vendors thoroughly–While on a super-

ficial level, it might seem like every vendor offers asimilar level of support for HART in their systems,in fact capabilities vary widely. Consequently, HARTCommunication Foundation chief engineer WallyPratt recommends that you carefully question ven-dor companies about their products “HART-ability.”

For example, if you’re evaluating Smart I/O,topics for discussion with your vendorshould include: How much HART capability is built into

the I/O? Can the I/O validate and secure the 4–20

mA signal? What is the ratio of HART modems to

I/O channels? How often does it updateHART data to/from a device.

How well does the system support accessto multivariable device information?

Can you merely “push a button” on theI/O to calibrate the loop current and/orcheck the range?

Does the I/O support multi-drop? Does the I/O automatically scan and monitor the

HART–enabled field devices or is the scanning onlypossible using “pass through.”

Does the system make it easy to use all HARTcapabilities? “Some vendors say, ‘Yes, we can usethe HART data,’ but it might take a little moretraining in one system vs. another to configurethe thing. You want it to be easy,” cautions Pratt.

Does it understand HART Status? Can the system detect configuration changes?

“Ask questions about notification by exception.How does the system detect changes in configu-ration or status? “How do you go about perform-ing tests when there’s an error in the device?”Pratt asks.

How open is the system to third party software?Train your staff in HART capabilities–Experi-

enced instrument technicians and process engineerswill have little trouble familiarizing themselves withHART’s capabilities and putting them to work, andit’s unlikely they’ll require much–if any–additionaltraining. However, if you want an in-depth look atHART and the way it’s used, you can obtain trainingfrom many of the vendors who sell HART-enableddevices and systems. In addition, the HART Com-munication Foundation offers numerous coursesglobally, educational webcasts and a CD-basedlibrary of information. Need more help? Visit theHCF web site at www.hartcomm.org.


HartStart

Even small HART implementations can yield plant-wide benefits.

HART0409_21_22_START.qxd 8/24/04 10:33 AM Page S-22

Get Connected

ver the past three years, automation suppliershave introduced new control system interfaces,remote I/O systems, and software applications to

leverage the intelligence in HART-smart field devices forcontinuous real-time diagnostics and process information.Real-time connections are the key to unlocking the riches ofyour installed HART devices and to helping you lower main-tenance costs, increase plant availability, improve plant oper-ations, and facilitate regulatory compliance.

In this issue, we present ideas, information, and examplesof putting the power of HART to work—maximizing and opti-mizing assets. Our 2003 HART Plant of the Year winner is a great example of unlocking the value in HART-enableddevices. The Detroit Water & Sewerage Department discov-ered the powerful capabilities of their HART devices—alreadyinstalled—and combined them with other technologies to cre-ate a solution that satisfied their customers, their management,and their technicians. We thank those of you who submittedyour plant applications for consideration as the 2003 HARTPlant of the Year. Don’t miss this article because it shattersthe image you might have of water system applications.

Asset management is the hot topic these days and with thetight budgets I’m hearing about, you can’t afford to overlookthe untapped value of HART-enabled devices. HART commu-nication is a key enabler for asset management—so get con-nected and realize the potential of your installed HART devices!

Regardless of your control system, the 150-plus membersof the HART Communication Foundation (HCF) have cost-effective solutions to help you. This year, the HCF is celebrat-ing its 10th anniversary, and HART technology remains theprotocol of choice for communication with intelligent processinstrumentation around the globe. With our continued enhance-ments to the technology—including our focus on DeviceDescription Language and new development tools—HARTwill remain the simple, low-cost, low-risk, and high-value process communication solution for your plant operations.

Want to learn more? Call us—we’ll be happy to help you get connected and realize the potential of your HART applications! ◊

Ron Helson, Director HART Communication Foundation512/[email protected]

Advertiser Circle No. Page No.

Emerson Process Management/PlantWeb 100 S-21

Endress+Hauser 101 S-8

The Foxboro Co. 102 S-25

Harold Beck & Sons 103 S-22

HART Communication Foundation 104 S-28

Honeywell Industry Solutions 105 S-16, S-17

MACTek Corp. 106 S-11

Moore Industries 107 S-4

Ohmart/Vega 108 S-18

Siemens 110 S-2, S-3

Smar 109 S-27

Yokogawa 111 S-6, S-7

9 Platform for the FutureNew Capabilities Make HART a Fieldbus to Be

Reckoned With. The Protocol’s Evolution Includes

Powerful Real-Time Applications

14 The HART of Asset ManagementHART Capabilities Offer Fundamental Value While

Real-Time Connections Deliver Results

19 Time to Tap Into HARTSeize the Data. There Are Major Asset Management

and Process Improvement Gains to Be Realized

With HART

23 HART Plant of the YearThe Detroit Water and Sewerage Dept. (DWSD)

Uses HART to Eliminate Metering Disputes,

Improve Reliability, and Streamline Operations

Ad Index

Contents OO

HART® is a registered trademark of the HART Communication Foundation.

Adver t i s ing Supplement to CONTROL S-5

HART03_05_INTRO.qxd 9/15/03 1:35 PM Page 5

s part of a major upgrade to aplant in Sao Paulo, Brazil,plate and specialty glass

manufacturer Cebrace sought toimprove the volume and quality ofdata it was receiving from its plantequipment, so it could improve main-tenance quality. Although the plant hasa Foundation fieldbus network inplace, the plant elected to rely oninstrumentation using the HART pro-tocol for the data it needed.

According to Benedito Adalberto Pes-tana, a Cebrace engineer who worked onthe instrumentation project, plant tech-nicians were more familiar with HART

and felt comfortable relying on itsproven capabilities in critical situations.Using a HART-to-Foundation fieldbusgateway developed by Smar, Cebraceoperators were able to view and controlinstruments on both networks from thesame Smar AssetView interface.

“The benefit for us was the ability topull all of our process informationtogether, improve maintenance quality,and, most important, improve our meantime between failure,” says Pestana.

Feature-RichWhile most industrial users associateHART with handheld terminals and in-

the-field-configuration of instruments,Cebrace and other companies are rec-ognizing that this proven, reliable com-munications technology is capable ofdelivering much more value. HART—introduced more than a decade ago—is finally being recognized as a feature-rich, highly capable communicationstechnology that permits full-time com-munication among field devices andcontrol systems. Among the benefitsHART delivers to users are a reductionin costly unplanned outages throughimproved, real-time troubleshooting;better use of field assets; and a rich,real-time flow of data that enables usersto introduce new, high-value applica-tions for control and asset management.

Meanwhile, HART’s presence inplants all over the world increases everyday. The vast majority of installedsmart instruments are HART-capable,and many of those that aren’t can beeasily and inexpensively upgraded. Inaddition, the protocol is included inmore than two-thirds of all smartdevices now being installed.

Brian Oeder, marketing manager forinstrumentation maker Ohmart/Vega,noted that his company considers HARTcompatibility to be a basic requirementof any instrument in use or being soldtoday. “We don’t consider HART capa-bility to be something special anymore,”says Oeder. “We consider it somethingthat is absolutely necessary for doingbusiness. We wouldn’t think of devel-oping an instrument without HART.”

See the LightStill, despite HART’s universal presencein plants around the world, many usersare unaware of the cost-effective capa-bilities the protocol provides and theenormous returns they can gain with vir-

Adver t i s ing Supp lement to CONTROL S-9

New Capabilities Make HART a Fieldbus to Be Reckoned With. The Protocol’s Evolution Includes Powerful Real-Time Applications

Platform for the Future

AA

HART has been in wide use for more than 10 years, but the protocol con-tinues to evolve and grow in value to users around the world.

The HCF last year finalized HART 6, the latest version of the protocol.HART 6 enhancements provide additional diagnostics and many new capa-bilities to improve integration with plant control and safety systems—allwhile protecting users’ investments through backward/forward compatibil-ity with existing networks and devices. Consequently, HART 6 systems cancommunicate with HART 5 instruments and HART 5 systems can commu-nicate with HART 6 instruments. However, access to the full range of HART 6 functions requires both masters and slaves to be HART 6-enabled.

New features and capabilities support multivariable and valve/actuatordevices, enhance status and diagnostics, increase interoperability, andextend commissioning and troubleshooting capabilities. Among the manynew features in HART 6:• Device Variable Classification: Allows control systems and other

master applications to determine the number and type of process-related variables available within a device.

• Extended Device Status: Provides an additional byte for device statusalerts, such as "Device Needs Maintenance."

• Device Variable Status: Allows field devices to assess and report on thequality of the data being transmitted.

• Catch Device Variable: Enables devices to share process data via peer-to-peer communication for use in complex flow calculations or functions.

• Block Data Transfer: Supports the transfer of large blocks of data amongmaster applications and field devices.

HART Technology Enhancements Increase Value to Users

HART03_09_13_FUTURE.qxd 9/8/03 5:39 PM Page S-9

tually no additional device investment. “When a user finally sees the light

about the power of the extra informa-tion in HART, they discover that thebulk of the investment is already sittingin their plant,” says Hoag Ostling, chiefapplication engineer with Yokogawa.“All they have to do is tap into it.”

The evolution of the HART protocolis being driven by several key factors.First is the ubiquity of HART in fielddevices — it’s everywhere. In addition,virtually all major vendors of controlsystems include the native ability tocommunicate digitally via HART on acontinuous, real-time basis, meaningusers have the ability to tap the fullrange of data in their field devices andincorporate that information directly

into their control schemes.For those unfamiliar with HART, or

in need of a refresher, a quick review isin order. HART is a digital field com-munication protocol that enables intelli-gent field devices to communicate withcontrol systems, asset management sys-tems, safety systems, and other mainte-nance and configuration tools. WhileHART uses the familiar 4-20 mA ana-log standard, it piggybacks a digital sig-nal atop the analog that conveys a wealthof information, including secondarymeasurements and data useful in deviceand process diagnostics and monitoring.

HART’s evolution from a mainte-nance and configuration tool to a highlycapable digital network for control aswell as asset management began when

the protocol first became available tovendors and users in the early 1990s.

Technicians in the field generallyattached a handheld communicator toeach instrument to obtain additionalHART-enabled data, calibrate, and con-figure the device. This provides hugebenefits, but in large installations suchas refineries, months typically passbefore the device’s communicationcapability gets used again.

Later, users gained better access toHART data through multiplexers,HART modems, and other devices thatenable them to access the digital devicedata remotely and store it in PC-basedapplications for asset management. Typ-ically, these systems would poll eachinstrument just once or twice per day inlarge installations—an improvementover monthly onsite visits, but still a farcry from an up-to-the-second picture ofan instrument’s condition.

New View From the Control SystemWith the inclusion of HART in controlsystems, however, users suddenly hada powerful new real-time technologyto improve plant floor visibility, trou-bleshooting, and control.

“We have a software tool that allowsyou to have a connection to all yourHART devices at all times so you canview status and make changes online,without any interruption to the process,”says Andreas Aufenanger, U.S. productmanager, Siemens. “Whatever changesyou make to a device are instantlyrecorded in the same central database.”

Invensys’ Foxboro automation sys-tems contain HART input cards witheight channels, each with its ownmodem circuit. These features makefull-time communication with intelli-gent field devices fast and easy.

“We’re able to speak to eight trans-mitters at once, so we’re getting statusand diagnostic information every sec-ond, rather than monthly or daily,”

“We don’t consider HART capability to be something special anymore. We consider it absolutely necessary for doing business.”

S-10 Adver t i s ing Supp lement to CONTROL

Earlier this year, the HART Communication Foundation (HCF) entered intoa collaborative agreement with the Fieldbus Foundation (FF) and ProfibusNutzerorganization e.V. (PNO) to enhance the Device Description Lan-guage (DDL) supported by all three organizations.

The jointly developed enhancements will provide additional DDL con-structs and functions to support the data visualization needs of sophisti-cated devices for full-screen graphical displays and data captures forperformance assessment. The DDL enhancements will allow device manu-facturers to describe display layouts and persistent data storage needsentirely within the device DD file—including graphical display elementssuch as photos, two-dimensional plots/charts, and data groupings by win-dow, dialog, tabbed-dialog, table, and/or menu.

DDL is an object-oriented, text-based language for modeling the char-acteristics and real-time capabilities of intelligent field devices. Instrumen-tation suppliers use DDL to create Device Description (DD) files describingthe capabilities of their smart field device products. Procedures for properoperation and read/write access to device parameters are described in thedevice DD file. DD-enabled host applications such as handheld communi-cators, calibrators, control systems, and asset management systems usethe DD file to display device information and interact with the device forcalibration, commissioning, diagnostics, and maintenance functions.

HART was the first protocol to implement DDL. For more than a decade,it has proven its value as a stable platform for suppliers to define and doc-ument the capabilities of HART-capable products in a single, open, andconsistent format. DDL is the standard of HCF, but soon it will become aninternational standard of the International Electrotechnical Commission(IEC) known as IEC 61804-2, EDDL.

HCF, Profibus and FF Enhancing Device Description Language


says Charles Piper, Foxboro’s fieldbusproducts manager.

Yokogawa offers fully redundantHART interface modules for its CEN-TUM CS 3000 R3 distributed control

system as part of the company’s Field-network I/O subsystem, notes BruceJensen, Yokogawa’s manager of sys-tems marketing and sales support.“These modules can be installed inremotely mounted units within ClassI, Div. 2 environments and includesuch options as ISA G3 corrosionresistance and a high temperature rat-ing of -20-70° C,” he adds.

In addition, Yokogawa’s PlantResource Manager—its field assetmanagement solution—automates datacollection from HART devices. Thesoftware functions as a standaloneapplication or through the CENTUMsystem, and allows integration, man-agement, and maintenance of thesefield devices using a common database.

Ram Ramachandran, director of sys-tems marketing for Emerson ProcessManagement, touts the tight integrationof HART into his company’s DeltaVcontrol system. “In instrument config-

uration, just like everyone else, wehave an explorer view of the whole sys-tem that typically shows the network,DeltaV controllers, workstations, andI/O cards,” says Ramachandran. “But

what we do, that I think is unique, isshow the HART devices in this hierar-chy. That does lots of things for you.You can go into your system, click onan I/O card and ask it to auto-sense allof the devices for you and populate theexplorer with them.”

Systems from companies such asSiemens, Honeywell, ABB, and othersalso offer their own sets of featuresthat enhance HART’s capabilities.

By using a control system withnative HART support or third-partyadd-ons from companies such asMACTek, Moore Industries, MTL,and others, end users can put this datato work in their plants at minimal cost,since many, if not all, of their existingfield devices are HART-compatible. Inaddition, HART operates over thesame wiring as 4-20 mA signaling, andlittle additional training is needed tobring plant personnel up to speed.

Benefits AboundHere are some of the benefits thatHART users can realize today:

Reduce plant downtime, improveasset productivity: “What every cus-tomer wants out of a fieldbus likeHART, first and foremost, is the abil-ity to get faster notification of deviceproblems, so he can avoid either a shut-down or off-quality production,” saysFoxboro’s Piper. By integrating HARTself-diagnostic information in controlschemes or by polling instrumentationthrough a separate asset managementsystem, users can spot potential prob-lems before they happen.

Harold Beck & Co., a Newtown, Pa.,manufacturer of actuators used in indus-trial boilers and furnaces, began incorpo-rating HART in its products about twoyears ago. Scott Kemp, Beck senior pro-cess control engineer, says the diagnos-tic capability embedded in a HARTdevice is a major boon to users who wantto improve management of their plantassets and ensure their maximum produc-tivity. “The diagnostics in HART can tellyou the reason the drive won’t move for-ward right now is because of this specificproblem,” says Kemp. “Or it will tell youhow many times a drive has been over-torqued or exceeded its temperature rat-ings. These all are features that weren’tavailable in standard analog electronics.”

Gain additional value from existinginstrumentation: Most of the smartinstruments installed throughout theworld are capable of measuring multi-ple variables. Using the HART proto-col, manufacturers can acquire theadditional digital information from theirdevices and incorporate it natively intotheir control schemes or route it to sep-arate systems such as PC-based assetmanagement systems, for monitoringequipment health in real time.

For example, Detroit Water and Sew-erage Dept. (DWSD)—this year’s win-ner of the HART CommunicationFoundation’s Plant of the Year award

“We’re getting status and diagnostic information from eighttransmitters every second, rather than monthly or daily.”


Condition and diagnostic information from HART-capable field instruments canbe captured from control networks by online applications and integrated withenterprise asset management systems.

Leverage Your HART Instrumentation


—recently implemented a HART-basedautomated, system-wide metering anddata monitoring application (see p23).

Improve safety systems: HARTserves as a valuable tool to ensure thatprocess plants operate safely. DuPont’sDeLisle titanium dioxide production plant in Pass Christian, Miss. — HARTCommunication Foundation’s 2002 Plantof the Year — uses the protocol to pro-vide key safety interlock inputs to its Honeywell TDC 3000 DCS and its hard-wired safety shutdown relay system. Thesafety interlock system has a number ofon/off control valves, each equipped witha HART-enabled valve-stem positioner.Each positioner communicates with theDCS via a 4-20 mA signal. Digital HARTdata is superimposed on the 4-20 mA con-nection and is extracted by a MooreIndustries SPA HART loop monitor. TheSPA then sends the actual valve-stemposition data to the DCS via an additional

4-20 mA connection. By comparing thetwo 4-20 mA signals, the DCS ensuresproper positioning of the valve stem. TheHART data also allows DuPont to testthe valve safety interlock operation fromthe control room by placing the appro-priate DCS output in manual mode andadjusting the 4-20 mA signal to open andclose the valve. The SPA returns a 4-20mA signal derived from the device’sHART data to verify the valve position.

Continuous validation of data andinstrument accuracy: “Users want tovalidate that the instrument theybelieve is at the end of a pair of wiresis exactly what they expect,” says JoeSerafin, Honeywell’s product managerfor HART system integration. “That’sdone through HART’s ability to accessthe device ID. In addition, users wantto make sure the configuration on adevice is correct, and they want to dothat without having to walk out to the

device with a handheld.”In addition to validating the presence

of the expected instrument, HARTenables users to spot deviations in rangeand loop current, and identify “in-band”errors that might not otherwise be appar-ent. For example, a Midwest refinerysuffered a $300,000 disruption as theresult of a short circuit causing an erro-neous measurement signal to a criticallevel control loop. The problem wentundetected, because the "in-band" errorto the 4-20 mA signal made it seem asthough the level control was function-ing normally. Had the level transmitterand control system been HART-enabled,the mismatch between the 4-20 mA anddigital signals from the level transmitterwould have been detected in real time(seconds), allowing the disruptive shut-down to be avoided.

More efficient use of operationsand maintenance personnel: The useof HART-enabled control systems anddevices enables plants to optimize theuse of operational and maintenance per-sonnel. First, training existing person-nel on the use of HART is relativelyquick and painless, and migration froman analog system to the analog-digitalHART protocol is relatively simple.

During commissioning, users canview and validate loop and field deviceconfiguration from their operator orengineering workstations. HART’s self-diagnostic capabilities reduce the num-ber of false alarms that otherwise wouldresult in fruitless and sometimes haz-ardous trips to the instrument site. Inaddition, HART-enabled data on equip-ment health enables plants to performmore accurate maintenance and replace-ment, further eliminating trips to the field.

Gilbert Hurtubise, consulting engi-neer on Syncrude’s expansion of itsFort McMurray, Alberta, crude oil pro-duction facility, estimates that use ofHART has enabled the company toreduce systems commissioning laborby as much as 70%. ◊


“Users want to validate that the instrument they believe is atthe end of a pair of wires is exactly what they expect.”

HART can easily operate in an environment that includes other fieldbus commu-nications protocols such as Foundation fieldbus or Profibus. Products such asSmar’s HART-to-Foundation fieldbus gateway, in use at Cebrace’s Sao Pauloplant, are enabling companies to view and operate industrial networks as uni-fied entities, even though they rely on multiple communication technologies.

While HART can exist in harmony with newer digital fieldbus technolo-gies, users should take a close look at HART’s functionality before investingin newer and potentially costly technologies. There’s no doubt that thesenewer, all-digital protocols can bring a wealth of benefits to users, but theycome at a cost. For example, use of these protocols usually involves the pur-chase of new instruments, new wiring, elaborate network configuration, andextensive, potentially costly training for plant personnel. HART technology,which is mature and proven, offers many of the same advantages as the newerprotocols with minimal additional investment.

“I can bring the smart information in, and the same people who took careof that transmitter yesterday can take care of it today,” says Joe Serafin, Hon-eywell. “You can probably train someone to be an expert in HART in fourhours. You can’t do that with other technologies. HART is very easy and sim-ple, yet it gives you the core features of other digital protocols without a lotof the overhead.”

So, the next time you hear the word “HART” don’t just associate it withmaintenance personnel, trips to the field, and handheld communicators.Instead, think: “HART: Easy, proven, high value, low risk, outstanding results.”

HART Works With Other Protocols



Field-proven, global industrystandard

Two communication channels simultaneous onthe same wire

4-20 mA analog channel: forfastest possible data transferof control signal

Digital channel: forread/write access to alldevice data

35-40 data items standard inevery HART device

Advanced diagnostics andintelligent multivariabledevices

Many cost-effective solutionsfor integration with plant systems

Unmatched range of productsand worldwide support

Digital data: 35-40 valuable data items standard in everyHART device

Device identification: device tag, supplier, device type and revision, device serial number

Calibration data: upper and lower range values, upper andlower sensor limits, PV damping, last calibration date

Process variables: primary variable plus secondary measurements and multivariable parameters

Status/diagnostic alerts: device malfunction, configuration change, power fail restart, loop current fixed or saturated, primary or secondary variable out of limits, communication error, plus more

Highly accurate and robust communication unlocks value insmart devices

Simple, cost-effective, high-value, low-risk, feature-rich:easy to use and maintain

Lowers cost through faster commissioning and simplifiedmaintenance

Real-time diagnostics and predictive maintenance alertsenable problem detection in seconds

Benefits multiply by real-time integration with plant control,safety, and asset management systems

HART Fundamentals HART Data—Overview

HART Benefits

T

HART Capabilities Provide Fundamental Value

HART03_14_15_CF.qxd 9/15/03 2:01 PM Page S-14


Real-Time Connections Deliver Results

Leverage intelligent device capabilities for operational improvement

Real-time diagnostic alerts provide early warning of device orprocess problems

Reduces time from problem identification to problem resolution

Improve Plant Operations

Increase Plant Availability

Integration with systems enables detection of previously undetectable problems

Early warning enables proactive action to minimize impact

Avoid high cost of unscheduled shutdowns or process disruptions

Lower Maintenance Costs

Quickly verify and validate control loop and device configuration

Remote diagnostics reduce unnecessary field checks

Predictive diagnostics and advanced problem detection capabilities simplify maintenance

Lower spares inventory and device management costs

Aid Compliance

Enable automated recordkeeping of compliance data

Facilitates automatedsafety shutdown testing

Advanced diagnosticsincrease safety integritylevel (SIL)

“HART does the job for us, and you don’t

pay extra for it.”

•••

Dennis Green, Head Engineer

DWSD, Detroit

The HART of Asset Management

Increases asset productivity and system availability

Device and/or process connection problems detected in real time

Intelligent multivariabledevices aid reporting

Continuous validation of control information and loop integrity

HART03_14_15_CF.qxd 9/15/03 2:01 PM Page S-15

s manufacturers wrestle thechallenges of a feeble econ-omy, a slowdown in capital

investment, and intense competition ina global economy, many are searchingfor ways to wring additional value fromtheir existing assets.

Yet in their quest, many of thesesame manufacturers are leaving a majorsource of improvements untapped.Most manufacturers access HART-enabled variables only when mainte-nance personnel go to the field tocalibrate them. And that, say someexperts, is like leaving money on thetable at a card game.

“When you spend money for an assetand then don’t do proper asset manage-ment or let that asset degrade, you’re justnot getting the return you should,” saysJake Oddo, leader of a process controlsteering team for Dupont’s titanium diox-ide business. “In DuPont’s Six Sigmaquality initiative, we view an underuti-lized asset as a defect. With HART, youcan avoid that situation, and you’vealready paid for that HART transmitter.”

Where to Begin?Even users who are aware of theuntapped riches locked in HART-capable instruments might be at a lossabout where to begin taking advantageof this resource. Here are some stepsto consider:

Identify your HART instruments:The first step in many plants – particu-larly large operations that might havethousands of instruments – is to deter-mine which installed instruments areHART-capable. In many cases, this is simply a matter of consulting theplant’s asset management systemand/or instrument documentation. Ageneral rule is that any smart instru-

ment manufactured from the mid-1990s onward almost certainly isHART-capable.

Also, be sure all future instrumenta-tion purchases include the capability tocommunicate via HART. More than150 suppliers offer HART on morethan 600 different devices covering a wide range of measurement and control functions.

Identify benefit opportunities:Determine where you can gain the mostbenefit most quickly by tapping into

the rich flow of data available fromyour HART devices.

“Would you put in a massive pro-gram to acquire information from sumppumps?” says Oddo, whose DuPontfacility in Pass Christian, Miss., was lastyear’s HART Communication Founda-tion Plant of the Year. “Probably not.But would you do it to gain more infor-mation on critical reactor temperatures?Yes, you probably would. In situationswhere you might have temperatureupsets that could cause you to go criti-cal, you could be risking explosions andfatalities, so when you start assessingthose situations, using HART is prettymuch a no-brainer.”

Modest Investments RequiredMost major control vendors have incor-porated HART I/O into their systems,enabling users to integrate digitalHART data directly into their controlschemes and applications. Users of mostlegacy systems do not have this capa-bility, but fortunately, a number of com-panies have developed innovativesolutions to help users get the mostvalue from their instrumentation.

Gil Hurtubise, consulting engineer onSyncrude’s plant expansion project inAlberta, acknowledges users might have to purchase devices for HART con-nectivity and data extraction, special software such as Emerson Process Man-agement’s Asset Management System,PCs to read the data, etc. But he adds,“All of that is offset by a big reductionin labor, because you don’t have somany people running around in the field,verifying calibration. In an applicationsuch as partial valve stroking, you cantell right from your laptop or desktop PCwhether the valve is actually moving ornot. You don’t have to have someone outin the field watching.”

Among the additional investmentsplants might need to consider are:

HART interfaces: An interface suchas the HIM HART Loop Interface andMonitor from Moore Industries stripsdigital HART data from the instrumentfor use in the control system or in appli-cations based on other platforms suchas a PC. For example, smart HARTmultivariable mass flow transmitterssense three process variables (pressure,temperature, and differential pressure orraw flow). Using these data, they per-form an internal calculation to derivemass flow, which is transmitted as a 4-20 mA signal to the control system.

“Unfortunately, unless you have a


Seize the Data. There Are Major Asset Management and Process Improvement Gains to Be Realized With HART

Time to Tap Into HART

AA

Top 10 HART Apps

1. Configuration/commissioning2. Calibration/ranging3. Multivariable device data4. Real-time diagnostics5. Process/device alerts6. Control signal validation7. Safety integrity verification8. Remote SCADA applications9. OPC/Ethernet integration

10. Asset management/optimization

HART03_19_20_START.qxd 9/15/03 2:08 PM Page S-19

HART-based control system, there is no way to continuously monitor the non-primary variables used to make the calculation,” says Steve Todd, MooreIndustries’ marketing director. “By read-ing the HART digital data on the sec-ondary variables and transmitting themas an analog signal, these variables canbe obtained in an older control system.”

HART multiplexers: HART multi-

plexers enable users to save on wiringto field instruments by serving as a fieldinterface to multiple HART-enabledfield devices. Typically, a PC acts as thehost, providing the human-machineinterface and performing other high-level functions. The multiplexer contin-uously monitors the field devices,reports the current readings and instru-ment status to the host, and passes

HART commands from the host com-puter to the field devices. A multiplexeralso can be an integral part of the con-trol system as a third-party I/O. As anI/O system, the multiplexer can includeintrinsically safe barriers and other fil-tering capabilities and provide servicesto the field device, such as galvanic iso-lation or power. For this type of instal-lation, no additional terminations orspace are required.

HART PC modems: Users of desk-top or laptop PCs can equip their com-puters with modems that enabletwo-way communications with HARTinstruments. Among the leading manu-facturers of such devices is MACTek.The devices are available for serial andUSB ports as well as for laptop comput-ers’ PCMCIA card slots. “Our modemswork with just about every HART com-munication software package that Iknow of,” says Tom Holmes, founderand president of MACTek.

While a PC equipped with a HARTmodem can perform many of the sametasks as a handheld communicator—downloading configuration informationto a field instrument, for example—PCsgenerally have far more memory thansuch communicators and are capable ofmore sophisticated tasks.

Protocol converters—Converters candeliver HART data to control systems,asset management systems, and otherplatforms via other digital protocols. Forexample, Smar last year introduced aconverter to deliver HART data via aFoundation fieldbus network. MooreIndustries’ HART Interface Module,mentioned above, also has a HART-to-Modbus option that converts the digitalsignal from a smart HART instrument toa standard Modbus RTU protocol output.

As DuPont’s Jake Oddo puts it:“Right now, your plant might be about10% of the way towards where you wantit. HART may not give you everythingyou want, but it could get you 85 to 90%of the way.” ◊

“HART may not give you everything you want, but it could get you 85 to 90% of the way.”


The HART Communication Foundation (HCF) is an independent, not-for-profit organization that provides worldwide support for the HART technology.Established in 1993, HCF is the technology owner and standards-setting bodyfor the HART protocol. HCF manages the protocol standards, ensures thatthe technology is openly available, and educates users through training andsupport for application of the protocol.

MembershipsHCF memberships are open to any company interested in the use of HARTtechnology—suppliers, systems integrators, end users, and others. HCFmembership provides many benefits including the ability to vote on mattersinfluencing future direction of the protocol, participation on HCF workinggroups/committees, access to HCF technology and tools for HART devel-opment, use of the HART logo, and participation in HCF-sponsored promo-tion activities.

HART Training WorkshopsHCF workshops educate users on HART communication. Workshop sessionsare scheduled quarterly in Austin, Texas, and Basel, Switzerland:• HART Applications: This special on-site workshop provides a basic overview

of HART communication and the capabilities of HART-enabled devices. Thebenefits and options for real-time integration with plant automation/assetmanagement systems also are discussed.

• HART Protocol Fundamentals: The HART protocol is relatively easy to imple-ment, but there is a learning curve. This intensive, three-day, developer-ori-ented workshop provides all the information and tools necessary to efficientlydevelop a HART-based field device or system interface.

• Writing Device Descriptions (DDs): This four-day consultative training ses-sion covers all aspects of the Device Description Language (DDL) and howto use DDL to write the DD for a specific field device. Students leave theworkshop with a working prototype DD for their HART device.

HART Communication Foundation9390 Research Blvd., Suite I-350, Austin, TX 78759

Telephone: 512/794-0369; Fax: 512/794-3904Email: [email protected] Web: www.hartcomm.org

About the HART Communication Foundation

HART03_19_20_START.qxd 9/15/03 2:08 PM Page S-20


he old adage “numbers don’tlie” may be true in some cases,but when buyers and sellers

rely on different sets of figures, the sit-uation is ripe for dispute.

That’s the situation the DetroitWater and Sewerage Dept. (DWSD)decided to rectify in its dealings withsuburban municipality customersacross Southeast Michigan. Manycustomers had measuring devicesoperating in parallel with DWSD’solder equipment. Invariably, the twosystems disagreed and the customeralways argued for the lower-costreading. DWSD was forever in battlesto show the legitimacy of its meterreadings.

In response, DWSD developed andimplemented an extraordinary Auto-matic Meter Reading/Supervisory Con-trol and Data Acquisition (AMR/SCADA) system that relies on thepower of the HART communicationprotocol to deliver consistent, reliabledata on system performance directly tocustomers as well as to the utility.

Citing the utility’s innovativeapproach to real-time use of the HARTprotocol, its aggressive plans to expandits use of HART technology, and theresults it is achieving, the HART Com-munication Foundation selected theDetroit Water and Sewerage Dept. asits HART Plant of the Year for 2003.

Water, Water ManagementEverywhereDWSD’s services extend far beyondDetroit’s city limits to an area of morethan 1,000 square miles includingapproximately 40% of Michigan’s popu-lation. Water flow and pressure are con-trolled and measured through instrumentshoused in nearly 300 underground meter-

ing pits throughout the system. Measure-ment devices include a variety of flowand pressure meters manufactured bySmar, Endress+Hauser, and ABB.

Prior to implementation of theAMR/SCADA project, data wasrecorded via chart recorders and similar paper-producing methods.Because the meters inform the utilityof how much water is being used andby which customers, DWSD’s direc-tor and its head water system engineerrefer to the meters as the utility’s“cash register.”

However, by the mid-1990s, manyof the customers were using cash registers of their own, says Head Engi-neer Dennis Green. The parties dis-agreed over consumption data andthat’s where problems arose.

In response, the department approveddevelopment of the AMR/SCADA sys-

tem (Figure 1), which was successfullypiloted from 1996 to 1997 and is beingexpanded as a $10 million piece of amajor infrastructure upgrade project.

Watershed ObjectivesTo create the system it needed, DWSDand its consultants set five goals:• System dependability: Failure of any

single component could not disruptsystem performance, the flow of data,or the calibration work of the metertechnicians.

• Preservation of metering data: Therecan be no discrepancies between dataanywhere in the system, and theremust be opportunities to recover datawhen failures occurred.

• Standardization of equipment andcontrol of versions of software.

• Minimal reliance on paper documents.• Incorporation of software aids into

The Detroit Water and Sewerage Dept. (DWSD) Uses HART Technology to EliminateMetering Disputes, Improve System Reliability, and Streamline Operations.

HART Plant of the Year

TT

DWSD’s Water Board Building

Office of customer’s water departmenttypical of 85 sites

Community SCADAMaster PC

Oracle database

RADIO

Pumping stations & water treatment plantstypical of 27 sites

DWSD’s Central Services Facility

PC on LAN/WAN

PC on LAN/WAN

SCADAMaster

RADIORADIO

SCADAMaster

RADIO

Distributedcontroller of DCS

Above-ground control cabinet

PLC/RTU

Underground meter vault

PT

DP PT

RADIO

Metering sitetypical of 276 sitesMobile headend for

meter calibration crew

RADIO

Oracledatabase Oracle

database

Oracle database

The new SCADA and automatic meter reading system is being expanded as a$10 million segment of a major infrastructure improvement program.

Figure 1: Extraordinary Meter Reading

HART03_23_26_POTY.qxd 9/8/03 5:40 PM Page S-23

the SCADA system for maintenance,calibration, performance monitoring,and other functions.

At the core of the new system arethe existing flow and pressure trans-mitters and flowmeters. Among theissues DWSD faced were identifica-tion and adoption of a digital meansof measuring and transmitting datathat would work with the variety ofmeasurement technologies alreadyin use (e.g., mechanical meters, venturis, orifice systems, magneticflowmeters, etc.).

The Answer Is HARTDWSD determined that HART pro-vided the best solution for several rea-sons. First, HART minimized theadditional investment DWSD had tomake, since most of the existing instrumentation was HART-capableand could use existing wiring. Inaddition, HART is a stable protocol posing a low compatibility risk for planned expansions. Furthermore,HART enabled DWSD to digitallyextract secondary variables and diag-nostic information, and the intelli-

gence built into HART instrumentsenabled them to perform calculations,freeing computing power in higher-level platforms for other tasks.

For example, the differential pressurecells used in the system are capable ofself-monitoring and on-board totaliza-tion, says Dan Lacy, sales executive for Greenwood, Ind.-based Endress+Hauser. E+H transmitters are usedthroughout the water system to reportpressures in DWSD’s mains and the pres-sures delivered to customers, which canconfirm proper operation of the commu-nity’s pressure-reducing valves and avoid telephone calls to DWSD’s SystemsControl Center.

In addition to approximately 750instruments in nearly 300 metering pitsthroughout DWSD’s service area, the system consists of a PLC/RTUlocated at each meter pit. Each PLC/RTU is connected to the pit’s instrumen-tation and is equipped with radio teleme-try and a battery backup. The two DWSDSCADA head-ends feature dual histori-ans, each capable of maintaining up to 10years of data for recovery and analysis.

Other components of the systeminclude 35 laptop computers that serveas mobile SCADA masters for field cal-ibration and are used to set and down-load instrument parameters. DWSD alsosupplied its customers with approxi-mately 90 PCs that serve as SCADAmonitoring stations, thus giving cus-tomers access to the same data thatDWSD is receiving. All laptop and desk-top PCs run iFIX software and Oraclerelational database management soft-ware and can operate independently ofthe DWSD SCADA headends.

“Every PLC/RTU runs the identicalcopy of software developed for DWSDby Control Microsystems and EDS,”says Cliff Montgomery of RhythmTechnologies, a Michigan consultingfirm that helped design and implementthe network. “We download parametersfrom a laptop PC running GE Fanuc iFIX

“HART is a stable protocol posing a low compatibility risk for planned expansions.”


Through the use of HART, the Detroit Water and Sewerage Dept. integrated a vast array of diverse field devices and technologies on a singlenetworked system that takes full advantage of HART’s digital communica-tion capabilities. The result is a common odometer total display throughoutthe system that can be read via the LCDs on the HART meters just like theodometers of the mechanical meters while the PLC/RTU collects total andinstantaneous rate of flow readings to control switching between the largeand small venturi meters using standard and extended HART commands.

In addition to stemming billing disputes with its customers, theAMR/SCADA system is delivering the following benefits to the utility andits customer communities:• Increased ability to quickly detect and repair troubles in the distribution

system.• Improved safety through HART-enabled remote monitoring, calibration,

and validation. Performing these tasks remotely enabled DWSD toreduce field crews’ need to enter potentially hazardous meter pits.

• Greatly enhanced value from existing instrumentation without having torely on communications technologies that are not as well field-provenas HART and that require steep investment and risk.

• Greater accuracy in readings throughout the water-distribution system,largely due to HART’s ability to preserve the full accuracy of the mea-suring element in a digital format.

• Range switching and totalization with a single instrument through HART’sdigital transmission of multiple variables.

• The ability to drive computational functions to the field device (e.g., total-ization), which frees the higher-level PLC/RTU for tasks such as moni-toring equipment health.

• Fault tolerance through the ability of HART instruments to retain a his-tory of their readings. In addition, the system’s packet radio networkreroutes signals in case of a node failure.

• Creation of a computer-based historian, which facilitates analysis andreduces paper records.

The Power of HART


software to configure the PLC/RTU formonitoring and operating a particularmeter, and we upload those operatingparameters each day and store them inthe historian, along with the HARTdevice serial numbers and communica-tion statistics. That way, we know theconfiguration of the system each dayand when it changes.”

The AMR/SCADA system is designedto accept readings from up to fourflowmeters and four pressure devicesat each metering point, each of whichis capable of measuring and digitallytransmitting multiple variables. Inkeeping with the goal of fault-toler-ance, the devices, although connectedin a common loop, are wired to thePLC/RTUs in a star topology, so if asingle device or instrument cable fails,it can be taken out of the loop at theaboveground PLC/RTU.

The fault-tolerant philosophy extendsto the PLC/RTUs and the packet radionetwork as well. “The system operateslike the Internet,” says Green. “The mes-sages going back and forth are like e-mail. Each radio acts as a repeater for itsneighbors and automatically reroutesmessages around a radio that fails or thatis suffering interference.”

The customers feel better about all this.“The municipalities that purchase waterfrom DWSD receive the data from theirmeters directly rather than from theDWSD head end,” adds Montgomery.“This assures customers that DWSD isnot adjusting or manipulating the data.”

Cesar Cassiolato, manager of pressuretransmitters for Smar, notes that his com-pany’s differential pressure transmitters(Figure 2) are designed to retain totaliza-tion, even in the event of a power loss.“There’s no reset upon loss of power.When the power returns, you can con-tinue to totalize correctly,” he says.

That meant DWSD could rely onHART. “So we decided to have theHART instrument perform the integra-tion of rate to volume, rather than the

PLC/RTU calculating a volume by scan-ning instantaneous flow rate values fromthe HART loop,” says Green. “In addi-tion, the HART instrument/meter inte-grates far more frequent readings than

the PLC/RTU, so the values are muchmore accurate. This freed up thePLC/RTU to do all the instrument healthmonitoring and store 31 days of 5-min.meter readings.”

As part of that monitoring, HARTallows the PLC/RTUs to detect the typesand brands of instruments on the networkand collect their serial numbers each dayfor a permanent record of equipment thatcan be used in billing disputes and toquickly identify faulty equipment.

So Far, So GoodOverall, the utility is happy with thenew system, but it hasn’t attempted to

quantify the payback on the project.“The continuing controversies over theaccuracy of our meters can be bottom-less pits in terms of time and money,”says Green. “With the new system,DWSD is seeking an end to those dis-putes. Estimated bills that err in favorof the protesting customer have beenreduced substantially.”

Other networking technologies suchas Foundation fieldbus and Profibushave matured considerably since 1996,when DWSD began piloting its sys-tem. Nevertheless, Green says that hewould still use HART, even if the pro-ject were beginning today. “I knowthese newer fieldbus technologies arethe hot thing right now, but it couldhave cost us twice as much money,”he says. “HART does the job for us,and it’s done on our standard equip-ment that was already installed – youdon’t pay extra for it. It certainly wasideal for what we wanted to do.”

Looking ahead, Green noted thatDWSD is building a SCADA systemfor controlling its treated water trans-mission system and wastewater collec-tion system, which includes new sewermeters. “Once our customers are sat-isfied with the water meters of the dis-tribution system, we want to integrateour 54 sewer meters into the SCADAsystem. Much of the equipment on theprocess control SCADA system also isHART-capable, so we definitely wantto bring them in,” says Green.

For more information on this appli-cation, go to www.hartcomm.org. ◊

“I know these newer fieldbus technologies are the hot thingright now, but it could have cost us twice as much money.”


HART-enabled devices allow DWSD to distribute total flow computationresponsibilities to the processors of thedifferential pressure transmitters and the magnetic flowmeters in the vaults,reducing the load on the PLC/RTUs.

Figure 2: Took a Load Off

The HART Plant of the Year Award is an annual award presented to compa-nies that use the real-time communication power of their HART devices.The HART Communication Foundation asked its members and CONTROLmagazine readers to nominate plants that are using the power of HART tech-nology. A panel of HART Communication Foundation officials and CONTROL editors reviewed the submissions, interviewed the finalists, andselected the 2003 HART Plant of the Year.

How DWSD Won


XI

ant to run your plantmore efficiently? Would

you like to set up a better,more automated maintenance manage-ment program? Are you trying to obtainasset management information fromyour plant instrumentation?

Maybe you’d like to avoid processdisruptions. Or keep your plant fromcatching fire and blowing up.

A level transmitter at a Midwestrefinery was short-circuited by conden-sation and created an erroneous 4-20mA signal. The operator was suspi-cious, but no one could find a problemuntil the tank overfilled and shut theentire plant down. The process disrup-tion cost $300,000.

If the system and level transmitter hadbeen HART-enabled, the erroneous sig-nal could have been detected and theoperator would have been alerted to theproblem before it shut down the plant.

You can create those kinds of capa-bilities in your plant. You may alreadyhave much of what you need to get started, particularly if you pur-chased new smart field instrumenta-tion in the past 10 years. That’sbecause just about every smart fieldinstrument built these days is capableof HART Communication.

And if you have devices with HART Communication, you also havea good start on what you need to runyour plant more efficiently. You’reready to begin an asset managementprogram, obtain early alarms on pro-cess upsets, and increase the reliabilityof your processes.

What’s more, it won’t be a major investment to obtain the infor-mation you need, because it’s alreadythere, ready to be accessed via HARTCommunication.

More Than MaintenanceMaintenance technicians appreciateHART because it makes their jobs eas-ier. Techs can interrogate devicesdirectly from the control room, elimi-nating many unnecessary trips out intothe plant.

What you may not realize is thatsimplifying maintenance and calibra-tion tasks is just the tip of the iceberg.Your HART devices also have thepower to push your existing plantinstrumentation and control systemsinto the 21st Century.

You can use HART technology toget started in asset management, forexample. HART devices have all theinformation you need to determinedevice status, health, and the need forfield maintenance. HART devices canalso determine the health of other pro-cess equipment, such as control andsafety shutdown valves.

The Gainesville Regional Utility,Gainesville, Fla., uses HART Commu-nication to diagnose instrumentationproblems and reduce unnecessary trips to the field. The data is fed toasset management system softwarefrom Emerson Process Management.

Operators at its John R. Kelley Gener-ating Station (Figure 1) can checkmany process problems by examiningasset management data from a PC.

For example, if an operator suspectsa transmitter is not zeroing out, he cancheck the asset management systemhistorical data. If there’s a differenceof 5% or more between the process signal and the HART data, the opera-tor knows a problem exists, and some-one must physically check the transmit-ter and associated equipment. Moreoften than not, the utility will report the problem is a leaking valve, found long before the consequences become

HART Communication: It's Not Just for Configuration Anymore

Leverage Your Assets

WW

HART diagnostics mean technicians at the John R. Kelley Generating Station, Gainesville, Fla., make far fewer futile trips up the seven-story heatrecovery generator to check out questionable field devices.

Figure 1: Powerful Intelligence

serious and cause a system breakdown. “After nearly a year of working with

the HART-capable instrumentationinstalled as part of a re-powered 110MW combined-cycle generating plant,our reliance on the unit’s asset man-agement software package continuesto grow,” says Terry Gordon, instru-mentation supervisor. “It enables us todo a lot more things a lot quicker, withfewer personnel than we could by fol-lowing conventional instrument main-tenance procedures.”

One of the finalists for this year’sHART Plant of the Year Award, aSolutia plant in Chocolate Bayou,Texas, that started up in 2000, has lotsof HART-enabled instrumentation.All the HART data is logged to anAspenTech data historian and to anasset management system. “Ourdesign decision was to use as muchsmart instrumentation as possible,”says John Forbis, Engineering Fellowat Solutia’s Integrated Nylon Div., St.Louis. “Ninety-nine percent of allinstruments are HART-enabled. Theonly non-HART instruments are onOEM systems, such as chillers and aircompressors. We tried another com-munication technology, and it just didnot work for us.”

A British Petroleum ethylene plantin Cologne, Germany, has about 2,000HART-enabled instruments and about800 HART-enabled control valvesintegrated with its DCS. “We plan touse condition-based preventive main-tenance implemented via the FoxboroDCS and HART to reduce downtime,”says Helmut Schult, DCS site man-ager. “Specifically, we are configur-ing the system to automatically sende-mails describing impending prob-lems to our maintenance department.”

HART Communication is beingused by many companies to acquiredata for SCADA systems and DCSs.Although the traditional 4-20 mA out-put from each HART transmitter con-

tains the basic flow, temperature,level, or pressure signal, the digitalHART data superimposed upon the 4-20 mA signal contains much moreinformation. Depending on the device,the digital signal can contain 40 ormore data items.

After a HART-enabled device iscommissioned and installed in a plant,it provides those data items 24 hours aday, continuously. All you have to dois communicate with the device.

The HART of the MatterWhat can you do with all that data?Here are a few ideas:• Asset management: HART instru-

ments contain data on the health andstatus of field assets, plus additionalprocess variables. Software is avail-able from several vendors to acquiredata directly from the HART fielddevices to track calibration and con-figuration changes, and keep recordson instrument changes for compli-ance purposes. Asset managementsystems can use the additional pro-cess variables to directly read flow,

level, pressure, and temperature datato be used for compensation, envi-ronmental check, or other purposes.

• Acquire process data: HART allowscontrol and other systems to obtaindigital process data directly fromfield devices. For example, the Solu-tia plant at Chocolate Bayou usesHART technology to acquire analog

inputs for a Triconex triple-modularredundant system used for safetyand emergency shutdowns. “Whenthe same signal needs to go to ourcontrol system and the Triconexsafety system, we use a signal split-ter/isolator from Moore Industries,”says Bart Propst, process controlengineer. “The Moore devicereceives a 4-20 mA signal from aHART instrument and sends 4-20mA outputs to the control systemand another 4-20 mA signal createdfrom the HART data to the safetysystem.” This lets them use the same4-20 mA sensor for control, safety,and shutdown, and still maintainsignal isolation.

• Improve product quality: HARTdata can be used to improve pro-cess dynamics and product quality.The Solutia plant in ChocolateBayou acquires process data frommultivariable HART transmitters.Forbis says they use Valvelinksoftware to do advanced testingand trim key valves to improveprocess performance.

• Manage maintenance: At the AirProducts and Chemicals plant inBaytown, Texas, the asset manage-ment system keeps track of 1,000transmitters and 150 valves usingHART data. “Plant personnel useasset management for routine trou-bleshooting of process issues, recal-ibration, and verifying valve opera-tion relative to the original valvesignatures,” says Mark Lusignia,instrument engineer.

• Real-time diagnostics: When prob-lems arise with a field instrument,the array of diagnostic informationavailable in HART devices makes itpossible to diagnose many problemsfrom a PC screen. In some plants, halfof the times an instrument tech isasked to go out into the plant to checkan instrument, the result is “no prob-lem found.” Being able to diagnose

“After nearly a year of working with HART, our reliance on the asset management software continues to grow.”

XI I

Top 10 HART Apps

1. Configuration2. Commissioning3. Calibration4. Diagnostics5. Multivariable process data6. Process/device alarms7. Signal verification8. Redundant signals9. Data for SCADA applications

10. OPC-compliant data

instrument problems remotely savestime and improves worker safety.

For example, the GainesvilleRegional Utility uses HART com-munication to verify the conditionand operational status of instrumentson top of a seven-story heat-recov-ery generator and other inaccessiblepoints. “It would take a technicianup to an hour to go out into the plant and check a single instrument,”says Gordon.

• Diagnostic alarms: When a controlsystem depends on a 4-20 mA signalalone, an operator has no way tocheck the accuracy or validity of datawhen a problem is suspected. WithHART-enabled systems, software canbe set up to automatically look for adevice status problem or a perfor-mance problem and sound alarmslong before a problem can be detectedin the 4-20 mA loop current.

• Minimize scheduled downtime: GSKPharmaceuticals in Irvine, Scotland,also a HART Plant of the Year final-ist, wanted to reduce the frequency of

calibration for 122 critical devicesfrom once every three months tosomething less often. It takes fourhours to calibrate each device, andfour times per year seemed to be toofrequent, but they had no way ofknowing how often calibrations werereally necessary.

The plant used HART data to col-lect device information and runonline diagnostics. “After a year-and-a-half evaluation period, HARTdata showed that the calibrationcycle could be at least doubled toevery six months,” says Ian Allen,instrument engineer. “We also gotmore accurate information as towhen a device actually did fail, asopposed to waiting for the next cal-ibration, so it could be repaired orreplaced immediately.”

Where Do You Go From Here?For companies building new green-field plants, the choice might be sim-ple: buy only HART-enabled fieldinstruments and system components

and enjoy the benefits of HART Communication from the beginning.HART will simplify installation,startup, calibration, and maintenance,and provide a cost-effective low-riskfoundation for an intelligent instru-ment network for the entire plant.

For companies that already haveexisting plants with legacy instrumen-tation, the upgrade path is different.First, take an inventory of all theHART-enabled instrumentation inyour plant. You probably will be sur-prised to find out how many installedHART instruments you have.

Second, map out an upgrade strat-egy. Non-smart field instruments haveto be upgraded and replaced periodi-cally, so make sure that new instru-ments are HART-enabled. Such anupgrade path is quite easy, becausenearly every legacy 4-20 mA instru-ment can be directly replaced with aHART device. What’s more, thereplacement device will require nochange to your existing control system,because the HART device’s 4-20 mAoutput connects to the same terminalsas the legacy device.

When you map out the upgradestrategy, you may find that a particu-lar process unit needs only one or twoinstruments to become an all-HARTsystem. In such a case, you may wantto speed up the upgrade on that unit or swap some HART instrumen-tation into the system from elsewherein the plant.

Third, review the migration strate-gies we show on pages S-12 and S-13, and see how your plant mighttake advantage of its HART instru-ments. Then obtain a HART server,HART-capable multiplexers, HART-enabled I/O, or a similar HART-based system from your instrumentsupplier and begin implementing anasset management, automated main-tenance, device diagnostics, or devicestatus alarm application.

“HART data showed that the calibration cycle could be at least doubled to every six months.”

XI I I

HART communication enables intelligent I/O systems to identify and diag-nose process problems such as:• Loop fault: With a standard 4-20 mA signal, I/O systems can detect a prob-

lem only if the signal is outside the 4-20 mA range, and only if it is con-stant; they can easily miss intermittent problems. A HART system can peri-odically check the 4-20 mA signal to ensure its agreement with the fieldI/O device. It detects intermittent problems and performs loop tests when-ever needed.

• Device failure: With ordinary transmitters, I/O can detect catastrophicdevice failure only if the 4-20 mA signal is outside the normal operatingrange. With HART, internal diagnostics can communicate the status of fielddevices in real time, provide early notification of problems, and help youtake action to prevent a process disruption.

• Incorrect reading: When the accuracy of the 4-20 mA signal is impairedby, for example, a bad connection or deteriorating sensor, the host sys-tem can detect the incongruities between the 4-20 mA signal and the addi-tional process variables communicated by the HART protocol. Early detec-tion and analysis of these incongruities can focus maintenance operationsand prevent shutdowns.

Finding Problems

XIV

Critical Facts About HART • Traditional 4-20 mA analog signal is

used for control and/or monitoring.• Digital signal carries additional infor-

mation on the same wiring.• All HART smart devices continu-

ously provide process data for plantoperation—24/7.

• HART provides access to all devicedata while the 4-20 mA analog signalis being used for control.

• Information about the status (health)of the field device and quality of the 4-20 mA signal is in every message.

• The Process or Primary Variable(PV) is transmitted as a 4-20 mA sig-nal and also as a digital value.

• Many devices have measured or cal-culated process variables in additionto the PV.

• The more you communicate withHART devices, the more value youreceive from your investment.

HART Device Data Every HART device, regardless of the supplier, comes standard with theability to communicate 35-40 dataitems you can use to improve youroperations. These data items include:• Process Variable Values

Primary, secondary, and other valuesLoop current value in milliamps

• Device Status & Diagnostic AlertsDevice malfunctionConfiguration changeVariable out of limitsPrimary variable output fixed

or saturated• Device Identification

Instrument tag, device type, etc.• Calibration Information

Date of last calibrationUpper & lower range valuePV dampingLoop current transfer function &

alarm actionWrite protect status

A Choice of Migration StrategiesThere are many ways to benefit fromthe power of HART communicationand leverage the intelligence in yoursmart field devices. The figures showseveral simple and cost-effectivemigration strategies to get more fromcurrently installed HART equipment• Point-to-Point Strategy: This is the

most common way HART is used.The communication capability ofHART-enabled devices allows themto be configured and set-up for spe-cific applications, reducing sparesinventory and saving time and money

in commissioning and maintenance.Connecting to the 4-20 mA wires, youcan interrogate a device from remotelocations for diagnostic information.

• HART-to-Analog Strategy: Signalextractors communicate with HARTdevices in real time to convert theintelligent information in thesedevices into 4-20 mA signals forinput into an existing analog controlsystem. Add this capability onedevice at a time to get more of thepower of HART.

• HART-Plus-Analog Strategy: NewHART multiplexer packaging solu-

Unleash the P

Point-to-Point Strategy• Part-time connection• Single device

HART-to-Analog Strategy• Real-time process variable data• Device diagnostics conversion

Analog + HARTHART process dataconverted to 4-20 mA

HART-• Rem• Cen • Off

HART value More HART value

Analog DCS/PLC

Migration Strategies for HA

To analog control system

Existing system I/0

Signal extracter

Asset mHART for device configuration

ower of HART

XV

tions make it easy to communicatewith HART devices by replacing yourexisting I/O termination panels. Youranalog control signal continues on tothe control system but the HART datais sent to a device management sys-tem providing valuable diagnosticsinformation 24/7. Although the con-trol system is not aware of the HARTdata, this solution provides access todevice diagnostics for asset manage-ment and process improvements.

• Full HART Integration Strategy:Upgrading your field or remote I/Osystem provides an integrated path to

continuously put HART data directlyinto your control system. Continuouscommunication between the fielddevice and control system allowsautomatic detection of problems so corrective action can be taken before there is negative impact to the process operation.

• HART-to-Plant-Network Strategy:HART OPC server software toolsprovide a simple, cost-effectivemeans of passing HART data ontoyour plant Ethernet network to OPC-compliant applications anywhere inthe plant.

Serve HART to Plant Networks The HART Communication Founda-tion has developed the HART ServerTool to facilitate serving HART data toplant networks and other high-levelOPC-compliant applications. The toolprovides easy access to HART devicedata anywhere on a plant network.• Allows several applications to

simultaneously access data in aHART device.

• Enables popular HMI and trendingpackages to access HART data.

• Connect to one or a thousand devicesusing common HART I/O systemsand interfaces.

• Cost-effective and easy to set-up and use.

• Can put HART data on your desktop, PDA, e-mail system, etc.

• Created and supported by the HARTCommunication Foundation.

What to Do?HART communication technology issimple, easy to use, low-risk, and cost-effective. As with any journey, takingthe first step is important. Here’s howto get started:• Visualize one or more of the many

ways HART communications couldimprove operations in your plant.

• Identify your installed HARTdevices to confirm that key measure-ments are included. If not, map out a plan to make all devicesHART-capable.

• Provide HART technology trainingto your staff.

• Explore HART solutions with yoursuppliers to determine your bestmigration strategy.

• Contact the HART CommunicationFoundation or visit the Foundationweb site, www.hartcomm.org, formore information and for specificcost-effective solutions you can useto Unleash the Power of HART.

-Plus-Analog Strategyote device access

tralized device diagnosticsf-line data access

Full HART Implementation Strategy• Real-time and integrated data• HART data part of DCS• Full HART data access

HART-to-Plant-Network Strategy• HART data to LAN• OPC-compliant• Enterprise-wide access

Maximum HART value

HART data

Ethernet-TCP/IP

HART OPC server

SCADA Historical trending SPC/SQC MIS/ERP

OPC clients

HART-enabled I/O

I/O with muxRS-232 interface

HART OPC Ethernet

RT Integration

anagement system

I/O with mux

HART-enabled DCS/PLC/PAS

HART

data HART-enabled I/0

HART data

XVI

n essence, HART’s value proposi-tion is moving more data from theprocess into the control system with

an infrastructure you already own, thenleveraging that information to increaseplant efficiency. A range of connectionoptions make it relatively easy.

If your plant has a DCS connected to a large number of HART-enabledinstruments and field devices, theHART signal superimposed on the 4-20 mA wiring is readily available andcontains a wealth of useful process anddevice diagnostics information.

Control Systems Get HARTMost of the major DCS and control sys-tem vendors already have HART Com-munication capability in their newersystems, and many have upgrade pathsfor older systems. For example, in Maythe Foxboro division of Invensysannounced new I/A Series HART mod-ules. Each module can accept up to eight4-20 mA inputs and fully integratesHART Communication.

The Foxboro upgrade has alreadybeen used to implement asset manage-ment and preventive maintenance at aBritish Petroleum ethylene plant inCologne, Germany. The plant hasabout 2,000 HART-enabled instru-ments and about 800 HART-enabledcontrol valves. “We purchased newinput and output modules and installedthe newest version of the Foxboro I/Asoftware,” says Helmut Schult, BP’sDCS site manager at the Cologne plant.“We then installed the modules, andconfigured the I/A system to recognizethe modules.” There was no need tochange field devices since they werealready HART-capable.

This kind of system offers full-time,real-time HART data integration with

the control system and higher-level sys-tems. While the several-second latenciesof other approaches are usually quiteacceptable in process applications, con-trol systems optimized for HART Com-munication can reduce latency times toabout 0.4 sec. per point, depending onthe network configuration.

Honeywell’s Experion PKS controlsystem offers eight-channel HART ana-log-input and analog-output modules.Both modules scan the standard 4-20mA analog signal and the HART digi-tal signal. The HART digital data ismade available to the control systemover ControlNet.

“HART device information isscanned from each device and madeavailable for display, logic, control, ortrending,” says Joe Serafin, Experion

PKS product manager for HoneywellIndustry Solutions.

ABB supports the HART protocolthrough its Industrial IT controllers.

“HART instruments are connected tothe Industrial IT I/O system,” explainsMartina Walzer, marketing managerof fieldbus technologies for ABB.“HART information is then tunneledto the controller via Profibus.” HARTCommunications is also available on ABB’s legacy control systemsincluding Advant, Symphony, andFreelance 2000.

HART devices can communicatewith Siemens’ systems through itscompatible remote I/O, HART modem,HART interface, or HART multiplexerproducts, and a HART I/O moduleis offered as part of the APACS+ control system.

Emerson Process Management deliv-ers its DeltaV automation systems withHART as a standard. “We feel so

strongly that HART is a good protocolfor those not considering Foundationfieldbus that the DeltaV automationsystem analog I/O is only sold with

New Products Seamlessly Connect HART Field Devices to Any Control System

Powerful Connections

II

DIN rail-mounted multiplexers can be interconnected to provide communica-tion with as many as 7,905 HART devices.

Figure 1: Multiplexers Link HART to Any PC

HART capability,” says Ron Eddie,vice president of technology for Fisher-Rosemount Systems.

HART functionality is also availableon Westinghouse Ovation systems andon Provox and RS3 systems. On oldergenerations of Provox it is only neces-sary to upgrade the I/O terminal stripand the analog I/O card. For the oldergenerations of RS3 systems, it is neces-sary only to upgrade the I/O electronics.

Clever Devices Fill GapsIf your existing DCS is not HART-enabled, and if immediate plans do notcall for a new DCS or an upgrade toyour DCS to make it HART-capable,there are many other options. Signalextractors can access portions of HARTdata from a device and send it to your plant control system via 4-20 mA signals and/or discrete outputs.

The 2002 HART Plant of the Year(page S-21) makes extensive use of

Moore Industries’ SPA loop monitorand alarm. Signal extractors like theSPA extract the HART data superim-posed on a 4-20 mA signal and retrans-mit virtually any combination of the

process variable values, the status anddiagnostic alerts, and the device identi-fication information contained in theHART data.

Many control systems already havethe capability to communicate via adigital fieldbus or an OPC interface. A low-cost way to connect HARTinstruments and control valves to thesecontrol systems is through a commu-nications gateway. Multiplexers, RS-232 interfaces, and gateways that con-nect HART to Ethernet, Modbus, andProfibus are widely available.

The Viator HART PC modem fromMACTek, for example, attaches to a PC serial port and allows the PC to communicate with HART devices.The modem is a good interface forSiemens’ Simatic PDM and other assetmanagement software.

Pepperl+Fuchs has a choice ofHART multiplexers that convertHART data to RS-485. This serial data

can be recognized by a number of PC-based software programs includingAMS from Emerson, Cornerstone fromApplied Systems Technologies, andPepperl+Fuchs’ PACTware. A typical

connection scheme combining masterand slave multiplexers (Figure 1) canconnect as many as 7,905 HART fielddevices to a PC.

OPC Serves It Up A more versatile and powerful methodof connecting HART instruments andcontrol valves to existing control sys-tems is through the OPC-compatibleHART Server Tool (Figure 2). Inex-pensive and simple to implement, allthat is required is a PC, OPC serversoftware from the HART Communica-tion Foundation, and a multiplexer orserial modem.

The PC can be anything that runsWindows 95/98/NT/2000, from a full-blown desktop machine to a rack-mounted device. The PC does notrequire a keyboard or a display to runthe HART Server Tool software pro-gram, so it can be very compact, indus-trially hardened, and designed for lowpower consumption.

The HART Server Tool softwarecommunicates with the HART devices,and converts HART data to OPC data.This OPC data can then be communi-cated to any software package with OPCclient communications.

Virtually all HMI, asset management,and soft logic software has a built-inOPC client interface, so the HARTServer Tool can be used to connect justabout any application to HART fielddevices. The HART server also allowsseveral systems to access data from aHART device at the same time, and itcan even be used to transmit data tohandheld wireless devices such as PDAs.

Whether starting small by extractingHART data on a limited basis for a spe-cific purpose or diving in with a fullyHART-capable DCS, using the informa-tion you already have available fromyour installed base of HART fielddevices is a powerful, cost-effective wayto leverage your plant’s assets into the21st Century.

“Signal extractors can access portions of HART data from adevice and send it to your plant control systems.”

XVI I

Ethernet-TCP/IP

HART OPC server

SCADA Historical trending SPC/SQC MIS/ERP

OPC clients

HART-enabled I/O

I/O with muxRS-232 interface

HART data

The HART OPC server provides a standard interface between HART devicesand any OPC client.

Figure 2: At Your Service

XXIV

or its recognized success withHART-enabled instrumentation,as well as its commitment to

future system enhancements usingHART technology, the DuPont chlo-ride-processing facility in DeLisle,Miss., has been selected the 2002HART Plant of the Year.

The HART Communication Founda-tion asked CONTROL readers and itsmembers to tell us about plants that areleading the way in using the power ofHART technology. Many worthy nom-inations were received. A panel of Foun-dation officials and CONTROL editorsreviewed the submissions, interviewedthe candidates, and selected the HARTPlant of the Year.

Three main factors led the judges toselect this DuPont application as thisyear’s winner. First, the plant uses thepower of HART even though it does nothave a HART-enabled control system.Second, HART Communication is usedfull-time in daily operations. Finally, theplant is migrating to using HART infor-mation for additional cost-effective solu-tions that deliver significant benefits tothe enterprise today and into the future.

The DeLisle plant produces DuPont’sproprietary R-104 Ti-Pure titaniumdioxide (TiO2). TiO2 is a white pigmentused in paint, plastics, and productswhere color retention is desired. TiO2

absorbs ultra-violet light energy and italso possesses light-scattering proper-ties that enhance whiteness, brightness,and opacity.

TiO2 production requires a sophisti-cated manufacturing process thatincludes chemical reduction, purifica-tion, precipitation, washing, and calci-nation of titanium, iron, and other metalsulfates. “DuPont determined that thebest way to control and monitor these

processes was with HART-enabledinstrumentation,” says Joe Moffet, pro-ject manager with DuPont. “Virtually allof the plant instrumentation is HART-enabled, and this includes instrumentsused to monitor and control temperature,pressure, level, and flow.”

The DeLisle plant control and instru-mentation system uses the HART com-munications protocol in a variety ofways. HART data is used as an input to

the safety interlock system and as aninput to the control system. Like mostother users, DeLisle personnel use hand-held HART communicators for config-uration, calibration, and troubleshoot-ing. And as we’ll see, future plans callfor HART data as a key input to an assetmanagement system.

Normal plant operations are con-trolled by a Honeywell TDC-3000 distributed control system (DCS), and

DuPont Uses HART Data to Satisfy Safety Interlock System Valve Test Requirements

HART Plant of the Year

FF Most safety interlocking at the DeLisle plant is implemented through a dedicated DCS controller, but certain processes must be equipped with a hard-wired relay safety shutdown system. Many of these processes use HART-enabled pressure and temperature transmitters. Each of these transmitterssends a 4-20 mA process variable signal to a Moore Industries SPA loop mon-itor that decodes the HART data superimposed on the 4-20 mA signal.

The SPA then sends a process variable signal derived from the HART datato the DCS, and it also sends fail-safe alarm contacts to the hard-wired relaysafety shutdown system. These alarm contacts are set to indicate high-level,low-level, and the presence or absence of the HART signal.

HART-enabled instruments allow DuPont to operate the plant in a safe andefficient manner. “HART and the SPAs provide a solution that unlocks a wealthof diagnostic and process information in the positioners and transmitters,”saysDuPont project manager Joe Moffet. “This information is used to increase reli-ability and minimize the duration of required plant shutdowns.”

DuPont is using this highly efficient TiO2 processing site as a benchmarkfor other facilities because of its outstanding compliance with safety, health,and environmental requirements. DuPont plans to fully exploit the availableHART data with an asset management system that will provide automated par-tial valve-stroke testing, predictive maintenance alerts, and comprehensivemanagement of the plant instrumentation system.

Fail-Safe System Relies on HART Communication

the DCS is also used with a hard-wiredrelay system to control safety shutdownsystems. Although future generations ofHoneywell DCSs will be able to directlyreceive and transmit HART data, thepresent DCS does not have HART com-munications capability.

DuPont needed to add intermediateinstrumentation to extract relevant data

from the plant’s HART instruments,and Moore Industries’ SPA HARTloop monitor and alarm is used for this purpose.

One of the main reasons DuPontselected the SPA instrument is thatMoore Industries submitted the SPA toan independent third party for failuremodes, effects, and diagnostic analysis(FMEDA). “FMEDA is a detailed cir-cuit and performance evaluation thatestimates the failure rates, failuremodes, and diagnostic capabilities of adevice,” explains Bud Adler, director ofbusiness development with MooreIndustries. “Using the reliability datafrom the SPA’s FMEDA report, DuPontis able to verify that required safetyintegrity levels (SILs) are attained.”

HART Increases UptimeTiO2 production involves many criticaland potentially hazardous processes, soreliable operation of the safety shut-down systems is of paramount concern.DuPont uses HART to provide keysafety interlock inputs to the DCS andto the hard-wired relay system.

The safety interlock system has anumber of on/off control valves, eachequipped with a HART-enabled valve-stem positioner. Each control valve is

connected to the DCS via a 4-20 mAsignal sent from the DCS to control thevalve position. HART data is superim-posed on the 4-20 mA connection, andthe SPA loop monitor and alarm extractsthe valve-stem position from the HARTdata. The SPA then sends the actualvalve-stem position data to the DCS viaan additional 4-20 mA connection.

The DCS compares the valve controloutput signal to the HART valve-stemposition data to ensure proper position-ing. This data is used to verify correctfunctioning of the valve in normal oper-ations, and to test the valve whenDuPont performs periodically requiredplant shutdowns to verify operation ofthe safety shutdown system.

The HART data allows DuPont totest valve safety interlock operationfrom the control room. Control roomoperators place the appropriate DCSoutput in manual mode and adjust the4-20 mA control valve output signal toopen and close the valve. The SPAsends a 4-20 mA signal derived fromthe HART data back to the DCS to ver-ify valve position.

Consider the alternative: If the valve-stem position data was not available atthe DCS through HART and the SPA,DuPont would have to station an instru-ment technician at each valve toobserve valve operation. The technicianwould have to observe valve travel, andcommunicate this information to con-trol room personnel. “There are over100 control valves equipped withMoore SPA loop monitors, so valvesafety interlock testing would be alabor-intensive and cumbersome oper-

ation without HART Communication,”observes Moffet.

Online Tests Reduce OutagesDuPont has plans to take valve testingto another level—a level that willreduce the number and lengths of out-ages required for safety interlock test-ing. Certain valve testing requirementsfor safety interlock systems can be metwith partial valve-stroke testing ofemergency shutdown valves duringnormal operations. Performing thosetests during normal operations meansfewer shutdowns are required, and therequired tests take less time so the shut-downs can be shorter.

Partial valve-stroke testing duringnormal operations is a procedure,either manual or automated, used tostroke a valve over a small percentageof the valve’s total travel range. Forexample, a safety interlock valvemight be fully closed during normaloperations. Partial valve-stroke testingcould be used to move the valve to aslightly open position. This would ver-ify valve operation without affectingnormal operations.

The present system could be used toundertake manual partial valve-stroketesting, or an upgraded system could beused to implement automated partialvalve-stroke testing.

“We are currently evaluating devicemanagement system that would be ableto directly accept data from all of ourHART instruments,” Moffet says, “andthe system could be used to implementautomated partial valve-stroke testing.”

Other plans call for using additionalSPA capabilities to monitor the diagnos-tic status of the valve-stem positioners,to provide alarm on low valve-operatingair pressure, and to provide relay con-tacts for open and closed valve position.For more critical applications, one-out-of-two (1oo2) and two-out-of-three(2oo3) configurations can be used toincrease availability and reliability.

“Virtually all of the plant instrumentation is HART-enabled...temperature, pressure, level, and flow.”

XXV

Major Benefits of HART Communication for DuPont

1. Expedites testing of safety interlock valves, shortening plant shutdowns.2. Provides fail-safe inputs to the hard-wired relay safety interlock system.3. Allows remote configuration and ranging of virtually all instrumentation.4. Reduces the number and duration of shutdowns by using partial

valve-stroke testing.5. Establishes the foundation for an asset management system.

I

Use the Power of HART

ook under your nose.Though rarely in thenews, HART has thelargest installed base

of all digital field communications protocols in the process industries. Asignificant percentage of the fielddevices in your plant are probablyHART-enabled, and you almost cer-tainly are or will soon be under pres-sure to bring more information fromthose devices to your control, assetmanagement, and enterprise systems.

But many end users haven’t madethe connection. HART can do muchmore than serve as an occasionalinformation bridge for device config-uration and troubleshooting. In manyapplications it can serve as the pri-mary means of two-way communica-tions for system integration.

Using the power of HART commu-nication is like letting the genie outof the bottle.

Resources Are RisingWhen HART technology was intro-duced in the early 1990s, control engi-neers realized information from intel-ligent devices was valuable, but at thetime there was no easy or clean wayto integrate this data into control sys-tems. For years, valuable informationin these devices has languished inparts of subsystems, in limited appli-cations such as maintenance and loopcheck-out tools, or ignored altogether.

Meanwhile, the business situationin the process industries has changeddramatically, creating the need tomaximize any and all investmentsand assets. Reduced manpower, bud-get cuts, higher profit requirements,and increased global competitionhave users looking at all possible

means of capturing information thatcan improve the operation and finan-cial results of their plants.

Highly visible discussions havepromoted fieldbus capabilities andthe value of additional informationfrom remote communications. Butaccess to information is one thing—the ability to get it full-time and with-out pain is another.

Over the past 10 years, companiesof all sizes have created HART-capa-ble devices that operate in a hybridfashion. These devices offer a power-ful bridge between the analog anddigital worlds by using the 4-20 mAsignal to feed the control system asinitially designed, and simultaneouslycarry digital HART information—which in most cases is free—withadditional process variables, enhancedalarms and diagnostics information.

HART Communication Foundation(HCF) members around the globehave created a cadre of instrumen-tation that collectively provides all thepieces of the puzzle needed to addressthe many needs of process control.And the HART protocol continues toevolve as a global standard. Membersrecently approved new HART 6 spec-ifications that expands communica-tions capabilities and is compatiblewith existing instrumentation.

In addition, the HCF has initiateda significant program to educate both

users and suppliers/members on thevalue of full-time HART communi-cation. The HCF web site, www.hart-comm.org, has been redesigned tomake it more user-friendly as well asto provide more user-application anduser-oriented information.

What to DoTake another look at HART as itapplies to your company’s needs.Review your installed base of instru-mentation and your current buyingrequirements as they are likely to showyou have a significant investment inand potential to harness HART.

Talk with your suppliers about howtheir products support the full powerof HART. If they don’t, ask why. Dis-cuss your current installation withyour suppliers to ascertain the degreeof HART compatibility of your sys-tem. Then map out a plan to use yourassets to the fullest.

There is a growing need to use intel-ligent data from the field to addressenterprise improvements such as per-formance, quality, safety, reliability,profitability, maintenance, and man-agement. No one bus or communica-tion technology is perfect for allapplications, but HART may be thesimple, cost-effective, low-risk, high-value solution you need for improvedprocess control—and odds are you’vealready got it.

LL

Ron Helson, Director HART Communication Foundation512/[email protected]

Your Wish Is HART’s Command

II

ost users were attracted to HARTfor instrument calibration and main-tenance, but many don’t realize theprotocol has the power to be the

main digital communication bus for applications such as SCADA, ERP, and asset management. HART providesa wealth of the type of data required by these high-level applications.

Corporations have spent billions of dollars over the pastfew years installing ERP and asset management systems.A tremendous amount of pressure is now being applied toprocess plant managers and engineers to provide data tothese systems. SCADA systems must also be upgraded toimprove performance and reduce costs.

Existing HART instruments can accomplish these tasksin a cost-effective and low-risk manner.

SCADA Can Do More With HARTThe market for SCADA applications continues to grow.According to Russ Novak, director of consulting for theARC Advisory Group, Dedham, Mass., “The worldwideSCADA systems market for the oil & gas and water &wastewater industries exceeded $650 million in 2000. Thismarket will reach almost $780 million by the end of 2005,growing at an annual rate of 3.5%.” HART devices canbe expected to play a significant role in this growth.

Periodic instrument adjustment is a necessity in pro-cess plants, but continuous monitoring can be a require-ment for certain applications. One of these applicationsis a SCADA natural gas metering system designed byArcom Control Systems, Kansas City, Mo., for the TejasCalumet gas plant in Louisiana (Tejas is an affiliate ofRoyal Dutch Shell).

The Calumet gas plant receives raw natural gas fromoffshore pipelines and separates out liquids such aspropane, ethane, and methane. The plant consumes natu-ral gas in the process and is charged for the energy usageby its suppliers. “Our firm designed a gas flow measure-ment system for Calumet to internally verify the amountof energy used in various parts of the process. Calumetneeded to provide check metering for gas usage,” says JonTandy, a project engineer for Arcom.

The gas flow measurement system uses a combinationof protocols to gather and process data. “Our SCADAsystem acquires gas composition data from Applied

Automation gas chromatographs and calculates com-pressibility constants using AGA8 calculations. Thisinformation is downloaded to the HART-compatibleRosemount 3095FT flow transmitters via the HtNodeevery three hours. Production data is also acquired fromDaniels 2500 flow computers and RTUs,” adds Tandy.The HtNode is a protocol translator that allows HARTdevices to communicate via Modbus.

The 3095FT flow transmitter was chosen by Calumetbecause it provides high accuracy, is physically smallerthan most flow computers, and has a competitive price.It provides differential pressure, absolute pressure, andtemperature inputs on the same transmitter. The HARTprotocol is used for communication of process variables

and for the acquisition of device-specific historical andconfiguration data.

Accurate measurement of gas flow with the flow trans-mitters is only possible with continuous composition feed-back. “The gas chromatographs yield information withrespect to gas composition. The SCADA system uses thisdata to continuously calculate correct parameters for theflow transmitters. These parameters are sent to the flowtransmitters via the HtNode so that that the flow calcula-tions are adjusted dynamically based on composition ofthe natural gas,” Tandy says.

Another SCADA application makes use of HART’scapability to simultaneously transmit both 4-20 mA anddigital signals. “HART devices were the best choice fora safety shutdown system installed in a process plant.Two independent control systems were required because

HART Delivers Process Data to SCADA, ERP, and Asset Management Systems

MMCall for Information

Figure 1: Get Connected

HART-enabled field devices like the ones in this safety system

offer both a conventional analog signal (for control) and a

digital signal (for information).

digital fieldbus protocols have not been approved by thestandards organizations for shutdown applications,”observes James Gray, director of I/A systems marketingfor Invensys Process Systems, Foxboro, Mass.

In this application (Figure 1), each field device musthave the capability to transmit a signal to each of the twoindependent control systems. “A Foxboro I/A system isthe DCS and a PLC was used for the safety shutdown system. In the I/A system, the fieldbus module interfacesto the HART digital communication signal from the fielddevice. The PLC uses the 4-20 mA signal from the fielddevice for its analog I/O as the primary input of the safetyshutdown system,” continues Gray.

The DCS analyzes the HART signal information anddistributes this information throughout the control sys-tem. “The HART protocol is used for diagnostic infor-mation from the field device. This information can pro-vide an active status word to the system and alert theoperator of a device fault before it impacts the perfor-mance of the process. The status word is integrated intothe analog input block of the control system and propa-gated throughout the control strategy if an error or devicefault is detected,” adds Gray.

If an error is found, the DCS can interact with an oper-ator to correct the problem. “Once an error in the fielddevices is detected, the operator or technician can inter-rogate the field device from the console. Using the toolsof the I/A system’s Technician’s Workbench, a poll com-mand is sent from the operator console to the field deviceto read or perform a series of diagnostics,” Gray says.“These tests validate the condition of the field device andoften eliminate unnecessary trips to the field.”

HART capabilities can also be extended to wirelessSCADA applications. A major Midwest gas pipeline com-pany planned to replace paper chart recorders on its natu-ral gas pipeline with an automated meter reading (AMR)system. The AMR system would have to be capable ofacquiring data from devices within a radius of up to 80 miles, publishing this field data from locations through-out the Midwest to a central host in Tulsa, and integratingthe data with an existing measurement system.

The system architecture diagram (Figure 2) illustratesthe design of the wireless SCADA system. Multivariableflow transmitters provide flow measurement and data logging capabilities. These transmitters communicate via HART over a wireless radio link to a network gateway/multiplexer from Arcom. “Our Director gateway satisfiedall the requirements for the project,” says Tandy. “TheDirector uses HART to acquire real-time and historicalinformation. Data is then published to a central host viasatellite.”

The AMR system uses spread-spectrum radio andsatellite communication to extend the HART networkbeyond the traditional 10,000-ft. distance limitation.Spread-spectrum radios from Freewave Technologies pro-vide the wireless link between the gateway and the HARTinstruments. “The radios allow great flexibility in networkarchitecture through multipoint and repeater configura-tions, as well as providing reliable data transmissionof the HART messages,” Tandy adds. “With the use of

repeaters, HART units can be brought into a single multi-plexer from a radius of 80 miles or more.”

By implementing the HART-based AMR system, thepipeline company was able to realize cost savings in sev-eral ways. The paper chart recorders previously had to becollected and tabulated manually for each monthly billing.

This is now done automatically with ongoing savingsestimated at $1.25 million per year. Because the HARTsignal is transferred over the radio link, there is no needfor a separate remote terminal unit (RTU) or multiplexerat each meter site. One multiplexer serves as a master to32 HART meters and allows data consolidation.

Wireless communication avoids costly cable runs toeach HART meter. The multivariable flow transmitterseffectively combine a traditional flowmeter and three dis-crete instruments into a single instrument, yielding hard-ware cost savings of almost 30% per site. TCP/IP com-munications allow remote diagnostics and configuration,reducing the need for on-site technical support. HARTprovides the communication tool to create an extendedmeter-reading network via spread-spectrum radio andsatellite communication.

“Tests validate the condition of the field device and often eliminate unnecessary trips to the field.”

I I I

Figure 2: HART Works With Wireless

A gateway/multiplexer in this gas metering application acts as a

HART master and publishes data using TCP/IP.

ERP Needs HARTERP and e-business systems from vendors such as SAP,Baan, and Oracle cannot perform as designed withoutextensive information from plant-floor control systems.This information is often available through existingHART devices. Plant engineers can extract data fromthese existing devices and provide it to ERP systems. Theexpenses of purchasing and installing new devices oftencan be avoided.

Many food and pharmaceutical processes require exten-sive recordkeeping with respect to batch parameters.These parameters can include process variables such aspressure, temperature, and level. The multivariable capa-bilities of HART devices can be exploited to extract thesesecondary variables from existing devices.

Batch records should also indicate if each field deviceis operating properly. The status and diagnostic informa-tion available from each HART device can be used toautomatically verify proper operation. The only alterna-tive in most cases is to have a field technician check andverify device operation.

HART Helps Manage AssetsRecordkeeping also extends to instrument calibrationactivities. Asset management programs can use HARTcapabilities to automate much of the calibration and record-keeping required for critical processes.

One provider of Windows-based instrument asset man-agement software is Applied Systems Technologies, FortLauderdale, Fla. Its Cornerstone software is a family ofMicrosoft Windows-based process instrument mainte-nance management tools.

Aventis Crop Science uses Cornerstone software atits plant in Institute, W.Va., to configure and manageits HART-compatible instruments (Figure 3). “Eachinstrument is configured and trimmed in the Aventisinstrument shop prior to putting the device into service,”says Brad Alexander, Applied Systems president. “TheHART protocol makes it easy for the device to be auto-matically added to the Cornerstone database when thefirst connection is accomplished.”

Three of the instrument shops at the site use Cornerstone,and Aventis plans to convert the rest of the shops in the nearfuture. “We use the HART interface with Cornerstone toconfigure the instruments for our use and to track anychanges that are made to these instruments,” says DennyHumphreys, an instrument/electrical technician with theequipment reliability group at Aventis. “These changesmight be made in the field through a documenting cali-brator, in the field though a field communicator, orthrough Cornerstone itself.”

Initial device configuration establishes a baseline foreach instrument that can be compared to later readingsto create a history for the instrument. The baselineincludes not only calibration information, but also deviceinformation such as a user-designated tag number, auser-defined descriptor, and manufacturer’s information.“One specific issue in calibration management that isaddressed by the HART protocol is the ability to posi-tively confirm the identity of the device being calibrated.Prior to smart devices, there was no inherent methodavailable to confirm the unique device identification,which is obviously required to validate the calibrationhistory,” observes Alexander.

This observation is seconded by Aventis. “Using Cor-nerstone with the HART interface has helped us tremen-dously in getting new instruments configured and cali-brated quickly,” adds Humphreys. “Cornerstone also has

a database that is password protected and that automati-cally documents every change that takes place at our site.”

Aventis uses the software in conjunction with HARTinstruments to provide complete management of instru-ment calibration and maintenance. Alexander says, “TheCornerstone HART maintenance station makes it possi-ble to confirm existing configurations, to automaticallydetect any configuration changes introduced in the field,to prepare configuration edits for download to an instru-ment upon next connection, and to reconcile any variancesbetween the instrument database records and the devices.”

The software can also be used to provide remote diag-nostics by periodically polling each instrument to accessdevice status. This information can then be used to alertthe instrument shop and generate repair orders. “We usethe Cornerstone monitor feature with our HART Instru-ment. This allows us to quickly spot any problems with aninstrument including signal spiking, ground loops, or a

“The status and diagnostic information available from each HART device can be used to automatically verify proper operation.”

IV

Figure 3: Manage Change

Instrument maintenance management software can use HART

data to track calibration and configuration changes.

problem with the primary element,” continues Humphreys.The HART protocol and maintenance management

software allow Aventis to use instruments from manydifferent vendors. “The HART interface is not propri-etary so we are not tied to one instrument vendor or onetype of documenting calibrator. Cornerstone is also ableto handle many vendors through the use of modellibraries and calibrator libraries that can be used any-where on the LAN,” Humphreys says. “I have been com-pletely sold on the HART interface for years, but it wasnot until I discovered Cornerstone that the benefitsbecame so very apparent.”

Application Optimizes HART Condition and diagnostic information generated by fieldinstruments can be captured from control networks byonline applications and integrated with an enterprise assetmanagement (EAM) or computerized maintenance man-

agement system (CMMS).One such online application is Asset Management Solu-

tions (AMS) software from Emerson Process Management,Austin, Texas. AMS provides the interface betweenfieldbus devices and maintenance management systems(Figure 4). This allows automatic generation of workorders based on actual device conditions.

The online asset management software gathers datafrom HART instruments and stores it in a device-orienteddatabase. The data is then processed, organized, and presented in graphic displays. The information can be usedto speed unit startups, streamline routine maintenance, andprovide early warning alerts of component failure.

Overall maintenance costs can be further reduced and

process uptime can be increased by delivering field-baseddata directly to an EAM. When AMS is integrated withan EAM system, early predictive maintenance warningscan be provided about potential equipment problems.

Trial-and-error preventive maintenance can bereplaced by prioritized work orders based on actual evi-dence that a repair or replacement is required. Ratherthan scheduling field devices for maintenance based onthe calendar, the EAM system receives notification fromAMS that service is necessary and a work order to thateffect is generated.

Integration of an online AMS with an EAM systemlowers overall maintenance costs and increases processuptime by providing advanced warning about potentialequipment failures. By combining these important maintenance tools, companies can establish a predictivemaintenance environment to keep plants running athigher efficiency with less technician involvement.Potential problems can be corrected before serious damage occurs, and the cost of maintenance can be significantly reduced.

Syncrude Canada, Calgary, Alberta, is using HART andthe AMS system at its oil refinery in Fort McMurray,Alberta. “During the design of our most recent process unit, a 305,000 barrel-per-day vacuum distillationunit, we decided to install all HART smart instrumentsand hook them up to the AMS through a Honeywell DCS,”says Gil Hurtubise, process automation specialist withSyncrude in Calgary.

The AMS system works with HART devices toimprove plant efficiency. “The largest economic paybackis the maintenance efficiency gained by being able toaccess the equipment diagnostics in order to make ourmaintenance more predictive,” adds Hurtubise. “Equip-ment diagnostics also allow us to keep a history of con-trol valve signatures. This becomes a very valuable toolas the equipment ages and also assists in planning whichequipment must come out for maintenance during aplanned process unit outage. It is important, however,that this tool [AMS] be set up as a working system ini-tially and later supported on a dedicated basis throughorganizational structure.”

Another benefit of HART was realized during plantstartup. “Using the HART component of the signalallows you to be much more efficient during final con-struction checks, commissioning loop checks, andstartup,” adds Hurtubise. “It allows you to forgo manyof the point-to-point wiring checks that you would nor-mally make with analog instruments, by making use ofthe digital network to prove the integrity of the wiringinstantly for the entire loop.”

“The HART interface is not proprietary so we are not tied to one instrument vendor.”

V

Figure 4: Leverage Assets

Bringing data from HART instruments into enterprise asset

management (EAM) systems allows automatic generation of

work orders based on actual device conditions.

VI

ost users know HART provides forcommunication of multiple dataitems between field devices and a host controller or computer.

Many also know that integrating additional field devicedata into control or maintenance strategies can improve system performance.

What most HART users don’t know is there is anincredible amount of data that can be communicatedbetween their existing HART devices and control systems.Typical user estimates of available data items range fromthree to 10 values in addition to the process variable. Theactual number is 35 to 40 values depending on the type ofHART device (see sidebar, “Data Items Available forCommunication Between HART Devices and a Host”).

There is tremendous value in the data available fromHART devices. “Many users have little or no idea of themeasurement and process improvements that can be imple-mented through HART devices,” says Warren Meyer, prin-cipal marketing specialist with The Foxboro Co., Foxboro,Mass. “These improvements typically require minimalengineering and can be imple-mented quickly and at very lowcost. These HART devices arelike icebergs—we only seeabout 20% of the functionalityand 80% is hidden from view.”

The most important data itemsavailable from HART devicesare the process variables. Theprimary process variable is con-tinuously transmitted in twoformats: 4-20 mA analog anddigital as part of the HART pro-tocol. The primary process vari-able is also transmitted as a percent of range. Finally, theloop current in milliamps can also be accessed. The loopcurrent reading can be used to validate the signal beingreceived by the controller.

The primary process variable digital value is expressedas an IEEE floating-point number with up to 32-bit preci-sion. This far exceeds the standard 12-bit precision offeredwith most PLC and DCS analog input modules.

High precision can be especially useful in weighing andscaling applications. Twelve-bit resolution yields very

limited accuracy for storage tank weighing systems. Thesesystems often measure weights up to 200,000 lbs. andrequire high precision to resolve the total weight to anacceptable level.

Many existing and most new HART devices have mul-tivariable measurement capabilities. This is true of manypressure and temperature devices; most flow, level, andanalytical devices; and all valve positioners and valve con-trollers. Table I lists common types of multivariabledevices and typical outputs available from these devices.

Up to three secondary process variables in addition tothe primary process variable (total of four) can be simul-taneously transmitted from a HART device to a host in asingle message. This multivariable capability can beexploited in a number of ways.

Multivariables Provide Multi-BenefitsMultivariable transmitters with a digital HART interfaceoffer tremendous functionality and application diversitycompared to instruments with only a 4-20 mA output.Unfortunately, the average user of HART devices only

scratches the surface in terms of using the informationavailable from them.

One of the best ways to improve plant profitability isto use the on-board temperature sensor located in virtu-ally all HART devices. This sensor measures the internaltemperature inside the field device, not the ambient orprocess temperature. The manufacturer uses internaldevice temperature to characterize the output during widetemperature fluctuations, thereby eliminating most of thetemperature-related error of the device. A user can also

Field Devices Offer Much More Than the Process Variable

MMHidden in HART

Table I: Common Multivariable DevicesDevice Primary and Secondary Process Variables*

Pressure transmitter Pressure, temperature, differential pressure

pH transmitter Electrode output, compensation temperature, sensor impedance

Coriolis meter Mass flow, density, temperature, totalized flow

Valve positioner Target stem position, actual stem position, actuator pressure,

output signal to actuator

Temperature transmitter Temperature, cold junction compensation value

DP level transmitter Level, pressure at cell 1, pressure at cell 2,

temperature of capillary fluid

*HART supports up to 256 process variables in a device. However, only four of them can be transmitted in a single HART message.

digitally transmit the on-board device temperature to thecontrol system using the HART protocol.

“Our clients often use the on-board temperature sensorfor freeze protection alarming,” says Meyer. “During thewinter months in cold climates, every process plant hassome type of freeze protection on various production lines.The protection can be electric heaters, steam, or just insu-lation to keep the process fluid from freezing.”

The conventional solution is to purchase and install atemperature sensor inside the freeze-protection housing.This can be very expensive and may not be cost-effectivefor many applications. “When our clients use the internaltemperature measurement already available over theHART interface, all that is required is a software changeto set alarm points,” adds Meyer. “One client in northernCanada with approximately 2,000 microprocessor-basedtransmitters estimates they have saved over $300,000 eachyear since 1989 using the ‘free temperature measurement’for alarming as compared to the previous installation with4-20 mA transmitters.”

Another use of the internal instrument temperature isfor ambient temperature error compensation on a dual-seallevel transmitter. The ambient temperature error of the dif-ferential pressure transmitter is virtually eliminated withfactory compensation using the internal temperature sen-sors. The problem is that the compensation is done beforethe dual seals are installed on a vessel, and this installa-tion can introduce temperature errors.

The temperature errors of the dual seals tend to offseteach other because the error on one side is canceled by asimilar error on the other side. But there still is one errorthat is not compensated: a shift in the output caused by atemperature-driven change in the density of the fluidinside the capillary between the two seals. As the ambi-ent capillary temperature changes, the change in the fluiddensity creates an error.

The low-cost solution is to take the on-board tempera-ture inside the basic differential pressure transmitter as agood approximation of the seal fill fluid temperature. Auser can then program a software compensation block witha table of the fill fluid density vs. temperature. A few basicmath calculations using the distance between the seals, thespan of the level measurement, and the density vs. temper-ature chart greatly enhance level measurement accuracy.

A hydrostatic tank gauging system can be configuredusing pressure transmitters with a temperature secondaryvariable. “We multi-drop two or three pressure transmit-ters, each with secondary temperature variables, to createa tank level measurement system. This system is marketedas our Hydrostatic Interface Unit,” says Jim Cobb, mar-keting manager for Austin, Texas-based Emerson Process

Management, formerly Fisher-Rosemount.Multivariable instruments often can use multiple vari-

ables to calculate process information. A differential pres-sure flowmeter, for example, uses pressure taps upstreamand downstream of an orifice plate, and the square root ofthe differential pressure is proportional to the flow. A mul-tivariable transmitter could transmit the flow value, theupstream pressure, and the downstream pressure. Calcu-lations performed at the instrument level can provide better accuracy and can off-load central controllers fromthese math-intensive tasks.

Valves Vie for AttentionThe multivariable features of HART are used extensivelyfor valve control. “The management of final control ele-ments through digital communication offers significantadvantages,” says James Gray, director of I/A systemsmarketing, Invensys Process Systems, Foxboro, Mass.“Intelligent valve positioners provide real-time feedbackof valve position, measurement of pneumatic supply pres-sure, and measurement of the positioner’s output signalto the actuator.” Operators can use the secondary variable

information to perform remote diagnostics on valves. HART valve positioners can monitor actuator pressure

(Figure 1). “Excess friction in a control valve often leadsto surging conditions that can result in dangerous processupsets,” says Bud Adler, director of professional devel-opment for Moore Industries, North Hills, Calif. “OurHART loop monitor can be configured to alarm on lossof actuator pressure (a secondary variable) that oftenresults from a clogged air filter or a torn diaphragm.”

Emergency shutdown valves can use the multivariable

“One client…saved over $300,000/year since 1989 using the ‘free temperature measurement’ for alarming.”

VI I

Figure 1: Bring Full Closure

A smart HART loop monitor used with a HART communicating

valve positioner provides a reliable and cost-effective alternative

for online emergency shutdown valve testing.

capabilities of a HART valve positioner. “Potentiallycatastrophic results can occur when an emergency shut-down valve does not close when triggered by a dangerousprocess upset,” Adler says. “These critical valves often gofor months or even years without being stroked to assureproper operation.”

Users do not stroke these valves because partial valveactuation without position monitoring can be hazardous.

“A prudent strategy is to upgrade the valve with a smartHART positioner and a HART loop monitor,” says Adler.“With this combination, the presence of adequate air sup-ply can be verified and the valve can be partially strokedon a regular basis to ensure its ability to move off of theseat.” The loop monitor reads the HART secondary vari-able and provides stem position feedback to ensure thatthe valve is only partially stroked.

“The management of final control elements through digital communication offers significant advantages.”

VI I I

Process Variable Values1

Primary Process Variable (analog)4-20 mA current signal continuouslytransmitted to host

Primary Process Variable (digital)Digital value in engineering units, IEEEfloating point, up to 24-bit resolution

Percent RangePrimary process variable expressed aspercent of calibrated range

Loop CurrentLoop current value in milliamps

Secondary Process Variable 1Digital value in engineering units available from multivariable devices



Commands From Host to Device

Set Primary Variable Units

Set Upper Range

Set Lower Range

Set Damping Value

Set Message

Set Tag

Set Date

Set Descriptor

Perform Loop TestForce loop current to specific value

Initiate Self TestStart device self test

Get More Status Available InformationCodes vary by manufacturer/device

Status and Diagnostic Alerts2

Device MalfunctionIndicates device self-diagnostic hasdetected a problem in device operation

Configuration ChangedIndicates device configuration has been changed

Cold StartIndicates device has gone through power cycle

More Status AvailableIndicates additional devices status data available

Primary Variable Analog Output FixedIndicates device in fixed current mode

Primary Variable Analog Output SaturatedIndicates 4-20 mA signal is saturated

Secondary Variable Out of LimitsIndicates secondary variable value out-side the sensor limits

Primary Variable Out of LimitsIndicates primary variable value outsidethe sensor limits

Device Identification

Instrument TagUser defined, up to eight characters3

DescriptorUser defined, up to 16 characters

Manufacturer Name (Code)Code established by HCF and set by manufacturer

Device Type and RevisionSet by manufacturer

Device Serial NumberSet by manufacturer

Sensor Serial NumberSet by manufacturer

Calibration Information for 4-20 mA Transmission of Primary Process Variable

DateDate of last calibration, set by user

Upper Range ValuePrimary variable value in engineeringunits for 20 mA point, set by user

Lower Range ValuePrimary variable value in engineeringunits for 4 mA point, set by user

Upper Sensor LimitSet by manufacturer

Lower Sensor LimitSet by manufacturer

Sensor Minimum SpanSet by manufacturer

PV DampingPrimary process variable damping factor, set by user

MessageScratch pad message area (32 characters), set by user

Loop Current Transfer FunctionRelationship between primary variable digital value and 4-20 mA current signal

Loop Current Alarm ActionLoop current action on device failure(upscale/downscale)

Write Protect StatusDevice write-protect indicator

1. Quality indicators for process variable data added with HART 6.

2. On/off values, eight bits, always defined as shown. Set by device self-diagnostics. Device status alerts increased to 16 bits with HART 6.

3. Additional tag with up to 32 international characters added with HART 6.

Data Items Available for Communication Between HART Devices and a Host

Keith Kleinschmidt

Keith Kleinschmidt

The inherent capability of HART valve positioners toprovide diagnostic and preventive maintenance informa-tion has proven invaluable in an installation at the Ayles-ford Newsprint manufacturing mill in Aylesford, England.The mill recently constructed a new de-inking and pump-ing plant and installed a modern newsprint machine.

The mill uses the Smart Adviser plant health monitorfrom Thermo Measurement, Winchester, England, toenhance the existing process monitoring and control sys-tem and to provide significant benefits in three areas:valve maintenance, valve failure, and multiplexing. “Alarge number of valve positioners with HART communi-cation are in operation at the mill,” reports Peter Vincent,sales and marketing director for Thermo Measurement.“Some are installed on minor applications but many per-form critical safety tasks.”

The advantage of using HART-capable devices is theirability to communicate digitally on top of the traditional4-20 mA line and transmit a wealth of data rather thanonly one process variable. Additional parameters that canbe monitored by a HART-capable valve positioner includerequested valve position, actual valve position, tempera-ture, and actuator pressure.

During normal operation, HART communication provides a cost-effective and time-saving method for iden-tifying problematic valves and valve positioners. Instru-ment performance is monitored by extrapolating the digitaldata readings related to the requested valve position andthe actual valve position and comparing the two readings(Figure 2).

The software analyzes valve positioner performanceand alarms when an abnormal condition occurs. “If thedifference between the two readings falls outside of thenormal tolerance of the valve (i.e. valve deviation), SmartAdviser logs it as a fault,” Vincent says. “The dead bandor hysteresis facility is used to determine the normal deltaand this is adjustable up to 25% of span to cover nearlyall conditions.”

In addition, should the valve deviation exceed the pro-grammed alarm point, the critical alarm mode providesinstantaneous indication of valve failure. When the main-tenance schedule is drawn up, the log is studied to seewhich valves are frequently working outside of normaltolerances. Smart Adviser can also function as a multiplexer,collecting up to 24 channels of field data from smart valvepositioners and sending it to the control system.

Available: Advanced DiagnosticsHART devices provide eight diagnostic status bits (16 bitswith the new HART 6 enhancement). These status bits canbe used to provide early warning of device problems.

Handheld communicators can access this informationwhen connected to the instrument loop, but most appli-cations would benefit from continuous monitoring ofthese status bits.

This monitoring function is provided with some DCSand HMI software packages, but not all control and mon-itoring systems have this functionality. “Moore Industries

provides loop monitors that are typically panel-mountedand connected just like a handheld calibrator. When aHART status bit changes, the loop monitor provides bothLED indication and a relay output,” says Adler.

The relay output can be connected to an existing con-trol and monitoring system, and the loop monitor can also

“This strategy provides differentiation between a sensor problem and potentially dangerous process condition.”

IX

Plenty of Devices

Device Category1 No. of Companies No. of Devices

Actuator 3 4

Analytical 12 58

Analyzer 1 8

Cabling 1 9

Calibrator 3 3

Control 4 6

DCS 2 2

Density 7 19

Flow 24 78

Gateway 1 1

Handheld 6 6

I/O system 9 23

Interconnect 1 9

Interface 9 9

IS barrier 6 44

IS isolator 1 6

Isolator 3 16

Level 31 60

Modem 6 8

Modem IC 1 2

Monitor 4 5

Positioner 18 28

Pressure 32 66

Services 5 15

Software 17 19

Temperature 26 41

Tools 5 15

Total 2382 560

1. per HART Communication Foundation web site

2. 111 different companies

provide a 4-20 mA signal based on one of the HART pro-cess variables. This allows a HART instrument to be inter-faced to a control system simply and quickly.

The performance of temperature transmitters can beimproved by using the status and diagnostic informationprovided by HART devices. “Most temperature transmit-ters incorporate sensor diagnostics to drive the 4-20 mAoutput either upscale or downscale upon sensor failure. Ina safety-critical application, this high or low action wouldoften trigger an expensive and perhaps unnecessary pro-cess shutdown,” says Adler.

HART compatible temperature transmitters can beused to avoid a process shutdown. “A HART loop mon-itor can be configured to use the status bits to provide arelay output indicating sensor failure,” Adler adds.“This strategy provides differentiation between a sen-sor problem and potentially dangerous process condi-tion. For more safety-critical applications, a dual non-voting scheme or a two-out-of-three scheme provideseven more reliability.”

A transmitter can lock at a fixed output value if it isplaced in a manual mode for tests and not returned to auto-matic operation. HART’s Primary Variable Analog Out-put Fixed status bit can be used to detect this conditionand alert an operator.

Distributed control systems such as Foxboro’s I/A canautomatically detect and use HART diagnostic informa-tion. “HART status and diagnostic signals can be transmit-ted in digital format and used by the control strategy andoperator displays,” says Gray. “In addition, there are morethan 30 diagnostic parameters available to maintenance todetermine the health of a valve. These are available throughour Technician’s Workbench I/A system module.”

Configuration Is Easy With a PCMost HART users are aware that HART instruments canbe configured remotely from any point on the HART datahighway. This can be performed with handheld calibra-tors or through a host computer.

Calibration performed with a host computer offersmany advantages over calibration via a handheld unit.“HART transmitters feature programming options that gofar beyond relatively common universal input capabili-ties. The arrival of simple and highly functional Windows-based calibration and configuration software allows fasterset up and more precise settings than is possible with ahandheld communicator,” observes Joseph Hage, vicepresident of engineering, Moore Industries.

Setup is simplified and time is saved by using a hostcomputer for calibration. “Handheld calibrators oftenrequire a user to scroll through lengthy configuration

branches,” Hage says. “Windows-based software allowssetup choices like input type and range, output zero and span, output damping, upscale/downscale drive, anddisplay parameters to be easily viewed, selected, anddownloaded to a HART instrument with a few clicks of a mouse.”

Configuration via a computer is especially advanta-geous for multiple instruments with the same parameters.

“Another significant advantage of the PC over a handheldis that once developed, a PC configuration can be storedto disk and downloaded to multiple transmitters. The moretransmitters with the same or similar setup, the more timeyou save,” concludes Hage.

Periodic instrument adjustment is a necessity for allprocesses, but continuous adjustment can be a require-ment for certain applications. These applications virtuallynecessitate a digital data interface to a smart instrument.If the composition of the fluid or gas that is being mea-sured changes continuously and if this change in com-position affects setup parameters, then continuous recon-figuration is required to maintain the accuracy of process measurements.

Smart instruments equipped with HART capability canenable continuous adjustment by receiving data frominstruments with respect to fluid or gas composition, usingthese data to automatically calculate settings, and down-loading these settings to the affected instruments.

Asset management software programs make extensiveuse of the device identification information availablethrough HART. This information is read by the asset management program and stored in a database, allowingthe program to automatically populate the database withpertinent information related to each instrument’s tag number, manufacturer, device type, final assembly num-ber, and serial number.

“There are more than 30 diagnostic parameters available to maintenance to determine the health of a valve.”

X

Accepted Delta/tolerance(dead band/hysteresis)

Valve becomessticky or not fully

positioned

Time

Delta between'requested' and 'actual'

valve position

Event is time anddate stamped and written to alarmlog, alarm is set

Figure 2: Requested vs. Actual

Valves can be monitored by comparing requested vs. actual

position data via HART.

XVI I I

s we saw in the article, “Call for Informa-tion,” processing companies are usingHART information in SCADA, assetmanagement, optimization, and ERP

systems. In the article, “Hidden in HART,” we saw themultitude of information available in field instruments, allof which is available for the taking. Here’s how to accessall that valuable information.

You will be happy to learn that not only is instrumentinformation readily available, it is downright easy to get.What’s more, you don’t have to be a programmer. We’llwalk you through the various options available, startingwith handheld terminals and working up to the most com-plex networking systems.

Calibrating Field DevicesVirtually everyone who owns HART instrumentationknows how to connect a handheld terminal to calibrate ordiagnose a field device. Essentially, you find any conve-nient location along the 4-20 mA signal line—betweenthe instrument and its termination in the control room orremote data acquisition system—and clamp on an adapter.The adapter is able to read the analog and embedded dig-ital signal without affecting the signal in any way.

Many of the handheld terminals are based on EmersonProcess Management’s 275 HART device, which it sup-plies to many HART vendors as a house brand. It wasdesigned years ago, but it still works just fine. Newerhandhelds from companies such as Smar are becomingavailable with Palm user interfaces. According to JonasBerge, manager of Smar Asia-Pacific Operations in Singapore, the Palm-based devices have a Windows-likeuser interface. “This comes in handy, as newer-generationHART devices have more diagnostics information thanever before,” says Berge. “Some information is bettervisualized graphically on a large screen than on just a text-based screen like the older units.”

About 80% of all process controller and field instru-ments have a HART interface these days, and practicallyevery maintenance technician, operator, instrument engi-neer and control engineer knows how to use a handheldHART terminal to change the zero and span, or check sta-tus. In probably 99% of the process installations, this waswhy HART devices were bought in the first place.

That was most definitely true 15 years ago, when

HART-based smart instruments first appeared on thescene. Back then, being able to work with a handheld ter-minal to remotely change, calibrate, and diagnose a fieldinstrument was all the rage. Today, engineers and techni-cians still use this capability out in the field, but now theydon’t have to. Instead of getting wet or huddling in aninstrument shed, engineers and operators can interrogateand change parameters from the comfort of the plant’scontrol room, using software loaded on any Windows-compatible PC. All they have to do is connect the PC tothe HART device network, and install a simple softwarepackage that emulates a handheld terminal.

Siemens and Emerson Process Management both offersoftware packages—Simatic PDM and AMS respec-tively—that run on a PC. Both can connect directly viaRS-232 to a HART multiplexer (see below), and provideall the configuration, setup, calibration, and diagnosticfunctions of handheld terminals.

At this point, Device Descriptions (DDs) enter the picture. While a handheld terminal or PC software pack-age has the ability to configure any HART device, DDsmake the procedure much simpler, because they providethe necessary parameter locations. Every vendor thatmakes a HART instrument also writes a DD that can beloaded into a handheld terminal. Typically, an end userloads handheld terminals with DDs for all the field instru-mentation in the plant so engineers and technicians canwork with anything.

Owners of the 275 HART terminals often send the unitoff to the manufacturer to have the necessary DDs loaded.This is much easier for some plants than loading DDslocally. Fortunately, the latest handheld terminals and PCsoftware packages are able to load from CD-ROMs, disks,or Internet sources, simplifying the update process. At pre-sent, there are more than 250 unique HART instrumentsfrom 70 vendors, all with individual DDs.

Getting Connected For a simple connection, a HART modem interface fromMACTek will connect your PC’s RS-232 port to aHART field device. The modem connects to the 4-20 mAsignal line just like the handheld communicators, andprovides an RS-232 signal containing all the digitalHART information.

If more than a few HART devices are involved, then

Take Advantage of HART Communications by Connecting Instruments to Control Systems, Laptop PCs, or Wireless Networks

Put It to Work

AA

RS-485 multiplexers from companies such as Arcom,Elcon, MTL, Pepperl+Fuchs, Stahl, or Thermo Measure-ment can be used (Figure 1). Up to 31 multiplexers can beconnected, each with 32 loops, for a maximum of 992devices. Some multiplexers support a multi-tier architec-ture that allows you to connect thousands of field devicesinto a single virtual network. The point is, no matter howmany HART devices you want to connect—from one tothousands—the connection to your PC is simple andstraightforward. All you need is a modem and a cable. Anda server, of course.

The HART Communication Foundation (HCF) recentlyannounced the availability of the HART to EnterpriseOPC server, or HART Server. Load this software into yourPC, hook up to HART devices with a modem, and yougain real-time access to all the process-related informa-

tion available in HART devices. With HART Server soft-ware and a $350 RS-232 link or a $2,000 multiplexer, you may have all the connective functionalityyou’ll ever need.

The HART Server is OLE for Process Control (OPC)-compliant, so it can obtain information from HART devicesand pass it along to any OPC client applications, such asSCADA/HMI software, an Internet web browser, an Excelspreadsheet, SQC and SPC software, and ERP systems. Forexample, real-time flow transfer data obtained from aHART device can be delivered to an Excel spreadsheet.

No special skill or customized software is needed.Using simple drop-down screens (Figure 2), fill-in-the-blanks functions, and tag names, the HART Server can beconfigured to automatically collect real-time informationfrom any number of HART devices and deliver it to anyOPC client application. Once configured, the HARTServer starts working immediately. Users can start gath-ering HART data in a matter of minutes, rather than sev-eral hours or days.

The HART Server is a plug-and-play device; that is, onceit is connected to the HART network via a modem, it auto-matically recognizes and communicates with all HARTdevices it can find on the network. This includes HARTdevices directly connected via RS-232 as well as devicesconnected through various control networks, multiplexers,and I/O systems. Once it establishes communication, theHART Server automatically retrieves device information.

Each OPC client that connects to the HART Server canrequest information at any rate desired. The client canspecify update frequency, dead band, and so on. TheHART Server will update information as requested andsend it to the client.

To see how easy it is to use, download a free evaluationversion of the HART Server. Just go to www.hartcomm.org, select the End User Info box, then click on HARTServer. From there, you can request a demo evaluation kitthat allows you to download server and related softwaremodules on your PC and simulate the complete serverfunctionality, free of charge for 30 days. This kit includes: HART Server software Xmtr-mv instrument simulation software (Windows

NT only) GnHost diagnostic software To use these modules, simply load the software into aWindows NT, 98, or 2000 environment, associate andjumper the correct COMM ports on your PC (for exam-ple, COMM 1 for the server, COMM 2 for Xmtr-mv) andfollow the instructions in the kit. You may also use yourown instruments in the simulation by connecting a HARTmodem to the serial port.

Hooking Up a HART MultiplexerIf you have more than one HART device, connecting themto your control system can be done in one of two ways.The first is to run the HART signals to a HART I/O boardin your control system.

The second way to obtain HART data is to use a HARTmultiplexer. This is ideal for end users with control sys-tems that do not yet support HART digital data for con-trol and monitoring purposes. Users with legacy controlsystems also are in this situation.

David Hohenstein, manager of the hardware marketinggroup at Pepperl+Fuchs, Twinsburg, Ohio, explains thathooking up a HART multiplexer is easy. “Just run the 4-20 mA signals from HART field devices into a HARTmultiplexer,” explains Hohenstein. “The multiplexer stripsoff the digital HART data, then sends the 4-20 mA signalon its way.”

The original 4-20 mA signal is unaffected, so it can con-nect to a normal analog input board at a control system.

The HART Server starts working immediately. Users can start gathering HART data in a matter of minutes.

XIX

Figure 1: Serial Killers

Multiplexers can be used to bring a virtually unlimited number

of HART field devices into serial ports.

Meanwhile, the multiplexer sends the digital HART datato the control system via a serial link, typically RS-232 or RS-485.

The only trick to using a HART multiplexer is that itmust be compatible with the control system, saysHohenstein. “The connection to all HART instrumentsis standard, but every control system is different. Youhave to purchase a HART multiplexer with an I/O inter-face that works with your particular control system.” Pep-perl+Fuchs has 40 different HART multiplexers, withmodels ranging from 32 to 255 channels.

Once connected to the control system, the multiplexerbecomes a passive device, serving merely as a conduit ofinformation. When asset management or HART Serversoftware in the control system wants data from a HARTinstrument, it sends the device a HART command. Thecommand signal goes to the HART multiplexer whichembeds the digital signal into the 4-20 mA loop. The com-mand arrives at the HART device where it is acted upon.The HART device embeds the requested information intothe 4-20 mA signal, and the multiplexer strips out the dig-ital data and sends it on to the control system.

Issues to be considered with HART multiplexers pri-marily involve speed. A multiplexer with 255 channelsand a single modem operates much slower (on a channel-by-channel basis) than does a 32-channel multiplexer withone modem. If a control system needs faster access to data,it can use smaller, eight or 16-channel multiplexers, oryou can purchase multiplexers with multiple modems.

Getting More ComplexSo far, we’ve only looked at HART networks that connectto a single PC. Much more capability is available for aserious user. It’s possible to connect your HART instru-ments into most major networks, the Internet, and eveninto wireless systems.

Arcom, for example, sells a series of multiplexers thatplug into Modbus networks. At Shell’s Tejas Calumet gasplant in Louisiana, data from Rosemount HART flowme-ters is stored in Modbus registers in an Arcom HtNodemultiplexer, allowing any Modbus host to access theinformation. A SCADA system in a PC accesses the flowdata every five minutes by interrogating the HtNodedevice over Modbus.

HART multiplexers are available that support EthernetTCP/IP connections. Such a system could easily connectinto the Internet, a plant intranet, OPC systems, or otherplant network schemes based on Ethernet. In such a case,a PC or workstation equipped with HART Server softwarecan access HART instruments anywhere on the network.With a HART Server in your PC, you can make instru-

ment information available to any OPC client device (Figure 3). This includes web browsers, SCADA systems,ERP systems, and software that drives cell phones, hand-held computers, personal digital assistants (PDAs), andwireless equipment.

A control system designed and installed by SysIncEngineering to support multiple plants, process areas, andloading facilities makes extensive use of HART devices.A Windows 2000 HART OPC Server at each plant is con-nected directly to an Arcom 32-channel HART multi-plexer via an RS-485 serial port.

Approximately 70 two-wire and four-wire HARTdevices per plant are connected to the multiplexer. Thesedevices include SAAB and Krohne radar level gauges, Inor

and Smar temperature transmitters, Micro Motion massflowmeters, and Endress+Hauser volumetric flowmeters.

Most of the HART devices are wired in a multi-dropconfiguration and connected to the HART OPC Server.Other HART devices feed into four-channel ProLinxHART/Modbus gateways that in turn feed into the Modbus OPC server. The OPC server provides a cleaninterface to custom as well as off-the-shelf SQL andweb-based applications.

Most of the devices are set up on multi-drop networksand do not use the 4-20 mA signal available from eachdevice. The faster update time of a 4-20 mA signal tooka back seat to the accuracy of the HART digital signal forthis application.

According to the system integrator, the client plans totake advantage of many HART features. “Our client willuse the multivariable, status and diagnostics, and remotecalibration capabilities of the HART devices. The most crit-ical capabilities for this application are multivariable anddevice status,” says Curtis Butt, electrical engineer, SysInc.“The long-term manageability of the system required us to

“The multiplexer strips off the digital HART data, then sends the 4-20 mA signal on its way.”

XX

Figure 2: Drop-Dead Easy

The HART Enterprise OPC server offers drop-down screens,

fill-in-the-blanks functions, and tag names.

provide not only remote access to basic variables, but alsoremote diagnostics and configuration.”

The client and SysInc expect to see a significantimprovement in the reliability of the data coming fromthe devices. “The old system had only local displays ateach instrument,” says Butt. “Operators did not trust thesystem and would often revert to manual operation. Partof this was due to devices being in remote locations,which led to difficulties in calibration and verification ofproper operation.”

Operators will now be able to remotely access devicesand receive accurate information. “The new system willprovide complete access to all devices including status,calibration, and configuration information,” Butt con-cludes. “Use of the HART protocol will help us achievebetter repeatability and higher accuracy, both in the pro-cess area and in the bulk storage/inventory area.”

You may never need such complex communicationschemes, but it is comforting to know that HART instru-ments fit right in.

Connecting to ControlsHART devices can connect directly to control systems anddevices, allowing users to make use of instrument data formonitoring, alarming and control purposes.

Allen-Bradley, Wickliffe, Ohio, provides a HARTinterface module for its PLC 5 and SLC programmablecontrollers that allows a PLC to see HART data. Installedas a remote I/O device, the module acquires data from aHART instrument, strips out the HART signals, and putsthe data into a format that can be addressed by ladderlogic programming.

Pat Moyer, product manager at A-B, explains that thesystem is supplied with preconfigured instructions thatsupport HART commands. “We provide several basicHART commands, but a user is free to write additionalcommands in ladder logic to perform whatever functionsare needed, such as data logging, alarm checking, or mon-itoring device status.” Moyer says the HART module is abig hit among certain A-B customers. “We have users inthe food and oil and gas industries that use the moduleextensively,” she says.

Yokogawa Corp. of America, Newnan, Ga., offers hard-ware and software that acquire HART data and make itavailable to its Centum control systems. Bruce Jensen,manager of systems marketing, explains that a Centumcan acquire data from a standard HART multiplexer orfrom its own FIO 4-20 mA input modules. “The FIOdevices have a HART module that extracts the digitalHART data from the 4-20 mA signal and provides bothanalog and digital data.” FIO devices are available in eightor 16-channel versions.

Yokogawa’s Plant Resource Management software for-mats the HART data and makes it available to the HMI andcontrols software, where it can be monitored, trended,logged, and displayed. Jensen says most customers use thecapability to automate instrument maintenance functionsbecause the software supports all the standard configura-tion and calibration functions from an HMI screen.

“We have several users, mostly in the pharmaceuticalindustry, who are starting to take advantage of HART datafor more sophisticated purposes,” says Jensen, “but mostof our users are not familiar with all the capability avail-able within HART.”

Virtually all major process control companies supportHART, so it should be relatively easy to connect your con-trol system to your own HART devices.

Dave Sheppard, vice president of I/A Systems atFoxboro/Invensys, Foxboro, Mass., says Foxboro has sup-ported HART for maintenance purposes for years. “Wesupport the connection of HART multiplexers from sev-eral suppliers,” he explains, “and we bring the HART datainto a dedicated PC where third-party software can obtaindata for maintenance calibration and equipment configu-ration functions.”

At ISA/2001 in Houston, Foxboro will unveil a neweight-channel analog I/O board with a HART module thatsplits out the digital signal and feeds it into standard equip-ment control block (ECB) modules. “The HART data willbe made available to Foxboro’s HMI and process controlsoftware like any other process variable, so it can be usedfor control, data logging, monitoring and so on,” saysSheppard. “We are taking orders now for delivery in the

“The HART protocol will help us achieve better repeatability and higher accuracy.”

XXI

Figure 3: Opened to OPC

The HART Server can make process data available to any

OPC-compliant device: web browser, SCADA system, ERP

system, cell phone, PDA, wireless, etc.

second quarter of 2002.”Honeywell, Phoenix, is on a similar track. “We offer

standard HART multiplexers from Pepperl+Fuchs orMTL,” says Joe Serafin, product manager for PlantscapeI/O. “The MUX connects to the serial port of a PC, whichruns Cornerstone or some other third-party HART soft-ware for maintenance and instrument calibration.”

Honeywell’s customers have been asking for additionalHART capabilities, so Honeywell has a HART I/O cardin the works, scheduled for introduction in the near future.“The new card will strip off the HART digital data fromthe 4-20 mA signal and make it available to the controlenvironment,” says Serafin.

Meanwhile, if you don’t want to wait for products tobecome available, you can take matters into your ownhands and implement a system using the HART Server.

By the NumbersHere’s a step-by-step procedure for getting started withthe HART Server. This should get you up and running ina matter of just a few minutes:1. Load and install the HART Server software on your PC.

You can download it from the Internet or load it froma CD-ROM.

2. Configure your PC’s COM port to communicate withthe HART network. You need to tell the PC port if itwill be seeing RS-232, RS-485, or RS-485 with an Eth-ernet adapter. The HART Server configuration screenshelp you do this.

3. Configure the HART Server to set up links between thedata sources and the data users (what programs want tosee what data?). Again, the HART Server configurationscreens ask the right questions.

4. Verify and test the HART Server using the GnHost diag-nostic software tool, supplied by the HART Foundation. Most of the configuration menu screens are similar to

Windows Explorer. With a series of mouse clicks, youshould be able to complete the configuration quickly. TheHART Server will automatically detect and learn the HARTdevices connected to the port. At the end of the configura-tion process, two-way communication between the HARTServer and the HART instruments will be fully established.

The HART Server pass-through software lets OPCclient applications send HART commands to HARTinstruments. Therefore, any software such as configura-tion or valve analysis packages that run on handheld ter-minals can run on a PC equipped with HART Server.

Likewise, HMI and SCADA software can access datausing standard OPC functions. The OPC client browsesthe data items available from the server and subscribes tothe data items of interest. This is a standard OPC function

that is supported by all software packages that claim to beOPC clients or servers, such as HMI/SCADA systems.

When you get the HART system connected to theHART Server, simply go to the part of your HMI orSCADA system that defines I/O points. You will beadding the HART instruments the same way you config-ured your plant when you first installed the HMI/SCADAsystem: that is, you’ll probably use a menu-based config-uration screen to define the path, device, tag name, and soon, and your HMI/SCADA system will lead you throughthe process.

You will also be able to define how often you want eachparameter or groups of parameters updated, or “turned on.”When a group is turned on, the HART Server will publishthe data items (i.e., update, acquire, and send the group tothe client). This allows processing packages from loop con-trollers to process historians to obtain instrument informa-tion from the field as often as necessary, simply by makingthe appropriate definitions in an OPC software package.

Using Specialty DevicesSeveral HART instrument vendors have developed spe-cialty processors and loop monitors that perform uniquediagnostic and analysis functions. In many cases, thisallows you to take advantage of the information containedin your HART instruments without making a network con-nection or using PC software. In other words, you cansolve local problems without involving the plant’s maincontrol system.

An annoying problem in many plants involves stickingvalves and worn-out positioners. Such problems are usu-ally difficult to detect for most control engineers, mainte-nance technicians, and even the best process control andSCADA systems. Most all these entities are usually at a loss

“HART data will be available like any other process variable, so it can be used for control, data logging, and monitoring.”

XXI I

Figure 4: Dig Out All the Data

Loop monitors can read all the data from HART field devices

and convert it into additional signals for control systems.

to explain a valve’s bad behavior when it starts hunting,sticking, and performing poorly. The answer in mostplants is to pull the valve out of the line for maintenance.

A HART-based smart valve positioner has all the infor-mation you need to analyze valve performance. HARTdata can tell how many times the valve opens and closes,how much the stem has traveled, if actuator pressure haschanged, and a host of other variables that are availablethrough HART, but are never monitored in most plants.The positioner itself can perform its own analyses. Forexample, the Smar FY301 performs diagnostics, collectsoperational statistics, and stores information pertinent tothe management of the valve and actuator.

But how do you get to this data, and what do you dowith it? You can install a HART loop monitor to moni-tor any of these variables, and to sound an alarm if it seesa condition that could result in dangerous process upsets.For example, excess friction in a valve can lead to surg-ing conditions. Loss of actuator pressure from a cloggedair filter or torn diaphragm can cause a dangerous orcostly control offset. A loop monitor can be set to alarmon any of these conditions.

Aylesford Newsprint in Aylesford, England, has manyHART-based smart valve positioners and it uses SmartAdviser from Thermo Measurement to check for faultsand problems. The module accepts data from up to 24valve positioners, performs a variety of calculations tocompare the requested position to the actual position,compares it against a deadband, monitors pressure to thepneumatic actuator, and sounds an alarm if it detects afault. The module can also act as a HART multiplexer;that is, it can collect data from the valve positioners andsend it to a PC via an RS-232 link.

Control systems that are not fitted with a HARTmodem and HART Server cannot obtain any data otherthan the 4-20 mA signal from HART instruments. Here,loop monitors can serve as an intermediary. For exam-ple, Moore Industries’ SPA monitor can read all thedata from a HART device, extract digital data, and pro-duce additional signals (Figure 4). It provides up to fourindependent relay outputs that can be used as alarmswhen process conditions fall outside of user-selectedhigh or low limits. It can also pick off any of the fourdynamic (analog) variables from the HART data andtransmit it to the control system as a 4-20 mA signal.For example, it could take the density value from aCoriolis flowmeter, the stem position for a valve, or itcan calculate an analog variable as a function of two ormore other variables.

Rosemount’s Tri-Loop monitor, for example, canextract the remaining three process measurements and

create three additional 4-20 mA analog signals from asingle HART message. The HART 4-20 mA signal goesto a control system flanked by three additional 4-20 mAsignals. This makes it possible to extract gross flow, netflow, mass flow, and process temperature from a BrooksInstruments TRi-20 flowmeter; or valve position, actua-tor pressure, controller process variable, and controllersetpoint from Fisher, Masoneilan, Neles, Samson,Flowserve, and other valve actuators.

Multivariable devices such as these are becoming avail-able to solve specific problems and help maintenance andoperations engineers obtain the most information possiblefrom their HART devices.

The best part is that all this diagnostic, status, and oper-ations information has been available all this time, so itrequires no additional investment by end users. All theyhave to do is go get it with handheld devices, multivari-able loop monitors, or PCs and HART Servers.

HART Marches OnAlthough HART has been available for 15 years, like Eth-ernet it is showing no signs of getting old. The current ver-sion is HART 5, but HART 6 has recently been approvedby the foundation’s members.

“HART 6 is an augmentation of the existing standardthat allows the installed base to continue while incorpo-rating new features,” says Ben Cianfrone, engineeringdevelopment manager, Fluke Corp., Everett, Wash. “Wewill be able to use this for at least 10 or 15 more years,or even longer.”

The upgrade was necessary because HART instru-ments are getting smarter all the time, incorporatingmore self-diagnostics, saving more operational historydata, and reporting on the quality of the data they obtain.Someday, HART devices may even have other HARTdevices embedded within, such as flow computers andmulti-channel temperature monitors. HART 6 makes allthis possible, without making any previous HARTinstruments obsolete.

Some of the new functions include Extended Device Status, which alerts users to situations such as, “deviceneeds maintenance;” Device Variable Status, whichallows field devices to self-validate and provide qualityindicators on process data (good, poor, bad, fixed); LongTags, which allows international characters and longertag names; Configuration Change Counter, which deter-mines if a field device configuration has been changed;and Block Data Transfer, which moves large blocks ofdata between masters and field devices. The new specshould be available for all to review at the ISA Show in September.

“We will be able to use [HART 6] for at least 10 or 15 more years, or even longer.”

XXI I I

XXVI

he preceeding articles have shown how HARTis much more than just a way to calibrateflowmeters. It provides an enormous amount ofplant-floor information not obtainable through

any other means, and you don’t need a complicated field-bus system to get to that data. In fact, since most of yourinstruments, valves, and controllers already have a HARTinterface, obtaining real-time process information is notonly easy, it is very inexpensive. All you need to do islearn how to use it.

When it comes to calibration and diagnostics with hand-held terminals, HART technology is so easy to learn thatvendors often teach their customers over the telephone.Bud Adler, director of professional development at MooreIndustries, North Hills, Calif., says he often walks peoplethrough a quick course. “It is fairly easy to lead someonethrough a procedure over the phone,” says Adler. “Thetechnology is simple and the procedures are straightfor-ward. We do it all the time.”

Jon Tandy, sales engineer at Arcom Control Systems,Kansas City, Mo., agrees. “I’m the one who usually deals with HART customers from sales through tech support, and I generally educate them over the phone,” heexplains. “Often, they have some basic understanding of HART already.”

When you need to go beyond handheld terminals, it getsa bit more difficult. Moore Industries’ Adler travels aroundthe country giving HART seminars at trade shows and“Lunch-and-Learn” sessions, where employees from achemical or process plant get a sandwich and a seminar onHART. “We get everyone from instrument engineers tomaintenance technicians,” says Adler, “and most areamazed to find out what the instruments already installedin their plant are capable of providing.”

Some companies conduct on-site training during instal-lation. Thermo Measurement’s signal conditioning product manager, for example, trained people at Ayles-ford Newsprint on-site.

All this vendor activity is useful and helpful, but whatthe industry really needs is a better and more consistentway to teach end users about HART.

Regarding Users in a New LightThe HART Communication Foundation (HCF) has beenstrictly a vendor group since its founding in 1993. During

that time, HCF left all the end user promotion to the mar-ketplace while it concentrated on helping the vendorsdesign and develop new instruments, software, interfaces,calibrators, and similar devices. All of HCF’s educationalefforts and training classes have been designed for ven-dors, and all of its efforts toward standardization havebeen aimed at solidifying and enhancing HART products.

It’s accomplished that, in spades. Today, HCF hasmore than 130 vendor members all over the world thatoffer a large number and variety of HART-compliantproducts (Figure 1). Virtually every process instrumentbuilt today has a HART interface. In spite of all the pub-licity garnered by the various fieldbuses, the fact remainsthat HART has the largest installed base in the industry,and it is growing every day. This is in part because many

fieldbus-compatible instruments and devices also have aHART interface. Fieldbus users may discover they actuallyhave two plant networks built into their devices: fieldbusand HART.

The HCF realizes its future lies in educating, enlight-ening, and engaging users, so it has launched an End User Program. This program will teach users about thebenefits of HART, establish a training curriculum, bringend users into the HCF, and involve them in the HARTinterface for everyone’s benefit.

Educational SupportLearning more about networking and HART Servers is alittle bit beyond a five-minute phone call from the rep.You need training and non-vendor technical literature.

The HART Foundation Will Help You Extract Information From Your Field Instrumentation

Get Started

TT

North America46% (65)

Europe44% (62)

Asia9.3% (14)

Australia0.7% (1)

Total companies: 142

Figure 1: A Global Standard

There are HART Communication Foundation member companies

almost everywhere you’d want to go.

HCF understands. Here’s what they have in store for you: The Complete HART Guide on CD-ROM: This is an

excellent way to learn how HART works, in a formatthat is easy to pass on to fellow workers and bosses.The CD-ROM was recently completely revised toinclude new topics such as HART 6, asset management,and the HART Server. The new CD-ROM is availablefor free from HCF, and you should be able to get a copyat the HART Foundation booth at the ISA or Interkamashows this year. To obtain a free copy via the Internet,go to the HCF web site (see next bullet). You can alsocall the HCF office in Austin, Texas.

Web site: The HCF web site at www.hartcomm.org hasbeen completely updated to include a new end user focuson applications, education, downloads, Q/A forums, anda newsletter. An end user can pick up a large amount oftechnical, product, and application information by simplybrowsing through the web site and following the links.

End user training: The HCF plans to offer a comprehen-sive two-day HART technology education class, start-ing in 2002. Two pilot classes will be held in 2001. Theclasses will be taught by HCF staff and will cover thetechnology, using DDs, applications, device configura-tions, communications, and using the HART Server.

To find out more about specific dates and times, con-tact HCF or visit the web site.

After HCF runs the pilot classes, it plans to finalizethe training materials so that users will be able to con-duct classes themselves. This will put training out inthe field, closer to end users.

Coming on BoardThe HCF also realizes that end users will determine thefuture of HART. Already, many experienced users areasking for additional capability and functions. AlthoughHART has been available for 10 years for field commu-nications, it is just now entering the early adopter step inits lifecycle as a networking system. At this point inHART development, user input is critical.

The HART Foundation is considering forming an enduser core group to provide it with input on key issues suchas HCF activities, technology issues, applications, prod-uct needs, and other ideas. If you are interested in partici-pating, contact HCF.

While fieldbus efforts are struggling to deal with alarge number of unrelated and incompatible networks,HART offers an excellent alternative. The HCF and itsvendor members have built a technology that works, butend users are needed now to make sure that HART con-tinues to meet all the information and network needs ofthe process industry.

The HCF realizes its future lies in educating, enlightening, and engaging users, so it has launched an End User Program.

XXVI I

HART Communication Foundation

The HART Communication Foundation (HCF) is an independent,

non-profit organization that provides worldwide support for the

HART protocol. Established in 1993, HCF is the technology owner

and standards-setting body for the HART protocol. HCF manages

the protocol standards, ensures the technology is openly avail-

able for the benefit of the industry, and educates users by pro-

viding training and support for application of the HART protocol.

HART Workshops

Workshops are an excellent value since an engineer can often

spend weeks of valuable development time overcoming the learn-

ing curve of the protocol. A workshop provides all the needed

information in a two or three-day session. Workshops include:

HART End User Workshops: During the latter part of 2001,

the HCF will begin training courses for end users.

HART Fundamentals Workshop: The HART protocol is

relatively easy to implement, but can have a steep learning

curve. This provides all the information and tools to efficiently

develop a HART-based device.

Writing Device Descriptions (DDs) Workshop: The Device

Description Language (DDL) provides significant benefits to slave

developers, end users, and host manufacturers. This workshop

explains how to use DDL to write DDs for a product. Participants

leave the workshop with a prototype DD for a HART device.

Memberships

HART Communication Foundation memberships are open to sup-

pliers, system integrators, end users, and others interested in the

use of the HART protocol. Regular/associate and sponsor mem-

berships are structured for corporate members. Information-only

memberships are available for non-profit educational institutions,

research institutes, and government agencies. End user compa-

nies can join as a regular/associate member, and individual con-

trol engineers may join as information-only members.

Members are able to attend foundation meetings; participate

on committees; obtain free specification updates; get 100 free

copies of the quarterly newsletter; access engineering support

services; and receive discounts on workshops, development tools,

protocol licenses, and device description registrations.

A membership application form is available on the web site.

Contact Information

HART Communication Foundation

9390 Research Blvd., Suite I-350

Austin, TX 78759

Tel: 512/794-0369; Fax: 512/794-3904

Web site: www.hartcomm.org

E-mail: [email protected]

F O R T H E P R O C E S S I N D U S T R I E S

A N A D V E R T I S I N G S U P P L E M E N T T O S E P T E M B E R / 2 0 0 7

WirelessHART™

InfoRmATIonUncHAIned!

The new interoperable wireless communication standard for

the process industries

CTHart07_01_Cvr.indd 4 8/20/07 3:11:06 PM

97251_HARTware_370x271_e 23.08.2004 15:19 Uhr Seite 1

Probedruck

C M Y CM MY CY CMY K

Discover the wide selection of HART-compatible process instruments – reliable, robust, and featuringthe advanced SIMATIC® PDM process device manager. Using the SIMATIC PDM, we integrate HART-compatibleproducts into our SIMATIC control topology. What’s more, this software also operates with HART-compatible devicesof other manufacturers. That means that you can now use HART to configure, parameterize, and maintainmultivendor devices – via PROFIBUS PA, PROFIBUS DP, and other industrial buses. Best of all, HART is an integralpart of the SIMATIC PCS 7 automation platform, giving you a direct link to Totally Integrated Automation. For moreHART facts on best solutions for the process industry, please have a look at our homepage.

www.siemens.com/processautomation

SIMATIC

PDM

SIMATIC

PDM

PU

BL

ICIS

E2

00

01

-F2

0-P

71

0-V

2-7

60

0

Introducing the best HARTwarefor the process industry

CTHart_FPA.indd 2 8/20/07 4:48:11 PM

97251_HARTware_370x271_e 23.08.2004 15:19 Uhr Seite 1

Probedruck

C M Y CM MY CY CMY K

Discover the wide selection of HART-compatible process instruments – reliable, robust, and featuringthe advanced SIMATIC® PDM process device manager. Using the SIMATIC PDM, we integrate HART-compatibleproducts into our SIMATIC control topology. What’s more, this software also operates with HART-compatible devicesof other manufacturers. That means that you can now use HART to configure, parameterize, and maintainmultivendor devices – via PROFIBUS PA, PROFIBUS DP, and other industrial buses. Best of all, HART is an integralpart of the SIMATIC PCS 7 automation platform, giving you a direct link to Totally Integrated Automation. For moreHART facts on best solutions for the process industry, please have a look at our homepage.

www.siemens.com/processautomation

SIMATIC

PDM

SIMATIC

PDM

PU

BL

ICIS

E2

00

01

-F2

0-P

71

0-V

2-7

60

0

Introducing the best HARTwarefor the process industry


4-20mA Representing the Primary Variable (Mass Flow)

HIM Smart HARTLoop Monitor

"Breaks Out" Data from Smart HART Instruments

4-20mA Proportional to 2nd Variable (DP)

4-20mA Proportional to 3rd Variable (P)

4-20mA Proportional to 4th Variable (T)

HART Transmitter Diagnostics Fault Alarmor Additional Process Alarm

Control System

Smart HART MultivariableMass Flow Transmitter

Flow

High Alarm in Response to 4th Variable (T)

HART Digital Signal Carrying Primary, Second, Third,Fourth Variable Process Data,and InstrumentDiagnostic Information

HART Communicator

can be connected anywhere along the 4-20mA loop

Unlock Your Smart HART® MultivariableTransmitter’s Hidden Secrets

The full potential of yoursmart transmitter has beenlocked up way too long. Setit free with our HIM SmartHART Loop Interfaceand Monitor.

Converts HART to 4-20mAThe HIM converts HARTdigital data to 4-20mAsignals that your DCS orPLC control system canhandle. A multivariablemass flow transmitter, forexample, measures threevariables: differential

pressure or raw flow, pressure, and temperature. Fromthese non-primary measurements, it calculates mass

flow, and sends this on 4-20mA wires back to yourcontrol system. The problem is, the non-primarymeasurements, and the valuable data they provide,never make it out of the field. The solution is theHIM. It “breaks out” non-primary measurements,and sends them as 4-20mA signals to your controlsystem.

Take Full Advantage of In-Place“Legacy” Smart HART Transmitters.The HIM is your key to leaving trusted(and paid for) smart transmitters inplace, yet still take advantage of all theprocess and diagnostic information theyhave to offer.

HART is a registered trademark of the HART Communication Foundation.

CONTROL HIM Ad 8-05.pmd 8/15/2005, 9:27 AM1


Expanding the PossibilitiesBy Ron Helson, Executive Director, HART Communication Foundation

As the technology owner and standards-setting body for the HART Protocol, the HART Communication Foundation was in a

unique position to develop a wireless communication standard for process measurement and control applica-tions. We were able to draw on the technical resources and expertise of more than 200 member companies to create a new technology that expands the capabilities of the HART Protocol while protecting the global installed base of 24+ million HART devices.

WirelessHART™ Communication is a new capability de ned in the HART 7 speci cations that establishes the rst open and interoperable wireless communication standard for the process automation industry. WirelessHART™ focuses on the needs of the industry by providing a simple, reliable, and secure technology for wireless transmission of process and diagnostic data from intelligent eld devices.

This new wireless standard builds on established and eld-proven technologies, including the HART protocol, IEEE 802.15.4 radios, frequency-hopping, and mesh networking. These standards allowed us to create a solution that is easily deployed by instrumentation pro-fessionals—preserving the HART-enabled devices, tools, training, and work procedures used today.

WirelessHART™ is fully backward-compatible with existing instrumentation, extending the value of installed HART-enabled devices. It complements, but does not replace, wired HART technology, providing an additional

capability that can bene t both your existing wired ap-plications and new monitoring and control applications.

Why wireless? Wireless provides a cost-effective ad-ditional communication path for many legacy control systems, enabling access to the intelligent information in eld devices. And new measurement and control devices can be quickly and easily deployed without the physical limitation and expense of signal wire.

Soon suppliers will introduce HART 7-enabled devices that will provide a new way to monitor, manage, and diagnose existing and new measurement and control instrumentation—allowing your intel-ligent eld instruments to communicate valuable information to provide signi cant operational cost reductions, enable process improvements, and facilitate regulatory compliance.

HART Communication is stronger than ever. Mil-lions of HART-enabled devices are purchased and installed each year. The HART protocol continues to be the technology of choice for smart instrumenta-tion. WirelessHART™ is yet another example of how the Foundation continues to strengthen and enhance the technology to ensure that it supports your needs and protects your investment.

The following articles provide an overview of the new enhancements to the HART Protocol standard. You will learn what WirelessHART™ is, where it can be used, how it expands the bene ts of HART technology, and what you need to know to start expanding the possibilities!


HART CONTENTS/INDEX

Expanding the Possibilities

For more information on WirelessHART™, go to www.controlglobal.com/articles/2007/184.html.

HART® and WirelessHART™ are trademarks of the HART Communication Foundation.

ADVERTISERSABB Instrumentation . . . . . . . . . . . . . . . . . .27Emerson Process Mgt/Plantweb. . . . . . 14, 15Hart Communication Foundation . . . . . . . .28Honeywell Field Solutions . . . . . . . . . . . . . .16MACTek . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Moore Industries . . . . . . . . . . . . . . . . . . . . . .4ProComSol. . . . . . . . . . . . . . . . . . . . . . . . . .26Siemens AG . . . . . . . . . . . . . . . . . . . . . . . .2, 3Invensys/Foxboro. . . . . . . . . . . . . . . . . . . . .19Turck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Yokogawa . . . . . . . . . . . . . . . . . . . . . . . . . .6, 7

8Wireless HART™— Information Unchained

WirelessHART™ releases the informa-

tion trapped in your eld devices by

offering 100% backward-compatibility

with your installed HART devices.

12 What Wireless HART™

Can Do For YouWhen facing new operational chal-lenges, innovative companies nd solutions using wireless technologies.

24 How to Get Unchained with Wireless HART™

WirelessHART™ offers several ad-vantages over other wireless alterna-tives. Here’s how to get started.

CT0709_Hart.indd 5 8/23/07 10:51:17 AM

Asset Excellence Performance+Availability+= + PredictabilityReliability

Versatile Device Management

Reliability + Maintainability = Availability

Hear the pulse of your plant Diagnose with the most, one tool for all.

For more information and free trial software, visit promo.us.yokogawa.com and enter key code AD9710.

The Yokogawa FieldMate Versatile Device Management System is a new PC-based integrated software tool that handles parameter setting for intelligent field devices, regardless of their make or field communication protocol. FieldMate speeds up device configuration and problem solving, and automatically stores a work log for a traceable field maintenance database that consolidates the maintenance work flow and facilitates the sharing of maintenance know-how.

EDDL™

. . . where people are watchful and attentivewhile your business responds to change quickly and efficiently.

Now picture an operation thatdelivers non-stop production while confidently

expanding your capabilities into the future.Imagine no further. This is the vision and

promise behind VigilantPlant,the clear path to operational excellence.

Envision a plant . . .

Yokogawa Corporation of America800-447-9656www.yokogawa.com/us

Yokogawa Corporation of America800-447-9656 www.yokogawa.com/us

800 524 SERV7 3 7 8

AD9710 8/14/07 10:29 AM Page 1


Asset Excellence Performance+Availability+= + PredictabilityReliability

Versatile Device Management

Reliability + Maintainability = Availability

Hear the pulse of your plant Diagnose with the most, one tool for all.

For more information and free trial software, visit promo.us.yokogawa.com and enter key code AD9710.

The Yokogawa FieldMate Versatile Device Management System is a new PC-based integrated software tool that handles parameter setting for intelligent field devices, regardless of their make or field communication protocol. FieldMate speeds up device configuration and problem solving, and automatically stores a work log for a traceable field maintenance database that consolidates the maintenance work flow and facilitates the sharing of maintenance know-how.

EDDL™

. . . where people are watchful and attentivewhile your business responds to change quickly and efficiently.

Now picture an operation thatdelivers non-stop production while confidently

expanding your capabilities into the future.Imagine no further. This is the vision and

promise behind VigilantPlant,the clear path to operational excellence.

Envision a plant . . .

Yokogawa Corporation of America800-447-9656www.yokogawa.com/us

Yokogawa Corporation of America800-447-9656 www.yokogawa.com/us

800 524 SERV7 3 7 8

AD9710 8/14/07 10:29 AM Page 1


S- Advertising supplement to CONTROL

Of the 24 million-plus HART-enabled de-vices currently installed around the globe, only about 10 percent are delivering their

full diagnostic potential, a state of affairs that is poised for change,” says Ron Helson, HART Communication Foundation (HCF) Executive Director. “Development of the WirelessHART,™ standard, along with the new enhanced DDL capabilities, opens the door to the untapped func-tions in HART devices and simplifies the task of integrating instrumentation from multiple vendors into plant asset optimization systems.”

Enhancing haRTSince 1990, millions of HART devices have been installed, and most remain in service today. Pro-tecting that installed base was paramount when the HART Foundation, with the assistance of end users and ABB, Adaptive Instruments, Coronis, Dust Networks, Elpro, Emerson Process Manage-ment, Endress+Hauser, Flowserve, Honeywell, MACTek, Omnex, Pepperl+Fuchs, Phoenix Con-tact, Siemens, Smar, and Yokogawa, defined the requirements for WirelessHART.™

Emerson Process Management’s director of HART and Fieldbus Technology, Marty Zielinski, says, “The WirelessHART™ standard effort has produced a fully digital protocol that uses consolidated mechanisms to reduce communications overhead and adds im-portant capabilities to the HART standard, including alarms, alerts, status with measurements, and time synchronization, just to name a few.”

The results are seen in the key technical fea-tures of the recently released HART Protocol Revision 7 (HART 7) standard:

• WirelessHART™ using IEEE STD 802.15.4-2006-compatible physical layer and MAC PDU to produce both mesh and point-to-point wire-less networks;

• Worldwide appeal using 2.4 GHz frequency- hopping, spread-spectrum technology;

• Enhanced data publishing modes, including one-way publishing of process and control values; spontaneous notification by exception; ad hoc request/response; and auto-segmented block transfers of large data sets;

• Dedicated bandwidth for high priority and peri-odic communications;

• Shared bandwidth to provide elasticity for event traffic and ad hoc request/response maintenance and diagnostic messages;

• Time-stamped data gathered at time of mea-surements in order to provide improved signal processing and control;

• Time-triggered actions/measurements for syn-chronized operation across multiple devices (e.g., vibration sensors);

• Highly secure communications using AES-128 bit encryption with individual Join and Session Keys and Data Link Level Network Keys;

• QoS messaging applied to all messages to ensure complete and prioritized delivery;

• Clear Channel Assessment channel-hopping, blacklisting, and adjustable transmit power support to maximize coexistence between WirelessHART™ networks and other ISM-band equipment;

• Multiple sequential data points of the same pro-cess variable in a single data packet;

• Command aggregation for embedded multiple

unchain youR daTa!

WirelessHART™— Information Unchained

WirelessHart™ releases the information trapped in your field devices with 100% backward-compatibility with your installed HART devices.

CT0709_Hart.indd 8 8/22/07 2:00:52 PM

read commands in a single transaction, giving faster con guration uploads;

• Backward-compatibility for the 24-plus million installed HART devices;

• Multiple power options capable of using long life batteries, solar, loop, or line power sources.

HART FOR PROFIT: USING THE DATAFrom its very beginning, the HART protocol has provided far more capabilities than con guring eld devices. First, it provides real-time device diagnostics as well as multivariable device infor-mation. When effectively used, HART information has repeatedly enabled companies to lower operat-ing cost and increase plant availability and reli-ability, thereby improving plant competitiveness.

“Yes, we’re going to move into WirelessHART,™ says Rob Brooks, process control supervisor, PPG Industries, Lake Charles, La., who has been experimenting with wireless for three years. “We already have an AMS system. Ease-of-use-wise and cost-wise, wireless is the way to go.”

In a traditional hardwired HART installation, a pair of wires connects the HART eld instrument with a host system. On that pair of wires are two signals, a 4-20mA analog signal that carries the

primary process measurement – ow, pressure, temperature, etc. Simultaneously riding on that same pair of wires is an all-digital signal that contains HART device information – secondary measurement values, device health, and other process and diagnostic information.

The release of the HART 7 standard added WirelessHART™ as an additional means of com-municating the all-digital HART diagnostic and multivariable device information and even the basic process variable, if required.

“While developing the WirelessHART™ stan-dard, the committee remained vigilant of two key requirements,” says Wally Pratt, the HART Communication Foundation’s chief engineer. “It must be easy to deploy, and it must be easy to use. There should be no need for users to learn about radio technologies, communication linking or become antenna experts.”

With the help of experts in process applications, wireless technologies and the HART protocol, the HCF thoroughly investigated wireless technolo-gies, assembled the best elements, and added them to the popular HART speci cation. The result is that WirelessHART™ complements wired HART; it does not replace it.


WirelessGateway

Wireless Access to HART Device Information

HART Data

DeviceManagementApplication

LegacyDCS

WirelessAdaptor

Existing HARTDevice

PV Data4-20 mASignal Analog

Only I/O

Device Status, Diagnostics, Configuration and more

Enabled by Wireless Adapter

Easy Access to Intelligent Device Information

WirelessHART™

Device

CT0709_Hart.indd 9 8/22/07 2:01:24 PM

HOW IT WORKSHesh Kagan, Invensys’ director of technol-ogy, explains, “WirelessHART™ and SP100 use the same radio and mesh networking stacks. Though WirelessHART™ has some underlying differences, it could certainly be run as one of SP100’s protocols.”

WirelessHART™ technology is based on the international radio technology standard, IEEE802.15.4 2.4GHz. These are low-power radios, making them ideal for industrial environ-ments, and they are cost-effective and available from multiple sources. Conforming to interna-tional regulations, a +10dBm ampli er is used that allows a device-to-device communication range of approximately 650 ft. (200m). All WirelessHART™ eld devices are required to be capable of routing messages from one device to another, effectively increasing the reach of a net-work beyond a single transmission link.

Major features of the WirelessHART™ proto-col include:• Time Division Multiple Access (TDMA) – This

technique provides scheduled transmissions over the network in a series of 10ms time slots. This coordinates data transmissions, reduces power consumption, and eliminates data collisions within the network, effectively using bandwidth and reducing communication latency.

• Frequency-Hopping – These techniques continu-ally switch transmissions among different bands. This prevents potentially disruptive radio signals from blocking WirelessHART™ transmissions.

WirelessHART™ uses the IEEE-de ned media access control (MAC) header, further ensuring robust, reliable co-existence with neighboring wireless networks.

• Fully redundant mesh networking − Wire-lessHART™ permits each device to transmit its own data and relay information from other devices in the network, giving highly reliable end-to-end data communication. Each transmit-ting device has two routes to send data to the network gateway. The alternate (self-healing) route is automatically established anytime a por-tion of the primary route is temporarily blocked either physically or by electrical interference.

• Enhanced security – WirelessHART™ employs robust, industry-standard authentication security techniques that help ensure that both the net-work and its data are protected at all times. This includes message con dentiality (end-to-end encryption), message integrity checking, authen-tication (message and device), and secure proce-dures for devices requesting to join a network.Thomas Holmes, president of MACTek de-

scribes the potential of WirelessHART,™ saying, “It expands the possibilities for users to gain access to valuable device information already sit-ting in their installed eld devices. Access to this information provides the key to lowering operat-ing costs while remaining competitive. In many cases, WirelessHART™ will allow users to have access to critical diagnostics and alarm informa-tion that would not be available using traditional wired HART technology.”

UNCHAIN YOUR DATA!


WirelessGateway

Wireless Access to Additional Process

MeasurementsPV + HART

Data

HostApplications

Field Powered

Battery, Solar or FieldPowered Devices

Minimal Installation Cost - No Wires

Wireless GatewayConnection to Plant Systems

+–

SolarPowered

BatteryPowered

CT0709_Hart.indd 10 8/22/07 2:01:42 PM

RemoteI/O Products

©2007 TURCK, Inc.

The best I/O available. No matter what I/O you need, we’ve got you covered. TURCK has a complete line of I/O products designed to save you time and money. With fi ve product families and thousands of part numbers, TURCK has exactly the right product for your applications. Many I/O products are custom designed for specifi c applications, including interfacing directly with motors, drives, valves, operator panels, push buttons and analog and digital sensors. With TURCK you don’t have to be locked into proprietary PLC I/O solutions. From your PLC to every point in your automation application, TURCK works! Visit our website today to order a Network I/O catalog containing over 590 pages of innovative products.

Call us with your next application:1-800-553-0016email: [email protected]

www.turck.com/process

MORE THAN JUST SENSORS AND CABLES...TURCK REMOTE I/O.

IF THIS IS HOW YOU THINK

OF TURCK,

BL67• Connectorized• Free confi guration software• Integrated valve interface

piconet®

• Miniature size• Connectorized• High-speed fi ber-optic subnet

AIM• -40° to 70°C• Rugged 50G shock/vibration• Fully encapsulated

OUTSIDE the Enclosure INSIDE the Enclosure

I/

O S

tati

ons

Modula

r I/

O S

yste

ms

BL20• Integrated motor starters• Free confi guration software• AC I/O

FD20• Highest density,

smallest footprint• Drive interface• OEM applications

WE’D LIKE TOMAKE SOME

IMPORTANT POINTS.

TUPA-168 TU-0907-25 Remote IO Ad1 1 8/22/07 12:43:04 PMCTHart_FPA.indd 11 8/22/07 1:51:16 PM


What WirelessHART™

Can Do For YouWhen facing new operational challenges, innovative companies

find solutions using wireless technologies.

WirelessHART™ is not just another piece of manufacturing bling—the equivalent of the newest “must have” cell phone

or MP3 player that, in reality, consumers can do just fine without. Rather, it extends the power of wired HART and has the potential to become an essential part of your process plant’s communica-tions network. It opens up new possibilities for measurement, testing, quality control, asset man-agement, and safety. What follows is an explora-tion of some of these potential uses.

Not just “part-time” help The truth is, and always has been, that HART communication does aid device commissioning and troubleshooting, but it is a “full-time” re-source, providing multivariable process data as well as device status and health information. And now, with the introduction of WirelessHART,™ each and every one of those features and benefits are easier than ever to collect.

Gareth Johnston, a Fieldbus communication specialist with ABB, says “The low cost of install-ing WirelessHART™ will result in the end user being able to install short-term or ad hoc process measurements to improve the view of the process, perhaps to solve quality issues.”

Marty Zielinski, Emerson Process Management’s director of HART and fieldbus technology, concurs. “WirelessHART™ can also be used to add new wireless measurement points at up to 90 percent lower installed cost than conventional wired points.”

Whether you need additional monitoring, easier ways to calibrate field instruments, better records of instrument configuration changes and calibra-tion records, online insight into instrumentation status, health and performance, assistance in

diagnosing and troubleshooting instrumentation, speedier commissioning, monitoring of critical data, or even supervisory process control, wired− and now WirelessHART™− is able to meet each and every one of those requirements.

the Way it could beSome major industrial users, such as BP and PPG, are installing prototype projects. Both companies have installed Emerson’s wireless systems, that company spokespersons have said are intended to be pre-standard WirelessHART™ devices that can easily be upgraded once the standard is completely released and certified devices are available. Other vendors, such as ABB, Honeywell, and Yokogawa, have also had beta test sites.

But because WirelessHART™ is so new, real-world examples are not available. So to explore the benefits of WirelessHART,™ we have provided four fictitious companies with real problems found in real process operations and that demon-strate the kinds of solutions WirelessHART™ can provide. Here are the real-world challenges faced by these fictitious companies.

• Everyday Chemicals wants to expand its prod-uct offerings and quickly learns that it also needs better visibility into its processes.

• Faced with aging instrumentation, no visibility about instrumentation health and performance, and ever-increasing customer demands for water, Mega-Metropolis Water Treatment needs a reli-able, cost-effective solution that can be updated over time and will reuse as much of its existing instrumentation infrastructure as possible.

• When Really Cool Colored Inks hires a new plant manager away from a competitor, it learns why its competitor is more efficient, agile, and

Wireless cuts the chaiNs

CT0709_Hart.indd 12 8/22/07 2:02:04 PM


A wireless signal has no way through obstacles.It will just bounce around.

At least the smart one will.

Introducing Emerson’s Smart Wireless – the secure, robust, self-organizing wireless network

that’s as easy to use as it is smart. With Smart Wireless, all the devices in the network can

communicate with each other. Whether it meets a permanent obstacle or a temporary barrier,

the self-organizing network automatically routes the signal around it. Smart Wireless is not

just flexible, it’s dependable – proven to deliver greater than 99% data reliability. To find why you should rely

on Smart Wireless from Emerson go to EmersonProcess.com/SmartWireless.

The Emerson logo is a trademark and a service mark of Emerson Electric Co. ©2007 Emerson Electric Company

Wireless1420 Gateway

Rosemount LevelMeasurement

Rosemount FlowMeasurement

RosemountPressure

Measurement

Rosemount TemperatureMeasurement

AMS Suite: Intelligent

Device Manager

Start bouncing signals today. SmartPack™ starter kitCall 1-800-999-9307 or go online to EmersonProcess.com/SmartPack

Pipes-Wireless_Horiz_FullPg.qxd:Control Spread 8/20/07 5:21 PM Page 1

CTHart_FPA.indd 14 8/21/07 9:43:39 AM

A wireless signal has no way through obstacles.It will just bounce around.

At least the smart one will.

Introducing Emerson’s Smart Wireless – the secure, robust, self-organizing wireless network

that’s as easy to use as it is smart. With Smart Wireless, all the devices in the network can

communicate with each other. Whether it meets a permanent obstacle or a temporary barrier,

the self-organizing network automatically routes the signal around it. Smart Wireless is not

just flexible, it’s dependable – proven to deliver greater than 99% data reliability. To find why you should rely

on Smart Wireless from Emerson go to EmersonProcess.com/SmartWireless.

The Emerson logo is a trademark and a service mark of Emerson Electric Co. ©2007 Emerson Electric Company

Wireless1420 Gateway

Rosemount LevelMeasurement

Rosemount FlowMeasurement

RosemountPressure

Measurement

Rosemount TemperatureMeasurement

AMS Suite: Intelligent

Device Manager

Start bouncing signals today. SmartPack™ starter kitCall 1-800-999-9307 or go online to EmersonProcess.com/SmartPack

Pipes-Wireless_Horiz_FullPg.qxd:Control Spread 8/20/07 5:21 PM Page 1


going the distance

Control_0907_Hon_IMC_Lifetime_Tr1 1 7/3/2007 11:07:42 AM


pro table: It’s using asset management software to access process and instrumentation information. Really Cool wants to move in the same direction.

• Giganto Re ning wants to extend the interval between planned maintenance shutdowns, but to do so and remain OSHA (Occupational Safety & Health Agency)-compliant, it needs a way to extend the full proof-testing intervals of its safety instrumented systems (SIS).

AD HOC MEASUREMENTSSometimes the addition of new measurement points can help improve product quality, process reli-ability or plant safety. Many modern analytical instruments provide multiple variables that are accessible via WirelessHART.™ By replacing obsolete, single-purpose instrumentation with HART-aware devices and adding self-powered WirelessHART™ adapters, new and/or secondary

process measurements can be provided easily and cost-effectively.

For example, Everyday Chemicals will replace several single-measurement temperature transmit-ters with dual-measurement tools. For each new transmitter, the original (primary) temperature measurement used the existing wiring and I/O channel and appeared on the operator’s graphic exactly like the old temperature measurement. The new (secondary) temperature measurement will be collected and reported via WirelessHART™ com-munication. Because of the ease of installation, Everyday Chemicals will be able to replace the old transmitters with new ones while the process remains operational.

When Everyday analyzes the cost savings of not having to add long runs of conduit and wire, not having to shut down the process, not having to re-do control system upgrades and con guration,


Gateway

Gateway

NetworkManager

Adaptor

Handheld

Field Devices

Process AutomationController

Host Application

Existing HART Devices

Host ApplicationNetwork

CT0709_Hart.indd 17 8/22/07 2:02:23 PM

and not having to retrain operators, it will be able to add several WirelessHART™ process measure-ment points that increase process visibility. Armed with new process insights, the operators will be able to significantly improve Everyday Chemicals’ product quality.

Aging instrumentAtionWhen you read articles in trade publications or at-tend conferences and user group events, it’s easy to forget that not everyone has installed cutting-edge digital fieldbus. In fact, there are still many plants with decades-old pneumatic instrumentation.

A significant number of process control instal-lations have yet to make it to the 4-20mA analog electronic era, and there are boatloads of pre-HART 4-20mA instruments and another boatload of HART instruments that are under-utilized throughout the world.

Because WirelessHART™ is fully backward-compatible, it opens up all sorts of opportunities to use those thousands of miles of existing wire to ease replacement of aging instrumentation as well as begin using HART information to improve pro-cess reliability, availability, and plant utilization.

Like many utilities and municipalities, Mega-Metropolis Water Treatment cannot justify a rate increase to cover the cost of upgrading to digital fieldbus technologies. However, it also cannot afford to maintain the status quo; it needs a reliable, cost-effective solution that can be updated over time and reuse as much of the existing instrumentation infrastructure as pos-sible. Enter WirelessHART.™

By conducting an in-depth instrumentation audit, Mega-Metropolis will be able to develop

an upgrade plan that can be accomplished within existing budget constraints.

Mega-Metropolis will develop a three-year plan to replace aging, but critical existing instruments with new HART instruments, each fitted with WirelessHART™ adapters.

Less critical instruments will be placed in the “replace-on-failure-pay-out-of-maintenance” category. Anytime one of these instruments fails or otherwise qualifies for replacement, Mega-Me-tropolis will purchase a HART instrument with a WirelessHART™ adapter and pay for it using money from its maintenance budget.

Because this plan uses existing wiring, instru-ment replacements will be easy to install, calibrate, and commission. After a minor upgrade to existing handheld configuration devices, Mega-Metropolis also will be able to configure the new WirelessHART™ parameters. With rare exceptions, a measurement will be offline for less than one hour. Armed with new process information, Mega-Metropolis Water Treatment will find it can im-prove filter efficiency and thus filter maintenance, thereby maximizing chlorine effectiveness. The ability to analyze HART information also will en-able Mega-Metropolis to reduce filter maintenance frequency, thereby freeing up more maintenance dollars to purchase additional HART instruments.

mAnAging AssetsThe efficient management of a business’s assets is really what CEOs are expected to do, and how well they do it is what Wall Street analysts use to reward or punish a company’s stock.

Asset management information is a critical predictive maintenance component, but that’s only one of its benefits. It can also capture important institutional knowledge.

Like an increasing number of companies, Really Cool Inks specializes in producing “designer prod-ucts”; that is, products designed to meet specific customer and/or niche markets. The upside of de-signer products is the potential for greater profits; the downside is that frequently a significant amount of time elapses between production batches, and product formulations aren’t well-documented or universally understood by operators.

Really Cool Ink’s new plant manager understands that in order to capitalize on the upside of designer products, his plant needs to minimize the downside impacts, and that means establishing a robust asset

sAfety expert Weighs inWhen asked about the benefits of using HART process and device information to extend safety system proof-testing intervals, exida founder and recognized safety instrument-ed system expert, William Goble, said, “I believe that the use of HART in SIS for purposes of performing proof-testing or semi-automatic proof-testing could be very valuable. I see an increasing number of SIS manufacturers adding HART AI/AO input modules. The downside of HART is that configuration variables can be accessed and changed via handheld communicators. Some safety transmitters require that HART be disconnected during safety operation, as the devices’ software and hardware do not provide specific protection against that possibility.”

Wireless Cuts the ChAins


CT0709_Hart.indd 18 8/22/07 2:02:35 PM

going the distance

Control_0907_Hon_IMC_Lifetime_Tr1 1 7/3/2007 11:07:42 AM


management infrastructure that can capture the deep process knowledge that resides in experienced operators, maintenance technicians, and senior automation engineers.

Using a similar, but a more aggressive approach than Mega-Metropolis Water Treatment, Re-ally Cool Ink’s plan includes using the control system and a robust process-variable historian to identify the “gold production standard” for each product, with full recognition that because some products are so infrequently produced, it will take years to develop the entire gold-standard library. Nevertheless, Really Cool Ink’s initiative isn’t about quick profits; this asset management endeavor is viewed by the entire company as strategic to its long-term success. Therefore, the chief executives are committed to the tactical implementation of the plan.

To ensure that as much in-process information as possible is captured, Really Cool Inks is identi-fying the critical measurements and replacing all the non-HART instruments with HART-enabled and WirelessHART™ devices and adapters. During the initial instrumentation audit, Really Cool Inks has been pleasantly surprised to find that many of its instruments are already HART-capable, but because they had been installed to help simplify commissioning and calibration, device diagnostic and process information has not been collected from a single instrument.

Really Cool Ink is still in the early stages of its plan to capture exactly what is required to become more efficient, agile, and profitable in the delivery of designer products. However, it knows one thing for sure; WirelessHART™ is one of the critical components to its success.

Safety inStrumented SyStemSDuring the past couple of years, process indus-try safety standard IEC 61511/ANSI/ISA 84.0.1 and its related safety instrumented systems (SIS) have been grabbing more and more headlines. At the same time, ever-increasing energy demands are forcing companies like Giganto Refining to seek ways to extend the interval between planned maintenance shutdowns (outages) while remaining OSHA regulation-compliant.

While examining what will be required to extend the interval between planned outages, one of the problems Giganto engineers have identified is the safety criteria used to design its SISs. Unless Giganto’s engineers can find a way to extend the interval between when the SIS is fully proof-tested – a complex test that requires the process to be shut down – it will not be possible to extend the interval between planned outages.

Consistent with good engineering practices, Giganto uses hardwired instruments as SIS inputs. To facilitate commissioning and calibration ef-forts, HART instruments have been purchased and installed. Though Giganto’s engineers are aware of the process and device diagnostics available in HART devices, efforts to collect and analyze the information have yet to be undertaken.

Now, with an urgency to extend the interval between full proof-testing, Giganto’s engineers are taking a hard look at HART information, espe-cially clause 3 of the IEC 61511 standard.

Clause 3 defines, among other things, the safe failure fraction (SFF): the fraction of safe failures and dangerous detected failures in relation to the total failures. After consulting with safety system consultants, Giganto’s engineers are convinced that by adding asset management software and WirelessHART™ adapters to its existing SIS HART devices, they will be able to use the HART process and device diagnostics to improve the system’s SFF and thereby extend the time be-tween full proof-testing.

What makes the WirelessHART™ adapters espe-cially attractive is that each can be added anywhere along the transmitter wires, and the new devices do not introduce any common-cause faults.

To minimize the possibility that the HART con-figuration variables of the safety system transmit-ters might be inadvertently changed via a handheld communicator, Giganto engineers will place each safety system transmitter in a double-locked instru-

mix & match? no ProblemFew, if any, process plants use only one instrument com-munication means. Older plants still have miles and miles of wire. Plants using digital fieldbus communications (i.e., DeviceNET, Foundation, Profibus, etc.) likely have installed different communication protocols to meet different requirements. The result is often a plant with a little-of-this and a little-of-that, which when examined as a whole, produces the simple question, “Is there an easy way to get information from these multiple communication protocols into one collector (repository) device?”

Now, with the introduction of industrial wireless, the answer has become much simpler; You bet there is and WirelessHART™ is part of that solution!

WireleSS cutS the chainS


CT0709_Hart.indd 20 8/22/07 2:02:50 PM

ment enclosure and place one key under the control of the maintenance shop foreman and the second under that of the operations supervisor.

Through the use of WirelessHART,™ asset management software and some clever physical transmitter configuration security plans, Giganto Refining will be able to improve the SFF of its safety systems, thereby extending the interval be-tween full proof-testing and, in turn, extending the interval between planned maintenance shutdowns (outages), all while remaining OSHA regulation- and IEC 61511- conformant.

AdditionAl wireless opportunitiesThough early deployments of WirelessHART™ are expected to be adaptors installed on hardwired devices, the HART 7 standard does provide for fully wireless HART deployments.

Beyond process monitoring, wireless is a natural fit to provide a cost-effective means for health, safety, and environmental monitoring in such areas as area gas detectors, water effluent, gas emissions, relief devices, steam traps, and safety showers.

AreA gAs detectors Many process plants require numerous gas detec-tors throughout the plant to ensure that the air is safe to breathe and to work in. Wireless detectors will not only provide an efficient means of provid-ing an alert to operators, but also to monitor the operational status of the devices.

wAter effluent, gAs emissions,And relief devicesThe quality of any liquid or gas leaving a pro-cess facility is vitally important to maintaining environmental quality. Regulations are requiring more measurements at more frequent intervals to ensure compliance and decrease the num-ber of fugitive emissions. Specifically, Wire-lessHART™ devices could be used to monitor the opening of relief valves or the condition of rupture disks. By connecting the wireless data to the environmental monitoring software for the plant, WirelessHART™ devices can provide an easy, cost-effective way to audit the required measurements without extensive modifications to existing control systems and plant wiring. Since many effluents aren’t located conveniently close to the center of the plant, the ability of WirelessHART™ devices to operate on batteries

and completely wirelessly makes these measure-ments possible after all.

steAm trAps As energy prices rise, it becomes increasingly important to limit the amount of energy wasted. Plants often have many steam traps, and these can be easily monitored for unusual steam flows, allowing notification of a need for correction of faulty operation that might otherwise go unno-ticed for some time.

“We’re doing some temperature profiling on a stagnant steam line that is out in the middle be-tween two major parts of the plant,” says PPG’s Rob Brooks, “where there aren’t even junction boxes.” WirelessHART™-enabled sensors can save thousands of dollars in steam costs for very little outlay.

sAfety showers In the United States, OSHA’s First Alert Response guidelines require that plant operators be alerted within 10 seconds of an activated safety shower. Many remote safety showers are located in haz-ardous locations with no existing signal wiring. A self-powered WirelessHART™ pressure transmit-ter could be used and would only be required to switch on its radio when the safety shower is oper-ated or for remote diagnostic checking.

proceed with confidenceWirelessHART™ is an extension of the well-known, widely accepted and proven-in-use HART Communication Protocol that has helped improve thousands of process control facilities worldwide. You already have the instruments; now you can unchain the data in them. By updat-ing the device description file, the same tools you already use become suitable for use with Wire-lessHART™ devices. WirelessHART™ devices can be configured wirelessly too. WirelessHART™ uses the experience and knowledge gained using HART to minimize training and simplify mainte-nance and support activities.

With WirelessHART™ you are assured of the same attention to interoperability and robustness you’ve come to expect of wired HART. You get to use the same instruments in the same way, and you get the extra benefits. Like its wired counterpart, WirelessHART™ technology ensures your invest-ment will be protected well into the future.


CT0709_Hart.indd 21 8/23/07 9:56:57 AM


How to Get Unchained with WirelessHART™

Deploying any industrial wireless network requires addressing physical and security related issues, however WirelessHART™ offers several

advantages over other wireless alternatives.

“Many control systems do not provide access to HART data,” says Yokogawa’s Manager, Field

Instruments, Kaoru Sonoda, “and wireless technol-ogy can be a practical and cost-effective solution.”

The solution is not to require control system vendors to revise, or end users to rip and replace existing control systems, but rather to enable them to do an end run around the problem. But increased demands on operators and maintenance demand a simple, effective solution.

Enter wireless.“Wireless technology has now been tested,” Sono-

da continues, “and we believe it is capable of meeting the critical demands of the process industries.”

Gareth Johnston, fieldbus communication specialist with ABB, says, “WirelessHART™ has been designed to simplify commissioning and lifetime support. The specification team always had it in mind to keep it as simple as 4-20mA. The result is that users can employ

existing knowledge and software tools to support WirelessHART™ instruments and adapters.”

Flexibility by designAccording to Guido Stephan, director technology and processes, automation, and drives, sensors and communication, R&D technology & pro-cesses, Siemens AG, “WirelessHART™ commu-nication will not replace wired HART, but it will offer access to diagnostic features of field devices and will allow additional applications not pos-sible with wired devices.”

WirelessHART,™ part of the new HART 7 standard, provides four ways to acquire data from field devices.

The first two are the traditional wired methods, with the primary physical variable on the 4-20 mADC loop, and the digital data (diagnostics, secondary physical variables, alarms, etc.) carried on the wire and pulled off at the control system or by a handheld calibrator.

The two new ways are1) Wireless adapters for existing field device,2) WirelessHART™ field devices, with or

without wires.The wireless adapter is designed to retrofit

any of the more than 24 million existing HART devices and provides wireless access to both the primary process variable and all the digital data from the device. A WirelessHART™ field device can be installed with or without 4-20 mA loop, can operate on battery power, and provides the same data access as the adapter. The wireless data is transmitted to a gateway, which connects to the control or asset management system.

Figure 1. WirelessHART™’s mesh network architecture al-lows relatively easy installation, often without an extensive site survey. The self-organizing and self-repairing nature of a mesh network is well-suited to the industrial environment.

Mesh network architecture

getting unchained

CT0709_Hart.indd 22 8/22/07 2:03:18 PM

As with all previous upgrades to HART standards, HART 7 and WirelessHART™ are completely back-ward compatible to any installed field device.

Now is probably a good time to reiterate that HART information – diagnostics, health, second-ary variables, etc. – is communicated digitally on the same pair of wires as the 4-20mA pri-mary measurement signal. Implementing Wire-lessHART™ simply provides another means of accessing that same HART information and more.

WirelessHART™ technology is based on IEEE 802.15.4 2.4GHz radio technology. The low power requirements of radios designed to this standard make them inherently suitable for lowpower mesh networks, and because of international standards, these radios are cost-effective and available from multiple sources. To ensure conformance to inter-national regulations, each radio includes a +10dBm amplifier that supports a clear-path transmission range of approximately 650 ft. (200m). Additionally, to extend the reach of the wireless network, each field device is required to communicate its own data messages, as well as being capable of passing on data messages received from neighboring devices. (See Figure 1.) The flexibility of WirelessHART™ provides multiple options for device placement to extend both the reach and reliability of the network.

PlanningThough the underlying technology of Wire-lessHART™ all but eliminates the need to conduct complex site surveys, no one is so naïve as to believe that network robustness, maintenance, and ease of future expansion (scalability) can be achieved without some degree of up-front planning.

To ensure a WirelessHART™ installation meets performance expectations, users should examine these four areas:

1) Physical layout,2) Reliability, security and coexistence,3) Commissioning, 4) Operation and maintenance.

Physical layoutWhen users begin planning an industrial wireless network, a plant walk-through reveals the physical difficulties of achieving clear-path transmissions of

even a few hundred feet. Beta testers have reported that they have installed a gateway and carried a wireless instrument around to check location and quality of signal, rather than doing an extensive survey. Typically process plants have both inter-mittent and permanent obstacles that are likely to reduce, often times significantly, a user’s ability to establish wireless communication between field-mounted devices. WirelessHART™’s mesh network simplifies this issue by providing multiple paths around obstacles, including the ability to go point-to-point, not just mesh.

Having the flexibility to locate HART wireless adapters anywhere along the wire can simplify installation, maintenance, and security signifi-cantly, as in the case of the wireless adapters inside a marshalling cabinet where distances are minimal and intrinsic safety isn’t an issue (Figure 2). Like-wise, a transmitter can be placed in an otherwise inaccessible location, say, under a large reactor, and the adapter located in a location where clear-path transmission is available. No other wireless methodology provides this flexibility.

Once a physical WirelessHART™ device layout plan is developed, the next step is to examine reli-ability and security requirements.


4-20mAwith HART

4-20mAwith HART

4-20mAwith HART

4-20mAwith HART

4-20mAwith HART

WirelessHART

FieldJB

Mar

shal

ling

pane

l

Figure 2. Fully developed, a HART network uses Wire-lessHART™ to unchain the valuable diagnostic and process data locked inside existing systems and provides for future expansion with a choice of wired or wireless field devices.

Mesh network architecture

CT0709_Hart.indd 23 8/22/07 2:03:47 PM

Reliability, SecuRity & coexiStenceUnderstandably, reliability and security ranked high among end-user concerns during initial discussions about deploying wireless technolo-gies within the process industry. To that end WirelessHART™ addresses reliability and security concerns by using robust, well-proven, and highly effective techniques. In fact, when combined with built-in good neighbor/tolerant neighbor co-existence features, WirelessHART™’s use of fully proven mesh network routing techniques make it highly reliable.

Like any good neighbor, WirelessHART™ de-vices try to avoid bad behaviors, such as talking (transmitting) too loudly, talking too often, talking too long and/or using the entire frequency band, that affect others. Tolerance is a second charac-teristic of being a good neighbor. Within a wire-

less network, tolerance means that receiver nodes tolerate interference caused by other nearby radio frequencies or the occasional mistake, doing what is necessary to prevent data loss. WirelessHART™ transmitters can also use a power turn-down fea-ture to reduce the reach and/or range of the signal to avoid network conflicts.

WirelessHART™’s robust security measures protect the network and its data at all times. They include message confidentiality (end-to-end encryption), message integrity checking, message and device authentication, and secure procedures for devices joining the network.

Industry standard techniques are used to provide authentication and encryption. Wire-lessHART™ also gives users the flexibility to apply their own network security strategy while prevent-ing security from ever being disabled.

GettinG unchained


GettinG youR Feet Wet

You may have 50 or 5000 HART-enabled devices in your plant, and all of them are working, doing their jobs. You might not want to do anything to disturb them while they work until you have some more experience with the new WirelessHART™ technology.

So what to do?You can gain experience with unchaining your HART data one

of two ways. First, you could find a place where you’d like to monitor process variables, but because of the expense, you’ve never been able to justify doing it before.

BP’s Cherry Point, Wash., refinery did that in the most publi-cized beta test of Emerson’s SmartWireless system.

SmartWireless was designed as a WirelessHART™ precursor; that is, the system was designed to take HART data wirelessly, using hardware and firmware that approximated a best estimate about the final standard. Emerson publicly stated at the time and has reiterated since, that SmartWireless was capable of and in-tended to be upgraded to WirelessHART™ as soon as the standard was released and products were certified and available for sale.

Marty Gering, wireless data collection coordinator and wire-less worker administrator for the refinery, was in charge of the demonstration installation. Although Cherry Point is actually the second-newest refinery in the U.S., there are many locations where large bodies of uncaptured data exist.

"This data is valuable," Gering said at Emerson Exchange 2006 when he discussed the installation, "but we can't touch it because of the expense of wiring and running conduit. Lube oil and bearing temperatures, among other values, are just left out of the picture."

Gering is at work on another project now: the tank farm. Cherry Point was built to be a 95,000 bbl/day refinery and

One of the beauties of the WirelessHART™ standard is

that the wireless adapter does not need to be located at the transmitter.

This field device is installed at PPG Industries’ Lake Charles, La., facility and transmits HART data entirely wirelessly. (Photo courtesy of Emerson Process Management)

CT0709_Hart.indd 24 8/22/07 2:04:22 PM

As you prepare to install and then commission WirelessHART™ systems, remember that your expe-rience, training, and tools used for HART-enabled devices apply to WirelessHART.™

WirelessHART™ devices are configured and installed in much the same way as they have been in the past, protecting your investment and maintaining the HART experience of being easy to use. After the WirelessHART™ adapters are in-stalled, commissioning can begin. Actually there are two parts of commissioning–network com-missioning and device commissioning.

NETWORK COMMISSIONINGNetwork commissioning begins when the gateway device is powered up and begins advertising. Being the rst device in the network, the gateway estab-lishes its own schedule that synchronizes nodes as

each one joins the network. But rst, the network manager, which may or

may not be hosted in the gateway device, must be con gured with the correct network ID and device password(s). Once that is done, the network manager will automatically adjust the network’s schedule based on the requirements reported by each device as it joins the network.

Because WirelessHART™ provides an additional means of collecting HART information, the com-missioning procedure is similar to that for wired systems. Using existing HART con guration tools, such as a HART handheld con gurator or per-sonal computer (PC) application, users only need to con gure three additional parameters–device password(s), network ID and device refresh rate.

Existing handheld or PC applications can also provide a status display of the joining process


Control Loop Controller

WirelessHART™ network using adaptors for existing instruments

AssetManagement

Sysytem

WirelessHART™

gateway

To controlsystem

HART data to PC via OPC or

other protocol

has now become a 245,000 bbl/day refi nery just by increasing throughput and optimization. The tank farm was built with only level and, in some cases, temperature sensors, and Gering wants to access that information wirelessly.

"We're beginning a new project to connect those tanks wire-lessly with backup level. We also have hundreds of valves that we'd like to have positioner information on, as well as other pressures and temperatures," Gering announced. "We have mixers with mo-tors we'd like to monitor current on, and lots of other things. We're looking at 300 points. We want to fi nish the engineering this year and have a big start on implementation by the end of 2007."

In addition to the wireless field device Gering is using, the second path to unchaining HART data is only now be-coming available. One of the beauties of the WirelessHART™

standard is that the wireless adapter does not need to be located at the transmitter. It can be located anywhere along the 4-20 mA current loop.

As soon as adaptors become certifi ed for compliance, you’ll be able to buy and try them out on existing wired HART instru-ments where you already know you want the data inside them. This will require NO rewiring and will not require taking the instruments or control valves out of service at all.

CT0709_Hart.indd 25 8/22/07 2:04:41 PM

AffordAble dd bAsed ConfigurAtion using Your PC

ProComSol, Ltd designs and manufactures both the hardware and software needed to perform complete HART device configuration and monitoring using your PC. DevCom2000 software uses the registered DD’s from the HART Foundation, allowing full access to all device parameters, including Methods. The HM-USB USB HART modem and the HM-BT-BAT Bluetooth HART modem offer significant cost savings and productivity benefits. Units meet industry standards for USB, Bluetooth, and HART connectivity. Order this affordable solution online using our secure website.

ProComsol, ltdProcess Communication SolutionsTel. 216.221.1550 • Fax 216.221.1554 • www.procomsol.com • [email protected]

and will quickly help pinpoint any communica-tion issues. These devices also can provide access to diagnostics and supporting device calibration and maintenance operations.

deviCe CommissioningThe final step to commissioning a Wire-lessHART™ network is to complete device verification and conduct a loop test of any wired devices. WirelessHART™ devices need no 4-20 mA loop, and have a maintenance port for test-ing. Commissioning and maintenance are done via standard commands or DDL.

When so specified on the purchase order, device manufacturers put device tags and other identifi-cation and configuration data requested the user into each field instrument prior to shipment. After installation, the instrument identification (tag and descriptor) can be verified in the host system using a configurator (handheld communicator or PC).

Some field devices provide information on their physical configuration (e.g., wetted materials). These and other configuration data can also be verified, thereby ensuring the installed instrument is suitable for the application. Such verifications are important for regulatory health, safety, and environmental con-formance, as well as ISO quality requirements.

Loop integrity is important when commission-ing a device. For HART-enabled devices, analog loop integrity can be checked using a loop test feature, available in many HART devices. The loop test feature enables the analog signal from a HART transmitter to be fixed at a specific value so total loop integrity from device to indicators, recorders, and operator displays is correct.

Additional integrity can be achieved if the ana-

log value of the primary variable (PV) is compared to the digital value being reported from the device. For example, someone might have provided an offset to the 4-20mA analog value that has not been accounted for in the control system. Compar-ing the digital value of the PV to the analog value verifies the entire loop is properly calibrated.

Consistent with wired HART, theWire-lessHART™ specification allows wireless devices and wired devices using adapters to simulate a process value to accommodate loop testing, al-lowing verification of data across the network, through the gateway, and into a host application. A wireless device can be set to transmit a fixed value in order to conduct this important test.

Many HART configurators provide easy ways of collecting, archiving, and/or printing commissioned device information. Because WirelessHART™ uses the same configurators as hardwired HART, existing procedures for collecting and recording “as-installed” device configuration data, calibration records, and other device records remains essentially unchanged.

WirelessHART™ is the first open and interoper-able wireless communication standard designed to address the critical needs of process industry users. It has been carefully designed and thoroughly tested to provide reliable, robust, and secure wire-less communication in real-world industrial plants.

WirelessHART™ provides new ways to gather information on process parameters and monitor the performance of plant assets in areas that have previously been difficult to achieve either techni-cally or cost-effectively. It extends the power of HART into areas that were difficult to reach with conventional wired systems, and it provides low-cost digital access to existing HART devices.

getting unChAined


CT0709_Hart.indd 26 8/22/07 2:05:03 PM

Pulling out and reinstalling a reversed dP takes time

and costs money. That’s why the 364 lets you select your

High and Low side with the push of a button - regardless

of orientation to your primary element. So you can

complete your start up on-time and on-budget every time. The 364 - more

functionality in one device.

Visit us at www.abb.com/pressure to learn more about

the “all-in-one” 364.

The innovative 364 dP transmitter.

© Copyright 2007 ABB.

Ever installed a dP backwards? Eliminate rework with reversible polarity.

Free Flowmeter Handbook Offer! Visit www.abbinfozone.com

This side up_HART.indd 1 8/15/07 12:51:38 PM



Documents

HART 6.1 Application Guide