ARAMCO DeLaval Turbines DCS/Governor/Drive Serial Link ...lovejoycontrols.com/aramco/DCS_COMM.pdf · ARAMCO DeLaval Turbines DCS/Governor/Drive Serial Link Specification Page 6 Lovejoy

ARAMCO DeLaval Turbines DCS/Governor/Drive Serial Link Specification Page 1Lovejoy Controls Corporation

ARAMCO PO No. 4503210485Document Control

Version Description Date By

0 Initial Release WIP 11/5/10 KAL/BKC

Background

This document provides details for establishing and testing a serial communications link betweenthe Woodward 505 Governor in primary service and the plant Distributed Control System (DCS). Specific message polling details are defined to avoid ambiguity.

Index

1.0 Hardware and Software Protocol Page 2

2.0 DCS Serial Port Rest rictions Page 2

3.0 Generic Data Polling Instructions Page 4

4.0 Recommended Data Set Polling, Governors Page 11

5.0 Recommended Data Set Polling, Servo Drive Page 19

6.0 Recommended Data Set Polling, Overspeed Units Page 23

7.0 Recommended DCS Control Screens Page 25

8.0 Combined Query Polling Diagram Page 26-27


1.0 Hardware and Software Protocol

____ 1.1 RS-485 Multidrop

____ 1.2 ModBus RTU

____ 1.3 DCS = Master, Governors = Slaves

____ 1.4 Slave IDs: 11 = Governor 1 12 = Governor 2 13 = Servo Drive

____ 1.5 Baud Rate = 19200

____ 1.6 8 Data Bits, No Parity, 1 Stop Bit

2.0 DCS Serial Port Restrictions

____ 2.1 The RS-485 Port Must Be Multidrop Compatible... It must be capable ofaddressing the required ModBus RTU queries (Section 3.0) to the threeassigned slave code drops.

____ 2.2 >1.5-Character Dead Time Identifies End-of-Message... Therefore theDCS serial port must provide continuous message streams which are notinterrupted. False gaps or delays in messages greater than 1.5 characterframes (0.78 milliseconds at 19200 BAUD) will result in loss ofcommunications and data transfer problems.


3.0 Generic Data Polling Instructions

3.1 Read Digital Input Status Code 01 (Read Commands)

Command status is read by the DCS poll of the slave drops using the ModBusRTU Function Code 01 (Read Discrete Outputs). All DCS queries are to use thefollowing query transmit and response receive formats:

DCS QUERY and TARGET SLAVE RESPONSE

DCS QUERY SLAVE RESPONSE

Byte No. Content Byte No. Content

1 Slave Drop Code 1 Slave Drop Code

2 Function Code = 02 2 Function Code = 02

3 Starting Address HI 3 Byte Count = BC

4 Starting Address LO 4 Data Byte 1

5 No. of Points HI 5 Data Byte 2

6 No. Points LO ... continues until all requested inputs areprovided in consecutive bytes.

7 CRC HI BC + 4 CRC HI

8 CRC LO BC + 5 CRC LO


3.2 Read Digital Input Status Code 02 (Read Alarms and Indications)

Alarm and Indicator status is read by the DCS poll of the slave drops using theModBus RTU Function Code 02 (Read Discrete Inputs). All DCS queries are touse the following query transmit and response receive formats:







4 Starting Address LO 4 Data Byte 1

5 No. of Points HI 5 Data Byte 2

6 No. Points LO ... continues until all requested inputs areprovided in consecutive bytes.

7 CRC HI BC + 4 CRC HI

8 CRC LO BC + 5 CRC LO


3.3 Read Holding Registers Code 03 (Data Input Values)

Data input values are read by the DCS poll of the slave drops using the ModBusRTU Function Code 03 (Read Multiple Input Registers). All DCS queries are touse the following query transmit and response receive formats.







4 Starting Address LO 4 First Data HI

5 No. of Points HI 5 First Data LO

6 No. of Points LO 6 Second Data HI

7 CRC HI 7 Second Data LO

8 CRC LO ...continues until all requested data areprovided in consecutive pairs (HI/LO) ofbytes

BC + 4 CRC HI

BC + 5 CRC LO


3.4 Read Holding Registers Code 04, (Data Output Values)

Data output values are read by the DCS poll of the slave drops using the ModBusRTU Function Code 04 (Read Multiple Output Registers). All DCS queries are touse the following query transmit and response receive formats.







4 Starting Address LO 4 First Data HI

5 No. of Points HI 5 First Data LO

6 No. of Points LO 6 Second Data HI

7 CRC HI 7 Second Data LO

8 CRC LO ...continues until all requested data areprovided in consecutive pairs (HI/LO) ofbytes

BC + 4 CRC HI

BC + 5 CRC LO


3.5 Write Single Discrete Output, Code 05 (Force Coil)

Coil values (digital discrete) are forced by the DCS write to the slave drop usingthe ModBus RTU 05 (Single Coil Force) function code. All DCS queries are touse the following query transmit and response receive formats.






3 Starting Address HI 3 Starting Address HI

4 Start ing Address LO 4 Starting Address LO

5 Force Data HIFF = on 00 = off

5 Force Data HIFF = on 00 = off

6 Force Data LO00 = on 00 = off

6 Force Data LO00 = on 00 = off

7 CRC HI 7 CRC HI

8 CRC LO 8 CRC LO


3.6 Write Single Holding Register, Code 06 (Single Setpoint Entry)

One Holding Register is written by the DCS to the slave drop using the ModBus RTU 06(Single Holding Register Write) function code 06. All DCS queries are to use thefollowing query transmit and response receive formats.






3 Register Address HI 3 Register Address HI

4 Register Address LO 4 Register Address LO

5 Data HI 5 Data HI

6 Data LO 6 Data LO

7 CRC HI 7 CRC HI

8 CRC LO 8 CRC LO


3.7 Write Multiple Digital Outputs, Code 15 (Multiple Command Write)

Multiple Digital Output values (digital discrete) are forced by the DCS write to theslave drop using the ModBus RTU 15 (Multiple Coil Force) funct ion code. AllDCS queries are to use the following query transmit and response receive formats.








5 No. of Coils HI 5 No. of Coils HI

6 No. of Coils LO 6 No. of Coils LO

7 Byte Count = BC 7 CRC HI

8 Force Data #1 8 CRC LO

...continues until all Force Coilvalues are provided for a total of modulo 8(BC).

8+mod8(BC)

CRC HI

9+mod8(BC)

CRC LO


3.8 Write Multiple Holding Registers, Code 16 (Multiple Parameter Write)

Multiple Holding Registers are written by the DCS to the slave drop using theModBus RTU (Multiple Holding Register Write) function code 16. All DCSqueries are to use the following query transmit and response receive formats.








5 No. of Registers HI 5 No. of Registers HI

6 No. of Registers LO 6 No. of Registers LO

7 Byte Count = BC 7 CRC HI

8 Data #1 HI 8 CRC LO

...continues until all Register Datavalues are provided.

8+ BC CRC HI

9+ BC CRC LO


4.0 Recommended Data Set Polling, Governors

The Woodward 505 Governor permits DCS ModBus RTU Port serial queries to initiatecontrol commands, read control status and alarms, and read operating parameters. This sectionprovides the recommended specific polling sequence for expeditious functioning of the governor. Please note that standard ModBus RTU protocol requires a minimum of 3.5 Character, 1.83millisecond Delay between message queries on the network regardless of slave destination.

4.1 Routine Background Queries

These queries should be performed on a regular period of one (1) second intervalto update DCS control screen elements with the latest governor-in-control status. Recommended control screen layouts are provided in Section 7.0. The updatedata is used in two types of tasks:

> Display indicators are turned ON or OFF and target buttonacknowledge fields are ACTIVE or INACTIVE. Governor Coilsare read for this information. In the case of alarm, trip, and statusinformation a time/date stamped log entry including descriptionshould be made on each Change of State (COS) for futurereference, and an assigned indicator should be ON/OFF for coilstatus of SET/CLEAR.

> Displayed numerical values are updated with the latest governordata. Governor Holding Registers are read for this information.

Since not all of the Woodward Governor data is implemented in this applicationthe full data sets are not read. Only data pertinent to the governor controls used isqueried.


4.1.1 Read Digital Input Status Coil for Determining Governor In Control (USEFORMAT 3.2)

Slave Address: 01Command Code: 02Starting Address: 152Number of Coils: 1

Data Display:

Coil Address Description Device DCS Task Notes

1.0153 Governor In ControlConfirmation Relay #1

GOV 1I-C Ind

GOV 2I-C Ind

Assign act ive fieldcolor when set,inactive when clear

Assign act ive fieldcolor when clear,inactive when set.

Log on COS.

*NOTE: The value of Coil Address 1.0153, "Relay #1 Status" determines the In ControlGovernor Unit designation. If the Relay #1 status is SET (=1), the polledGovernor #1 is the In Control Governor and Governor #2 is the TrackingGovernor. If the Relay #1 status is CLEAR (=0), the polled Governor #1 is theTracking Governor and Governor #2 is the In-Control Governor.

4.1.2 Read Digital Input Status Coil of Governor In Control for Tracking GovernorStatus (USE FORMAT 3.2)

Slave Address: Previously Determined Governor in Control*Command Code: 02Starting Address: 238Number of Coils: 1


1.0239 Tracking GovernorAvailable

TRKGOVOK Ind



4.1.3 Read Digital Input Status Coils of Governor In Control (USE FORMAT 3.1)Slave Address: Previously Determined Governor in Control*Command Code: 01Starting Address: 01Number of Coils: 16

DCS Data/Display Updates: All Devices are DCS Screen Target ButtonIndicators.


0.0002 Governor EmergencyShutdown Acknowledge

GovESD

Assign acknowledgefield color when set.

0.0003 Governor ControlledShutdown

GovCSD


0.0005 Governor Reset GovRST


0.0006 Governor Run GovRUN


0.0017 DCS Speed Control Mode GovDCS


4.1.4 Read Alarm & Operating Status Coils (USE FORMAT 3.2)Slave Address: Previously Determined Governor in Control*Command Code: 02Starting Address: 00Number of Coils: 81

Data/Display Updates:



1.0001 Alarm - MPU #1 Failed GOVMPU#1 Ind

Log on COS, MPU #1Indicator ON/OFF

1.0002 Alarm - MPU #2 Failed GOVMPU#2 Ind

Log on COS, MPU #2Indicator ON/OFF

1.0012 Alarm - Actuator Failed GOVACTInd

Log on COS, ACTIndicator ON/OFF

1.0014 Alarm - Start PermissiveNot Met

GOVS/UInd


1.0018 Alarm - Turbine Trip GOVTRPInd


1.0020 Alarm - Overspeed GOVOSPInd


1.0041 Trip - External GOVETRPInd


1.0042 Trip - ESD Button GOVESDBInd


1.0043 Trip - Overspeed GOVOSPTInd


1.0044 Trip - Loss of SpeedSignals

GOVSSLTInd


1.0045 Trip - Actuator Fault GOVAFTInd



1.0064 Trip - Trip Condition GOVTRPInd


1.0076 Status - Speed in PIDControl

GOVPIDInd


1.0077 Status - Speed Sensor 1Fail Override

GOVSP1FInd


1.0078 Status - Speed Sensor 2Fail Override

GOVSP2FInd


1.0079 Status - Overspeed TestPermissive

GOVOTPInd


1.0080 Status - Overspeed TestIn Progress

GOVOTAInd


1.0081 Status - Speed At orAbove Min Gov

GOVMinInd


4.1.5 Read Operating Input Parameters (USE FORMAT 3.3)Slave Address: Previously Determined Governor in Control*Command Code: 03Starting Address: 00Number of Registers: 1


HoldingRegisterAddress

Description Device DCS Task Notes

4.0001 Accepted DCS SpeedSetpoint. Integer Value

GOVDCSSP

Update "GovernorAccepted SpeedSetpoint" 4-digit RPM


4.1.6 Read Operating Output Parameters (USE FORMAT 3.4)Slave Address: Previously Determined Governor in Control*Command Code: 04Starting Address: 00Number of Registers: 49




3.0004 Turbine Speed, IntegerRPM

TURBSPD

Update "GovernorTurbine Speed" 4-digitRPM Display

3.0007 Governor Turbine SpeedSetpoint, Integer RPM

GOVSP

Update "GovernorSetpoint Speed" 4-digit RPM Display

3.0011 Governor Minimum SpeedSetpoint, Integer RPM

GOVMINSPD

Update "GovernorMinimum Speed" DataValue

3.0014 Governor MaximumSpeed Setpoint, IntegerRPM

GOVMAXSPD

Update "GovernorMaximum Speed"Data Value

3.0049 Governor ActuatorPercent Demand, x 100

GOVACTDEM%

Update "GovernorActuator DemandPercent" Display

4.1.7 Execute Background Commands for Other Slave Drops (Servo Drive Section 5.0and Overspeed Monitors Section 6.0), then repeat 4.1.1 in 1.0 elapsed secondsfrom previous cycle.


4.2 Command Sequence Queries

These queries should be performed on demand, injected after completion of thecurrent routine query and the required delay as actions following operatorworkstation screen commands or DCS Processed Value Assignments. Each queryresults in a write of a single coil or single holding register to the governor from theDCS. The correct slave response should be tested and additional confirmationquery should be issued when and as specified.

The DCS Control Screen Target Buttons will have three display states:

a. Command.. . The operator has selected and touched the button.b. Acknowledge Active...The Governor-In-Control has acknowledged the

implemented commandc. Inactive... The Governor-In-Control reports the command inactive.

4.2.1 Governor Shutdown Button Target, USE FORMAT 3.5 (p7)Slave Address: Previously Determined Governor in ControlCommand Code: 05Address: 00Force Data HI: FFForce Data LO: 00

4.2.2 Governor RESET Button Target, USE FORMAT 3.5 (p7)Slave Address: Previously Determined Governor in ControlCommand Code: 05Address: 04Force Data HI: FFForce Data LO: 00

4.2.3 Governor RUN Button Target, USE FORMAT 3.5 (p7)Slave Address: Previously Determined Governor in ControlCommand Code: 05Address: 05Force Data HI: FFForce Data LO: 00


4.2.4 Governor SPEED SETPOINT Valuation, USE FORMAT 3.6 (p8)Slave Address: Previously Determined Governor in ControlCommand Code: 06Address: 00Data: DCS Speed Setpoint Demand Integer, RPM

4.3 DCS Alarm and Status Processing

As previously suggested, the DCS should process Alarm and Status informationboth to individual "Tag Board" indicators and to a historical Log which includestime and date stamp for future reference. Conventions for each task are providedin the following:

4.3.1 "Tag Board" Alarm Indicators

In keeping with other DCS alarm indication standards, DCS governor alarmindicators should further have three operating states:

4.3.1.a Steady-ON... when a previous ACTIVE alarm state has beenacknowledged and no change of state has occurred since the lastacknowledge.

4.3.1.b Steady-OFF... when a previous INACTIVE alarm state has beenacknowledged and no change of state has occurred since the lastacknowledge.

4.3.1.c Flashing ON/OFF... when a change of status (COS) has occurred(either to ACTIVE or to INACTIVE) since the last acknowledge.

4.3.2 Alarm Acknowledge Target Function

The alarm acknowledge target button should induce an internal DCS task, not agovernor query. The internal task is defined as placing any alarm indicators ONwhich have ACTIVE alarms, and turning any alarm indicators OFF which haveINACTIVE alarms. Thus, after the alarm acknowledge task is performed, noindicators should remain in the flashing state (until a subsequent COS is receivedby query/response).

The resulting logic provides that any alarm indicator which has changed state willflash to alert the operator. Once acknowledged, the indicator is on in alarm andoff if inactive.


5.0 Recommended Data Set Polling, Servo Drive

The Emerson CT Unidrive SP3401 DCS ModBus RTU Port serial queries to read controlstatus and alarms, and read operating parameters. This section provides the recommendedspecific polling sequence for expeditious functioning of the servo drive. Please note that standardModBus RTU protocol requires a minimum of 3.5 Character, 1.83 millisecond Delay betweenmessage queries on the network regardless of slave destination.


These queries should be performed on a regular period to update DCS controlscreen elements with the latest servo drive status. Recommended control screenlayouts are provided in Section 7.0. The update data is used in two types of tasks:

> Display indicators are turned ON or OFF. Servo holding registersare read for this information. In the case of alarm, trip, and statusinformation a time/date stamped log entry including descriptionshould be made on each Change of State (COS) for futurereference, and an assigned indicator should be ON/OFF for alarmholding register status of 1 (SET) or 0 (CLEAR).

> Displayed numerical values are updated with the latest servo drivedata. Holding Registers are read for this information.

Only data pertinent to this application of the servo drive used is queried.


5.1.1 Read Holding Registers Determining Alarms (USE FORMAT 3.3)Slave Address: 06Command Code: 03Starting Address: 1014Number of bytes: 4

Data Display:


Description DCS Task Notes

4:1015 Mains Loss If value = 1, updateServo Drive PowerLoss alarm indicator,otherwise clear alarmindicator

4:1016 Under Voltage Active If value = 1, updateServo Drive UnderVoltage alarmindicator, otherwiseclear alarm indicator

1016 Overload Alarm If value = 1, updateServo Drive Overloadalarm indicator,otherwise clear alarmindicator

1017 Drive Over TemperatureAlarm

If value = 1, updateServo Drive OverTemperature alarmindicator, otherwiseclear alarm indicator.This variable shouldbe logically OR-edwith 1816 below


5.1.2 Read Holding Registers for Data and more Alarms (USE FORMAT 3.3)Slave Address: 06Command Code: 03Starting Address: 1812Number of bytes: 9

Data Display:



4:1813 - 1814 Position Feedback Update Actuatorposition percentdisplay. Holdingregister value 0 to4095 = 0 to 100%.

4:1815 Drive Enable Status If value = 1, assignactive field color when value=0 assign,inactive field color forservo drive enabled.

4:1816 unused unused at this time

4:1817 EZ Motion moduleoverheat ACtive

If value = 1, updateServo Drive OverTemperature alarmindicator, otherwiseclear alarm indicator.This variable shouldbe logically OR-edwith 1017 above.

4:1818 Stack Temperature Update Servo Drivetemperature display. Holding Register valueis degrees C.


4:1819 Output Short Active If value = 1, updateServo Drive OutputShort alarm indicator,otherwise clear alarmindicator

4:1820 Drive Trip Active If value = 1, the ServoDrive has tripped andis no longer sendingcurrent to the motor. Alarm indicatorsshould be activated toinitiate a turbine trip. If value = 0, no servodrive trip conditionexists.

4:1821 Following Error Active If value = 1, updateAlarm indicator toactive state for ServoDrive FollowingError. If value = 0,set alarm indicator toinactive state.

5.1.3 Read Holding Registers for Current Output (USE FORMAT 3.3)Slave Address: 06Command Code: 03Starting Address: 400Number of bytes: 1

Data Display:



4:0401 Active Current Update ActuatorMotor CurrentHolding register value= drive current. Canbe ±. Value give to 2decimal places.


6.0 Recommended Data Set Polling, Overspeed Units

The Woodward ProTech-GII ModBus RTU Port serial queries to read control status andalarms, and read operat ing parameters. This section provides the recommended specific pollingsequence for expeditious functioning of the overspeed units. Please note that standard ModBusRTU protocol requires a minimum of 3.5 Character, 1.83 millisecond Delay between messagequeries on the network regardless of slave destination.


These queries should be performed on a regular period to update DCS controlscreen elements with the latest servo drive status. Recommended control screenlayouts are provided in Section 7.0. The update data is used in two types of tasks:

> Display indicators are turned ON or OFF. ProTech BooleanAddress registers are read for this information. In the case ofalarm, trip, and status information a time/date stamped log entryincluding description should be made on each Change of State(COS) for future reference, and an assigned indicator should beON/OFF for alarm holding register status of 1 (SET) or 0(CLEAR).

> Displayed numerical values are updated with the latest ProTechmodule data. Holding Registers are read for this information.

Only data pertinent to this application of the ProTech-GII used is queried

6.1.1 Read Boolean Address for Overspeed Trip (USE FORMAT 3.2)Slave Address: 03, 04, 05Command Code: 02Starting Address: 04Number of Coils: 1

Data Display:



1:0005 OverspeedTrip

OPD OVER-SPEED

Value = 1 forOverspeed Trip


6.1.2 Read Boolean Addresses for Status (USE FORMAT 3.2)Slave Address: 03, 04, 05Command Code: 02Starting Address: 200Number to Read: 5

Data Display:



1:0201 InternalFaultAlarm

OPD FAULT


1:0202 ModuleConfigMismatchAlarm

OPDMODULEMISMATCH


1:0203 PowerSupply 1FaultAlarm

OPD PWRSUPPLY 1


1:0204 PowerSupply 2FaultAlarm

OPD PWRSUPPLY 2


1:0205 Speed FailAlarm

OPDSPEEDPROBE



6.1.3 Read Holding Registers for Speed (USE FORMAT 3.4)Slave Address: 03, 04, 05Command Code: 04Starting Address: 0Number of Registers: 1

Data Display:



3:0001 SPEED OPD RPM

Update "OPD" 4-digitRPM Display

7.0 Recommended DCS Control Screens

The workstation control screens should utilize the same conventions and formats as otherDCS control applications in use. Display objects require fit into three categories:

7.1 Numerical Displays

Holding register data is often displayed in engineering units with the image of a"digital meter" for operators. Some useful features in numerical data display are:

7.1.1 Data which has not been recently refreshed should display the last knowngood value but in a "grayed-out", masked, or other visual technique to alertoperators that the data is stale.

7.1.2 Data need not be updated quicker than the ModBus polling time of 1 Hz.

7.1.3 Historical plot availability of data values over the past several hours areuseful to operators in analyzing trends.

7.1.4 Suggested data is the listed holding register data in this document for thegovernor, servo drive, and overspeed monitor.

7.2 Indicators

Indicators group into two types, Alarm and Status.


7.2.1 Alarm indicators should be listed in "tag-board" style and bunched into acommon screen area. The three-state (ON/OFF/FLASH) logic withAcknowledge Target is recommended as previously described.

7.2.2 Status indicators are two state (ON/OFF) to provide operators with digitalpoint information.

7.2.3 Both Alarms and Status should be logged as descriptors plus time/datestamp in a History Log for subsequent review.

7.2.4 All alarms and status listed in the governor, servo drive, and overspeedmonitor should be presented.

7.3 Targets (Buttons)

Targets provide means for operators to initiate ModBus commands to thegovernors and other network drops from the workstation screens. All commandsas listed in the governor, servo drive, and overspeed monitor should be presented.A DCS evaluation of the query response should be provided to indicate anacknowledged command.

7.4 The LCC DCS Simulator

As a required test instrument, LCC will prepare a PC-based ModBus RTUcommunications program and control screens to simulate the DCS for the FactoryAcceptance Tests (FAT). When completed and sorted with the slave drops, thisprogram will be made available in open format for the assistance of the DCSscreen developer.

8.0 Combined Query Polling Diagram

The diagram on the next page illustrates the polling technique recommended on theModBus RTU protocol RS-485 network. More specific details may be found in the FATDCS Simulator Program.


Polling Diagram

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ARAMCO DeLaval Turbines DCS/Governor/Drive Serial Link ...lovejoycontrols.com/aramco/DCS_COMM.pdf · ARAMCO DeLaval Turbines DCS/Governor/Drive Serial Link Specification Page 6 Lovejoy