The Past, Present and Future of Device Level Communication in the Process Control Industry

1 ITI 780 Technology Management

The Past, Present and Future of Device Level

Communication in the Process Control Industry

M.C. Simjee

Abstract

This paper evaluates the communication network which provides the interface between field devices

and the Distributed Control System in the process industry. The evolution of technology is evaluated

using the principle of S-curves, in order to identify the factors which resulted in the switch to new

technologies. Technology Space Maps are used to audit the position of the Control Engineering

Group of Sasol with regard to these communication technologies. The methodology of the

Technology Readiness Level is used to evaluate the maturity of the WirlessHART technology, which if

successfully implemented will become the technology of the future.

1 Introduction

1.1 Company Profile

Sasol Technology is a subsidiary of Sasol Limited which is tasked with managing research and

development, technology and innovation, engineering and project management portfolios. Within the

engineering portfolio of Sasol Technology lies Sasol Technology Control Engineering, which is the

focal point of this paper. The Control Engineering group provides control system related engineering

recourses to the all Sasol Business Units (SBU’s) worldwide and aims to provide SBU’s with a

competitive advantage by providing appropriate technology solutions and services. The group’s

responsibilities include developing and maintaining specifications, providing engineering recourses for

the execution of projects and provides specialised services in order to aid in plant optimisation

activities.

1.2 Problem Statement

During the past four decades control systems in the process control industry have evolved

significantly in order to maximise on the benefits brought upon us by the information age. As the

volume of information available on the plant floor increases, effective communication needs to be

established in order for higher level systems to take advantage of this data. The Control Engineering

group is responsible for the selection of the communication technologies which provide the interface

and is faced with a myriad of challenges during the selection process. In order for the implementation

to be successful, a balance between financial and production needs, must be achieved whilst still

maintaining the levels of safety, integrity and reliability which the process industry demands.


2 Literature Study

2.1 S-curves

The S-curve concept was introduced by Foster (1986) to describe how the performance of a specific

technology varies over time. The underlying principle is that the performance of a technology

increases with increased effort, but eventually reaches an upper limit where further improvement is

either impossible or so expensive that it is no longer feasible. To achieve higher performance,

requires changing to a different technology, which in turn follows its own S-curve. The new S-curve

may start at a performance level lower than the previous one, but it has the potential to surpass its

predecessor.

Twiss (1980) stated that progress was not random, but followed a regular pattern when specific

criterions are plotted against time. The graphical representation of the S-curve indicates slow growth

in the early phases, followed by exponential growth as the technology becomes better understood. As

performance approaches its upper limit development decreases. This upper limit is normally defined

by perception of a particular technology and is rarely clearly defined.

The gradient at any point on the curve indicates the productivity derived from the resources which

have been allocated to a specific technology. Figure 1 below provides a graphical representation of a

technology S-curve.

Time/Engineering Effort

1

2

31 Slow Initial Growth

2

Incremental Growth3

Rapid Exponential Growth

Figure 1: Graphical Representation of an S-curve


2.2 Technology Space Maps

Pretorius (2001) provides a real world application for the use of technology space maps, indicating

that assessing a company’s technological capability is vital in maintaining its competitive position in

global markets.

De Wet (1992) introduced the concept of a technology space map as a tool for communicating

technical issues in a simple manner. For corporate strategy to encompass technological issues

communication between the executives and technologists is essential. Thus, technology space maps

are a means of simplifying complex technical issues in a manner that executives can quickly and

easily gain a broad outlook of the current and future environment from a technologist’s perspective.

A S-L-H Map is the most frequently used representation of the technology space. It consists of two

dimensions namely, system life cycle and system hierarchy. However, the technology space map can

be customised for individual needs in order provide information which is most vital to a specific

company or industry. The S-L-H map is illustrated in Figure 2 below.

The technology space map can be used in a variety of technology management environments. It

provides an audit of the present status of the technological capabilities within a company and provides

a means for the planning of future requirements in line with a company’s goals and objectives.

Further, the technology space map provides a holistic outlook on a company thereby allowing for

technology gaps to be identified and provides a platform for these gaps to be addressed.

Research Design Develop Produce Maintain Use

User System

Prod. System

Product

Subsystem

Component

Material

System Life Cycle Phases

System

Hierarchy

Level

Figure 2 : S-L-H Map indicating the system hierarchy and system life cycle


2.3 Technology Readiness Level

Mankins (1995) described Technology Readiness Levels (TRLs) as a systematic measurement for

assessing the maturity of a particular technology. The General Accounting Office of the U.S.A. in a

1999 report stated that failure to adopt mature technologies almost always impacted negatively on

both cost and schedule, when these technologies were being implemented. The report states that

certainty of technology maturity must be established before its inclusion as part of a system and

states that the evaluation of technology maturity is an international best practice.

The TRL approach has been used by NASA since the 1970’s and has since been optimized until

recently incorporated into NASA Management processes. The model has been generalized and

adapted by the United States Department of Defense (USDOD) and is used extensively in its

weapons acquisition programs. Table 1 provides a basic description for each TRL level. In order to

aid uses of the TRL methodology the USDOD has created a more detailed explanation of each TRL

level which has been included in the appendix.

Table 1: US Department of Defence TRL Definitions

TRL Level Definition

1 Basic principles observed and reported

2 Technology concept and/or application formulated

3Analytical and experimental critical function and/or characteristic proof of

concept

4 Component and/or breadboard validation in laboratory environment

5 Component and/or breadboard validation in relevant environment

6System/subsystem model or prototype demonstration in a relevant

environment

7 System prototype demonstration in an operational environment

8 Actual system completed and qualified through test and demonstration

9 Actual system proven through successful mission operations

The TRL level of a specific technology is evaluated through the use of a spreadsheet known as the

TRL calculator which is freely available for download from USDOD website. The spreadsheet

contains pre-programmed macros and a series of questions which once answered provides an

analysis of the maturity of a technology at a specific point in time. Since, the same questions are used

each time a technology is evaluated, the tool can also be used compare the maturity of multiple

technologies with respect to each other.


3 Application of Theory

3.1 The Evolution of Industrial Process Communication

Until the 1960’s industrial process control was achieved through the use of dedicated pneumatic and

modular electronic controllers. The Computer Integrated Manufacturing (CIM) era brought the

minicomputer to the manufacturing environment which led to the introduction of the first Distributed

Control System (DCS). The DCS revolutionised the process control industry providing operators the

ability to monitor and control the entire process from a centralised location. In order for the DCS to

receive data from field instruments (e.g. flow meters) and transmit data to control elements (e.g.

valves) and extensive communication network was required. It is this communication network which

interfaces the DCS to the field devices which is the focal point of this evaluation.

During the early phases of the CIM era various analogue communication protocols were introduced

which used variations in voltage or current to represent data. The 4-20 mA (four to twenty milliamp)

standard emerged as the victor and was eventually adopted by all users in the industry. The 4-20 mA

standard remains the dominant communication protocol across Sasol plants globally as is thus where

the evaluation begins.

The 4-20 mA standard has dominated the process control industry for over 30 years. It provides

reliable and robust communication in a demanding environment especially where safety critical

systems are involved. The primary disadvantage of the standard was that only one process variable

could be transmitted across a dedicated copper cable. This limiting factor was perceived as the upper

limit of the technology.

The 1980’s saw the introduction of intelligent field devices which had the ability to perform self

diagnostics as well as perform rudimentary analysis of the process variable. However, this data could

only be accessed by an operator in the field. The market demanded higher bandwidth, but technology

development in the area of busses was still in its early phases.

The introduction of the HART (Highway Addressable Remote Transducer) protocol in the 1980’s

provided a solution that the market demanded and resurrected research and development in the

4-20 mA standard. The HART protocol modulates the 4-20 mA current with a low level frequency shift

key sign wave signal without affecting the analogue signal. Simply put, a digital signal is

superimposed on to the analogue signal thus increasing bandwidth whilst using the existing cable

infrastructure. Thus the perceived limit of the 4-20 mA standard was exceeded in terms of both cost

and bandwidth. The virtually unanimous adoption of the 4-20 mA HART standard clearly highlighted

the two critical performance criteria which were cost and bandwidth. Further the situation highlights

the reluctance of the industry to change to radically new technologies. Using Moore’s (1996) model of

the technology adoption life cycle, the industry could be described as the late adopters or even the

laggards. The primary reason for this stance is that the process industry demands a high level of

maturity in technology before its implementation especially with regard to the number of hours of field


testing. The diagram in Figure 3 illustrates the situation faced by the industry when the HART protocol

was adopted. The product performance assessment has been based on bandwidth and cost.

Figure 3: S-Curve representation of field communication between the 1960's and 1980's

The network centric era of the 1980’s brought distributed intelligence to the plant and established the

microprocessor in process control. With this the DCS became more than just a basis for process

control. Emphasis was being placed on the integration of the corporate board rooms to the factory

floor. The adoption of the Ethernet and the TCP-IP protocol in the industry allowed for the integration

of the hierarchal layers above the DCS namely the MES (Management Execution System) layer and

the ERP (Enterprise Recourse Planning) layer. However, only limited data could be obtained from the

field and thus the market demands for bandwidth increased. Further, the high costs of installing a 4-

20 mA network was becoming ever more apparent as copper prices increased, especially when

compared to the installation costs of Ethernet based networks.

However, implementation of the TCP-IP Ethernet in the process industry was not feasible, primarily

because the there is no guarantee of the sampling rate i.e. it may take significant time before data is

communicated to or from a field device. This was a serious concern in the industry especially with

regard to instruments which provided safety functionality.

Further development in digital communication led to the introduction of bus based protocols namely

Foundation Fieldbus, Profibus and Devicenet. The fundamental characteristics of these protocols are

the same and for the purpose of this paper will be referred to as bus protocols. The introduction of

these protocols in the mid-1990’s threatened the long standing dominance of the 4-20 mA and 4-20

mA HART standards. The bus protocols were entirely digital, thus providing effectively four times the

bandwidth of the 4-20 mA HART standard (31.25 kbit/s of Foundation Fieldbus H1 compared to 7

kbit/s of 4-20 mA HART). The bus protocols provided the market with the bandwidth requirements

which it had demanded for over a decade. The use of a digital backbone allowed for the creation of

multidrop networks which meant that each field device no longer needed a dedicated cable (The

Foundation Fieldbus H1 standard allows for up to 16 devices per segment). This feature of the Bus


protocols significantly reduced the install cost per device and used the same medium as the 4-20 mA

standard which allowed for cost effective system overhauls. Tolfo (2004) indicates that a 40% saving

on cable expenses can be achieved through the use of Foundation Fieldbus over a 4-20 mA

installation.

The added bandwidth provided by the Bus protocols allowed for the control of the field device to be

done in the field. No longer was data processed in the DCS but rather the field devices did all the

required computation to perform control activities autonomously. This significantly reduced the

hardware costs of the traditional DCS systems as its primary activity was reduced to simply

monitoring the field devices.

The Bus protocol also brought significant cost savings with regard to maintenance. The increased

bandwidth allowed for greater levels of diagnostic data to be relayed back to the DCS where it could

processed by asset management systems allowing for predictive maintenance activities thereby

increasing overall plant availability. Further, the majority of plant maintenance activities such as

calibration could be done from the workshop. This allowed for the reduction in reactive maintenance

but more importantly meant personal spent less time in dangerous process areas of the plant. Current

Sasol specification’s state that Foundation Fieldbus H1 is to be used on all new installations.

The 20th century brought an onslaught of a myriad of wireless protocols into the consumer market

ranging from low bandwidth protocols such as Zigbee and Bluetooth to high bandwidth protocols such

as Wireless LAN (Local Area Network) and more recently WiMAX which poses a significant threat to

the hardwired Ethernet LAN. However, adoption of wireless protocols in the process industry has

been slow an in the Sasol environment is virtually non existent. A few installations which use

rudimentary RF (Radio Frequency) technology do exist but are used for monitoring purposes only.

However, these installations represent a fraction of Sasol’s field device install base. The reason for

the lack of adoption of wireless networks is that they have been viewed as unreliable due to the

number of failure points on the network. Further, the RF band used is heavily regulated by ICASA

(Independent Communication Authority of South Africa) making installations difficult and expensive.

Over the past two years the industry leader’s namely Honeywell and Emerson have introduced a

range of wireless products to the market. Reliability issues have been addressed through the use of

self organising mesh networks which create multiple communication paths. Further, the use of the

commercial 2.4 GHz spectrum removes the necessity for ICASA approval. The wireless technologies

have the potential to significantly reduce installation costs whilst still providing the required bandwidth

demanded by the industry. However, the technology does face serious hurdles especially in

overcoming the perceptions of plant personal. At present there are no installations at Sasol which use

modern wireless standards. Figure 4 illustrates the evolution of field protocols, where performance is

measured in terms of cost and bandwidth.


Figure 4: S-Curve representation of Field Device Protocols

3.2 Technology Space Map Representation of the Companies Position with Regard to Industrial

Process Communication

Sasol Technology Control Engineering provides engineering resources to Sasol Business Units.

These resources are responsible for the implementation of Process Control Systems of which the field

device communication network forms the basis for the design, especially with regard to system

architecture.

Thus, Sasol Technology is responsible for technology selection, integration and implementation of the

field device communication network. Figure 5 below graphically represents Sasol Technology Control

Engineering’s current business area as well as that of our customers. The customers use the systems

as well as perform all maintenance related activities.

Sasol Technology’s suppliers provide the technology in terms of both hardware and software as well

as providing knowledge in the form technical recourses. The integration, selection and identification of

technologies is the responsibility of Sasol Technology. Currently research is performed by the group

in the evaluation of new trends in the industry. However, this research is restricted to information

provided by suppliers and general papers from technology institutions.

The technology space map indicates that the organisation should endeavour to develop firm links with

its clients in order understand the impacts of technology with regard to usage and maintenance. Since

the clients are part of Sasol Limited these relationships are already established but at present are not

formalised. Research related activities at present are limited with little or no practical research or

systems tests. The analysis suggests that Sasol Technology commit more resources to this area of

research in order to enhance their value contribution.


Research Design Develop Produce Maintain Use

User System

Prod. System

Product

Subsystem

Component

Material

Figure 5: Technology Space Map representing Sasol Technology Control Engineering's Position

3.3 Assessment of the Technology Readiness Level of WirelessHART

Currently the TRL system is predominantly used by the space and military institutions in U.S.A,

however, there are significant similarities between these industries and the process industry with

regard to availability and the possible loss of life due to system failures.

WirelessHART is poised to become a leading communication technology in the process industry.

Using the TRL calculator discussed earlier the technology has been evaluated in order to determine

the TRL of the technology.

In order to provide the input data for the TRL calculator interviews were carried out with senior Control

Systems Engineers from Sasol Technology. Further research data was provided by Ellender (2007)

and “Becoming Wireless” (2008)

Figure 6 provides a screenshot of the TRL calculator’s summary page. The summary suggests that

only a TRL level of 7 has been reached with a green status whilst TRL level 8 is highlighted in red

since only 2 out of the 14 criteria for TRL level 8 have been met. None of the criteria for TRL 9 have

been met.

1 2 3 4 5 6 7 8 9

Green Level Achieved

Program Manager: Muhammad SimjeeProgram Name: WirelessHART

Summary of the Technology's Readiness to Transition

Overall TRL is an aggregate TRL that includes

contributions from each one of the three readiness

level elements you have checked above.

Date TRL Calculated: 03-Apr-08

Overall TRL Achieved 7

TRL 7

Figure 6: Summary of TRL Calculator Output

Sasol Technology Control Engineering SBU

Class 1 Supplier

2009


4 Recommendations

Sasol should invest resources to enable research in the area of field level communication. This can

be established by creating test environments both in the laboratory and in non-critical areas of the

plant. Relationships with institutions which specialise in the research of these fields, need to be

established in order to ensure the quality of information provided to employees.

It is also suggested that formal investigations be established in order to evaluate the success or

failure of installations and their impact on the plant environment.

With regard to the implementation of WirelessHART, the TRL level indicates that the technology has

not reached a level of maturity where it can be implemented. However, the development of the

technology should be monitored with earnest as it has the potential to provide significant benefits to

the industry.

5 Conclusions

The technology S-curve methodology proved a valuable tool in determining the key factors which led

to the adoption of a new technology. In the process industry the driving forces for the adoption of a

new communication technology were identified as cost and bandwidth. As we progress in to the future

the wealth of information provided by field devices will undoubtedly increase thus the market demand

for bandwidth will not reduce in the near future.

Technology Space Maps can be used affectively to identify gaps in an organisations technology

strategy. The simple graphical representation provides for an effective means of communication of

technical concepts. However, in order to obtain maximum benefit from the tool a complete audit as

described by de Wet (1992) needs to be implemented in order to identify the skills and capabilities of

the employees in an organisation.

The use of the Technology Readiness Level methodology can be useful in the process industry for

evaluating various technologies. However, in order to effectively use the system both the TRL levels

and the calculator need to be modified in order to be more specific in meeting the needs of the

process industry. Aspects such as explosion protection and safety integrity level could easily be

incorporated into the evaluation thereby making the system more suitable.

There are a number of management tools available to evaluate technology and aid in forecasting, but

in order to use these tools effectively they need to be customised for the specific environment and

need to be supported with quality information.


6 References

Becoming Wireless – Case Studies and Strategise for the Wireless Plant 2008, Retrieved April 07,

2008, from www.sat-corp.com

De Wet, G 1992, Technology Space Maps for Technology Management and Audits in Management of

technology Volume 3, Institute of industrial Engineers, Norcross, pp 1235-1254.

Ellender, D 2007 , Benefits of a Digital Field Architecture for Remote Wireless Application.

Foster, R 1986, "The S-curve: A New Forecasting Tool", in The Attacker's Advantage, Summit Books,

Simon and Schuster, New York . pp. 88-111.

Mankins, JC 1995, Technology Readiness Levels , Advanced Concepts Office of Space Access and

Technology NASA. Retrieved April 2, 2008, from NASA database.

Moore, GA 1996, “Crossing the Chasm and Beyond”, in Burgelman et al., Strategic Management and

Innovation, McGraw-Hill/Irwin, New York, pp 362-368

Pretorius, MW 2001, Assessing changes in technological capability through the use of Technology

Space Maps – A South African perspective, Paper presented at the IAMOT 2001 conference in

Lausanne, Switzerland.

Tolfo, F 2004, Foundation Feildbus: Tested, Proven, Available today, European Operations Fieldbus

Foundation.

Twiss, BC 1980, “Managing Technological Innovation”, in Managing Technological Innovation,

Longman, New York, pp 206 - 234


TRL Calculator available for free download from

https://acc.dau.mil/CommunityBrowser.aspx?id=25811

United States General Accounting Office 1999, Better Management of Technology Development Can

Improve Weapon System Outcomes, GAO/NSIAD-99-162, Washington DC.


7 Appendix

Table 2: USDOD detailed description of TRL Levels

TRL Level Description

1

Lowest level of technology readiness. Research begins to be translated into

applied research and development. Examples might include paper studies of a

technology's basic properties.

2

Invention begins. Once basic principles are observed, practical applications can be

invented. Applications are speculative and there may be no proof or detailed

analysis to support the assumptions. Examples are limited to analytic studies.

3

Active research and development is initiated. This includes analytical studies and

laboratory studies to physically validate analytical predictions of separate elements

of the technology. Examples include components that are not yet integrated or

representative.

4

Basic technological components are integrated to establish that they will work

together. This is relatively "low fidelity" compared to the eventual system.

Examples include integration of "ad hoc" hardware in the laboratory.

5

Fidelity of breadboard technology increases significantly. The basic technological

components are integrated with reasonably realistic supporting elements so it can

be tested in a simulated environment. Examples include "high fidelity" laboratory

integration of components.

6

Representative model or prototype system, which is well beyond that of TRL5, is

tested in a relevant environment. Represents a major step up in a technology's

demonstrated readiness. Examples include testing a prototype in a high fidelity

laboratory environment or in simulated operational environment.

7

Prototype near or at planned operational system. Represents a major step up from

TRL6, requiring demonstration of an actual system prototype in an operational

environment, such as in aircraft, vehicle, or space. Examples include testing the

prototype in a test bed aircraft.

8

Technology proven to work in its final form and under expected conditions. In most

cases, this TRL represents the end of true system development. Examples include

developmental test and evaluation of the system in its intended weapon system to

determine if it meets specifications.

9

Actual application of the technology in its final form and under mission conditions,

such as those encountered in operational test and evaluation. Examples include

using the system under operational mission conditions.

Documents

The Past, Present and Future of Device Level Communication in the Process Control Industry