ABB SR100A User manual

ABB Instrumentation
COMMANDER SR100A
Advanced Process Recorder
COMMANDERSR100
OPERATING PAGE 1
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Operating Guide
Modbus (RTU)
Communications Option

ABB INSTRUMENTATION
✶
Note.
Clarification of an instruction or additional information.
Information.
Further reference for more detailed information or
technical details.
AlthoughWarning hazardsarerelated to personalinjury,andCaution hazardsareassociatedwithequipment orpropertydamage,
it must be understood that operation of damaged equipment could, under certain operational conditions, result in degraded
process system performance leading to personal injury or death. Therefore, comply fully with all Warning and Caution notices.
Information in this manual is intended only to assist our customers in the efficient operation of our equipment. Use of this manual
for any other purpose is specifically prohibited and its contents are not to be reproduced in full or part without prior approval of
Technical Communications Department, ABB Instrumentation.
Licensing, Trademarks and Copyrights
Modbus™ is a trademark of Modicon, Inc.
IBM™ and IBM PC AT™ are trademarks of International Business Machines Corp.
The Company
ABB Instrumentation is an established world force in the design and manufacture of
instrumentation for industrial process control, flow measurement, gas and liquid analysis and
environmental applications.
As a part of ABB, a world leader in process automation technology, we offer customers
application expertise, service and support worldwide.
We are committed to teamwork, high quality manufacturing, advanced technology and
unrivalled service and support.
The quality, accuracy and performance of the Company’s products result from over 100 years
experience, combined with a continuous program of innovative design and development to
incorporate the latest technology.
The NAMAS Calibration Laboratory No. 0255 is just one of the ten flow calibration plants
operated by the Company, and is indicative of ABB Instrumentation’s dedication to quality
and accuracy.
Stonehouse, U.K.
EN 29001 (ISO 9001)
Lenno, Italy – Cert. No. 9/90A
Use of Instructions
Warning.
An instruction that draws attention to the risk of injury or
death.
Caution.
An instruction that draws attention to the risk of damage to
the product, process or surroundings.
Health and Safety
To ensure that our products are safe and without risk to health, the following points must be noted:
1. The relevant sections of these instructions must be read carefully before proceeding.
2. Warning labels on containers and packages must be observed.
3. Installation, operation, maintenance and servicing must only be carried out by suitably trained personnel and in accordance with the
information given.
4. Normal safety precautions must be taken to avoid the possibility of an accident occurring when operating in conditions of high pressure
and/or temperature.
5. Chemicalsmustbestored awayfrom heat,protected fromtemperature extremesand powderskept dry.Normal safehandling procedures
must be used.
6. When disposing of chemicals ensure that no two chemicals are mixed.
Safety advice concerning the use of the equipment described in this manual or any relevant hazard data sheets (where applicable) may be
obtained from the Company address on the back cover, together with servicing and spares information.
0255
BS EN ISO 9001
St Neots, U.K. –Cert. No. Q5907
Stonehouse, U.K. –Cert. No. FM 21106
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1
CONTENTS
Information.
The Modbus protocol is the standard for PLC to system
communications and digital controller to PC and/or PLC
communications. It supports open communications and
provides more information with a greater degree of
interchangeabilityand connectabilityof allprocess control
and recording devices.
Section Page
1 INTRODUCTION ..........................................................2
2 ELECTRICAL INSTALLATION ....................................2
2.1 Selection of Serial Communication
Adaptors for Personal Computers........................2
2.2 Recommended OPTO22 Boards .........................2
2.3 Pull-up and Pull-down Resistors ..........................2
2.4 Termination Resistors ..........................................3
2.5 RS485/422 Standard ...........................................3
2.6 Serial Connections...............................................4
3 ADVANCED CONFIGURATION LEVEL ......................5
3.1 Serial Communication Configuration Page ..........6
4 MODBUS PROTOCOL.................................................7
4.1 Introduction to Modbus Protocol ..........................7
4.1.1 Non-volatile Memory Limitations ..........7
4.2 Modbus Function Codes ......................................8
5 MODBUS FUNCTIONS ................................................9
5.1 Read Coil Status
– Function Code 01..............................................9
5.1.1 Read Coil Status Query .......................9
5.1.2 Read Coil Status Response .................9
5.2 Read Input Status
– Function Code 02..............................................9
5.2.1 Read Input Status Query .....................9
5.2.2 Read Input Status Response .............10
5.3 Read Holding Register
– Function Code 03............................................10
5.3.1 Read Holding Register Query ............10
5.3.2 Read Holding Register Response......10
5.4 Read Input Register
– Function Code 04............................................11
5.4.1 Read Input Register Query ................11
5.4.2 Read Input Register Response .......... 11
5.5 Force Single Coil
– Function Code 05............................................12
5.5.1 Force Single Coil Query .....................12
5.5.2 Force Single Coil Response ..............12
5.6 Preset Single Register
– Function Code 06............................................13
5.6.1 Preset Single Register Query ............13
5.6.2 Preset Single Register Response ......13
5.7 Loopback Diagnostic Test
– Function Code 08............................................13
5.7.1 Loopback Diagnostic Test Query .......13
5.7.2 Loopback Diagnostic Test Response........13
5.8 Force Multiple Coils
– Function Code 15............................................14
5.8.1 Force Multiple Coils Query.................14
5.8.2 Force Multiple Coils Response ..........14
5.9 Preset Multiple Registers
– Function Code 16............................................14
5.9.1 Preset Multiple Registers Query ........14
5.9.2 Preset Multiple Registers Response ..14
5.10 User Defined
– Function Code 65............................................15
5.10.1 User Defined Query ...........................15
5.10.2 User Defined Response .....................15
Section Page
6 EXCEPTION RESPONSES........................................16
6.1 Examples ...........................................................16
7 MODBUS REGISTERS ..............................................17
7.1 Coils ...................................................................17
7.2 Inputs .................................................................18
7.3 Input Registers...................................................19
7.4 Holding Registers...............................................23
8 QUERY/RESPONSE DATA CODES ..........................24
8.1 Operator Message
Character Code Conversion ..............................24

2
Information.
• The advanced process recorder is extended by the
addition of a serial data communication option
designed for use with SCADA systems.
• RS422/485 Communication Standard.
• Modbus RTU protocol – for master (host computer) to
slave (process recorder) system.
• Isolated (500V) from rest of instrument.
• 5-wire communication supported.
• Baud rate – from 1200 to 9600.
• Parity-checking – odd, even or none.
2 ELECTRICAL INSTALLATION
1 INTRODUCTION
2.1 Selection of Serial Communication Adaptors
for Personal Computers
Information.
• A RS422/485 communication board is required in the
host PC.
• Observethe limitations outlinedin
Section7 ofthe User
Guide
. The maximum serial data transmission line
length for both RS422 and RS485 systems is 1200m.
An RS422/485 communications adaptor is required for serial
links. It is strongly recommended that the card used has
galvanic isolation to protect the computer from lightning
damage and increase immunity from noise pick-up.
2.2 Recommended OPTO22 Boards
The following OPTO22 boards are recommended for use with
the advanced process recorder:
Part No. Computer Type
AC24 AT AT Bus IBM PC compatible
AC34 Microchannel IBM PC.
2.3 Pull-up and Pull-down Resistors – Fig. 2.1
To prevent false triggering of the slave (process recorder) by
the presence of noise when the master (host computer) is
inactive, 1.8kΩpull-up and pull-down resistors must be fitted
to the RS422/485 adaptor card – see Fig. 2.1.
Fig. 2.1 Pull-up and Pull-down Resistors
1.8kΩ
Pull-up
Resistor
1.8kΩ
Pull-down
Resistor
Rx+
Rx–
Tx+
Tx–
+5V
+5V
0V
Computer Terminal or Host Computer
1
2
3
4
5
F
TB1TB2TB3TB4
6
7
8
9
10 0V
1.8kΩ
Pull-up
Resistor
1.8kΩ
Pull-down
Resistor
GND
Process Recorder

3
2.4 Termination Resistors – Fig. 2.2
Undernormaloperatingconditionstheslave termination resistors arelinkedout.Forlongtransmissionlines,termination resistors
are required on the last slave in the chain and the host computer/computer terminal – see Fig. 2.2A. The slaves termination
resistors are linked-in using plug-in link (LK1) on the serial module – see Fig. 2.2B.
2.5 RS485/422 Standard
The RS485 standard quotes connection of thirty-two slaves maximum, to any single driver (computer terminal or host computer);
theRS422 standardquotes connectionof upto ten slaves. However,thesenumbers canbe increasedif thedriver’sserial port permits.
2 ELECTRICAL INSTALLATION…
Position link
Termination
Resistors
Linked-out
Termination
Resistors
Linked-in
Identify Link
44
11
LK1LK1
Serial Module
1
4LK1
Internal Termination Resistors
C
omputer Terminal
or Host Computer
Advanced Process Recorder Slaves
Remove chassis
from case
1
2
3
Fig. 2.2 Slave Termination Resistors
Note. For long transmission lines, the internal termination resistors on the last slave in the chain must be linked-in.
A – Schematic Diagram
B – Termination Link Positions

4
2.6 Serial Connections – Fig. 2.3
Information.
• Up to 10 slaves can be connected to a single RS422 adaptor card on a PC.
• Up to 32 slaves can be connected to a single RS485 adaptor card on a PC.
• The maximum serial data transmission line length for both RS422 and RS485 systems is 1200m.
All connections, apart from those for serial data communication, are made as shown in
Section 7 of the User Guide .
Make serial data connections as shown in Fig. 2.3. The type of cable used is dependent on the cable length:
Up to 6m – standard screened or twisted pair cable
Up to 300m – twin twisted pair with overall foil screen and an integral drain wire, e.g. Belden 9502 or equivalent
Up to 1200m – twin twisted pair with separate foil screens and integral drain wires for each pair, e.g. Belden 9729 or
equivalent.
…2 ELECTRICAL INSTALLATION
Fig. 2.3 Serial Module Connections
Table 2.1 Terminal and Pin Identification
Serial Module Connections
1
2
3
4
5
F
TB1
TB2TB3TB4
6
7
8
9
10
Tx+
Tx–
Rx+
Rx–
GND
Tx+
Tx–
Rx+
Rx–
GND
OPTO22 Adaptor
Board Connections
8
5
4
9
3
Screen
Process Recorder
eludoMlaireSredroceRssecorP noitacifitnedIniPdraoB22OTPO
rebmuNlanimreTsnoitcennoC43CA&TA42CArebmuNtraPsnoitcennoC
2–XT9–XR
3+XT8+XR
5+XR4+XT
6–XR5–XT
8DNG3DNG

5
Advanced Level
Totalizer Function
Advanced Level
Enabled
Advanced Level
Serial Comms
SERIAL COMMS
CONFIGURATION
AUD RATE
PARITY
IDENTITY
asic Level
Exit
Operating Level Pages
Advanced Level
Disabled
Memory Card
Data-Logging Setup
Displayed only if Memory
Card Option fitted
3 ADVANCED CONFIGURATION LEVEL
Fig. 3.1 Location of the Serial Communication Configuration Page

6
AUD RATE
CONFIGURATION
SERIAL COMMS
PARITY
IDENTITY
9600
4800
2400
1200
ODD
EVEN
NONE
1
99
•1
•1
•1
Page Header – Serial Communication Configuration Page.
Transmission Rate
Select the transmission rate required (1200 slowest, 9600 fastest).
Parity
Select the appropriate parity to match the computer terminal or host
computer.
Identity
Assign the recorder an identification number (1 to 99). The identification
number allows more than one recorder to be accessed via the
communications channel.
Return to Serial Communication Configuration frame.
…3 ADVANCED CONFIGURATION LEVEL
3.1 Serial Communication Configuration Page
Information.
• Modbus protocol.
• Programmable baud rate (1200 to 9600 baud).
• Odd or even parity.
The general programming procedure is as detailed in the
User Guide – Section 2 .
•1 The instrument is dispatched programmed with these Company Standard Settings

7
4 MODBUS PROTOCOL
Information.
• The advanced process recorder operates as a Modbus, Remote Terminal Unit (RTU) slave.
• Parity checking – used to detect transmission errors in individual characters.
• Cyclic redundancy checking – used to detect errors in the master messages and slave responses.
• Non-volatile memory save command.
4.1 Introduction to Modbus Protocol
Modbus communication is based on a master and a slave arrangement. The master sends a message to one slave at a time and
waits for a reply.
The slave cannot accept a new message until the existing message is processed and a reply sent to the master (maximum
response time 90 milliseconds). The slave monitors the elapsed time between receipt of characters. If the elapsed time without
a new character is 31/2character times, the slave assumes the next character received is the start of a new message.
To allow the master to differentiate between more than one slave in a system, each slave is given a unique identity address
(between 1 and 99).
Abroadcast address (address zero) can be used to access all slave devices with one command. This is limited to write messages
only and there is no slave acknowledgment.
Note. Modbus RTU requires 1 start bit, 8 data bits, 1 parity bit (optional) and 1 or 2 stop bits.
4.1.1 Non-volatile Memory Limitations
Caution. If the number of write cycles to any particular non-volatile memory register exceeds 104cycles, the data
stored may not be retained.
Any changes made to a parameter via the serial link, e.g. Alarm ATrip Point value, are stored in a non-volatile memory register
assigned to that parameter.
Thenumberofwritecyclestoaparticularregistercanbereducedbydisablingnon-volatilememoryaccesswhenmakingchanges
toparameters which donotneed toberetained followingapower-down. This isachievedusing theNon-volatile Save State (NV)
Coil 061 – see Section 7.1.
When the Non-volatile Save State is set to ‘1=Saved’, any parameter changes made via the serial link are written to non-volatile
memory and are retained on power-down. If the Non-volatile Save State is set to ‘0=Not Saved’, parameter changes made via
the serial link are not retained on power down.
The Non-volatile Save State must be adjusted only when necessary and must be reset to the required state each time the
instrument is or the host computer is powered down or the instrument is replaced.

8
4.2 Modbus Function Codes
The function code field instructs the addressed slaves what function to perform. Table 4.1 shows the function codes, their
definitions, and the actions they initiate.
…4 MODBUS PROTOCOL
subdoM edoCnoitcnuF emaNegasseMsubdoM noitinifeDredroceRssecorP
10sutatSlioCdaeR .tniopgnitratscificepsamorf)slioc(stniop)naeloob(etercsidevitucesnoc61otpudaeR noitpecxenA.ataddenifedniatnoctonodhcihwstnioprofsorezsnrutertnemurtsniehT .09nahtretaergsisrebmuntnioproftseuqerynafidenrutersiesnopser
20sutatStupnIdaeR gnitratscificepsamorf)stupni(stniop)naeloob(etercsidevitucesnoc61otpudaeR dnaataddenifedniatnoctonodhcihwstnioprofsorezsnrutertnemurtsniehT.tniop .021nahtretaergsisrebmuntnioproftseuqerynafiesnopsernoitpecxenasnruter
30sretsigeRgnidloHdaeR ehT.retsigergnitratscificepsamorfsretsigergnidlohevitucesnoc21otpudaeR noitpecxenA.ataddenifedniatnoctonodhcihwsretsigermorfsorezsnrutertnemurtsni .09nahtretaergsisrebmunretsigerroftseuqerynafidenrutersiesnopser
40sretsigeRtupnIdaeR tnemurtsniehT.retsigergnitratscificepsamorfsretsigertupnievitucesnoc21otpudaeR noitpecxenasnruterdnaataddenifedniatnoctonodhcihwsretsigermorfsorezsnruter .003nahtretaergsisrebmunretsigerroftseuqerynafiesnopser
50lioCelgniSecroF fiesnopsernoitpecxenasnrutertnemurtsniehT.)lioc(tniop)naeloob(etercsidenoetirW .elbaetirwyltnerructonsitniopeht
60retsigeRelgniSteserP siretsigerehtfiesnopsernoitpecxenasnrutertnemurtsniehT.retsigergnidlohenoetirW otstimilelbacilppayltnerrucynaseilppaoslaedocnoitcnufsihT.elbaetirwyltnerructon .esabatadehtniegarotserofebeulaveht
80tseTcitsongaiDkcabpooL noitpecxenrutersedoccitsongaidrehtO.atadyreuqsnruter0000edoccitsongaidataD .sesnopser
51slioCelpitluMecroF
.tniopgnitratscificepsamorf)slioc(stniop)naeloob(etercsidevitucesnoc61otpuetirW yltnerructonerasretsigerehtfoynafiesnopsernoitpecxenasnrutertnemurtsniehT elbaliavasiedocnoitcnufehT.dilaverahcihwsetirwehtllatuoseirracllitstub,elbaetirw .16rebmunliocees–delbasidsi’yromemelitalov-nonotetirw‘fiylno
61sretsigeRelpitluMteserP
ehT.retsigergnitratsdeificepsamorfsretsigergnidlohevitucesnoc21otpuetirW yltnerructonerasretsigerehtfoynafiesnopsernoitpecxenasnrutertnemurtsni oslaedocnoitcnufsihT.dilaverahcihwsetirwehtllatuoseirracllitstub,elbaetirw ehT.esabatadehtniegarotserofebeulavehtotstimilelbacilppayltnerrucynaseilppa liocees–delbasidsi’yromemelitalov-nonotetirw‘fiylnoelbaliavasiedocnoitcnuf .16rebmun
56denifeDresU seulavnoitcnuflanretnirehtO.’noisrevtnemurtsnidaer‘ylno42noitcnuflanretnistroppuS .esnopsernoitpecxenanruter
Table 4.1 Modbus Function Codes

9
This section shows typical examples of Modbus function codes 01, 02, 03, 04, 05, 06, 08, 15, 16 and 65.
5.1 Read Coil Status –Function Code 01
5.1.1 Read Coil Status Query
This function allows the user to obtain the ON/OFF status of logic coils within the addressed slave only. Broadcast mode is not
supported with this function code. In addition to the slave address and function fields, the message requires the initial coil offset
address to be read (starting address) and the number of locations to be interrogated.
Note. The coil offset address is the coil number minus one, e.g. to start at coil 21 the data start value must be set to 20
(14H).
Example – a read coil status request to read 12 coils from slave (01) starting at coil 21 (alarm A status) is shown below.
5.1.2 Read Coil Status Response
Thedata is packedone bitforeach coil(1= active,0 = inactive).Theresponse includesthe slave address,function code, quantity
of data characters, the data characters and error checking. The low order bit of the first character contains the first addressed coil
and the remainder follow. For coil quantities that are not even multiples of eight, the last characters are filled in with zeros at high
order end.
Example – the response to the read coil status query shows the following:
Alarm A status – active
Alarm B status – acknowledged or inactive
Alarm C status – active
Alarm D status – acknowledged or inactive
Alarms E to M status – acknowledged or inactive.
5 MODBUS FUNCTIONS
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1010004100C0C7B0
sserddAnoitcnuFtnuoCetyB sutatSlioCataD 82ot12 sutatSlioCataD 63ot92 )61-CRC(dleiFkcehCrorrE
1010205000ABCA
5.2 Read Input Status –Function Code 02
5.2.1 Read Input Status Query
This function allows the user to obtain the ON/OFF status of logic inputs within the addressed slave. Broadcast mode is not
supported with this function code. In addition to the slave address and function fields, the message requires the initial input offset
address to be read (starting address) and the number of locations to be interrogated.
Note. The input offset address is the input number –1, e.g. to start at input 01 the data start value must be set to 00.
Example – a read input status request to read 16 inputs from slave (01) starting at input 01 (module A digital input 1) is shown
below.
sserddAnoitcnuF tratStupnI hgiHtesffO tratStupnI woLtesffO forebmuN hgiHstupnI forebmuN woLstupnI )61-CRC(dleiFkcehCrorrE
102000000001976C

10
5.2.2 Read Input Status Response
The data is packed one bit for each input (1 = active, 0 = inactive). The response includes the slave address, function code,
quantity of data characters, the data characters and error checking. The low order bit of the first character contains the first
addressed input and the remainder follow. For input quantities that are not even multiples of eight, the last characters are filled-
in with zeros at high order end.
Example – the response to the read input status query shows the following:
Digital input A1 – active
Digital input B1 – inactive
Digital input B2 – active
Digital input B3 – inactive
Digital inputs C1, C2, C3 – inactive
Digital inputs D1, D2, D3 – inactive
Digital inputs E1, E2, E3 – inactive
Digital inputs G1, G2, G3 – inactive
…5 MODBUS FUNCTIONS
5.3.2 Read Holding Register Response
Theaddressed slave respondswith its addressand functioncode,followed bytheinformation field.Theinformationfield contains
1 byte describing the quantity of data bytes to be returned. The contents of each register requested is two bytes, the first byte
contains the high order bits and the second the low order bits.
Example – the response to the read holding register query shows the following:
Alarm A trip point – 150
Alarm B trip point – 50
Alarm C trip point – 100
Alarm D trip point – 400
Alarm E trip point – 0
Alarm F trip point – 0.
sserddAnoitcnuF etyB tnuoC
gnidloH 15retsigeR woLhgiH gnidloH 25retsigeR woLhgiH gnidloH 35retsigeR woLhgiH gnidloH 45retsigeR woLhgiH gnidloH 55retsigeR woLhgiH gnidloH 65retsigeR woLhgiH
dleiFkcehCrorrE )61-CRC(
1030C06900230046000910000000009D19
sserddAnoitcnuFtnuoCetyB sutatStupnIataD 80ot10 sutatStupnIataD 61ot90 )61-CRC(dleiFkcehCrorrE
1020205000AB8E
5.3 Read Holding Register –Function Code 03
5.3.1 Read Holding Register Query
The Read holding registers allow the user to obtain the binary contents of holding registers in the addressed slave.
Note. The data start register must contain the offset address of the first register to be accessed, e.g. to start at register
5, the data start register must be set to 50 (32H).
Broadcast mode is not allowed.
Example – a read holding register request to read 6 holding registers from slave (01) starting at holding address 51 (alarm Atrip
point) is shown below.
sserddAnoitcnuF tratSretsigeR hgiHtesffO tratSretsigeR woLtesffO forebmuNataD hgiHsretsigeR forebmuNataD woLsretsigeR )61-CRC(dleiFkcehCrorrE
1030002300604670

11
5 MODBUS FUNCTIONS…
5.4 Read Input Register –Function Code 04
5.4.1 Read Input Register Query
The read input registers allow the user to obtain the binary contents of input registers in the addressed slave.
Note. The data start register must contain the offset address of the first register to be accessed, e.g. to start at register
01, the data start register must be set to 00.
Broadcast mode is not allowed.
Example – a read input register request to read 6 input registers from slave (01) starting at input address 01 (A1 analog input) is
shown below.
5.4.2 Read Input Register Response
Theaddressed slave respondswith its addressand functioncode,followed bytheinformation field.The information fieldcontains
1 byte describing the quantity of data bytes to be returned. The contents of each register requested is two bytes, the first byte
includes the high order bits and the second the low order bits.
Example – with an input range of 0 to 1000mV, the response to the read input register query shows the following:
A1 analog input – 200
A2 analog input – 200
A3 analog input – 200
A4 analog input – 200
A5 analog input – 200
A6 analog input – 200.
sserddAnoitcnuF tratSretsigeR hgiHtesffO tratSretsigeR woLtesffO forebmuNataD hgiHsretsigeR forebmuNataD woLsretsigeR )61-CRC(dleiFkcehCrorrE
1040000000600780
sserddAnoitcnuF etyB tnuoC
tupnI 10retsigeR woLhgiH tupnI 20retsigeR woLhgiH tupnI 30retsigeR woLhgiH tupnI 40retsigeR woLhgiH tupnI 50retsigeR woLhgiH tupnI 60retsigeR woLhgiH
dleiFkcehCrorrE )61-CRC(
1040C023302330233023302330233029AE

12
…5 MODBUS FUNCTIONS
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10500082FF00C023
sserddAnoitcnuF tesffOlioC hgiH tesffOlioC woL eulaVataD hgiH eulaVataD woL )61-CRC(dleiFkcehCrorrE
10500082FF00C023
5.5 Force Single Coil –Function Code 05
5.5.1 Force Single Coil Query
This message forces a single coil into the active or inactive state. The data value 65,280 (FF00 HEX) renders the coil active and
the value zero renders the coil inactive. All other values are illegal and do not affect the coil.
Note. To write to a coil the coil offset address must be used, e.g. to write to coil 41, the coil address 40 (28H) is
transmitted.
The use of slave address zero (broadcast mode) forces all attached slaves to modify the desired coil.
Example – a force single coil request to set coil address 41 active (print operator message command) in slave 01 is shown below.
5.5.2 Force Single Coil Response
The response is confirmation of the query after the coil state has been altered.
Example:

13
5 MODBUS FUNCTIONS…
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106000E1104F9EBD
sserddAnoitcnuF tesffOretsigeR hgiH tesffOretsigeR woL eulaVataD hgiH eulaVataD woL )61-CRC(dleiFkcehCrorrE
106000E1104F9EBD
sserddAnoitcnuF ataD citsongaiD hgiHedoC
ataD citsongaiD woLedoC ataD
* ataD * )61-CRC(dleiFkcehCrorrE
108000005A73ADD8
* .edomcitsongaidrofsdleifnoitamrofniehtebotderedisnoceraesehT
sserddAnoitcnuF ataD citsongaiD hgiHedoC
ataD citsongaiD woLedoC ataDataD)61-CRC(dleiFkcehCrorrE
108000005A73ADD8
5.6 Preset Single Register –Function Code 06
5.6.1 Preset Single Register Query
The preset single register allows the user to modify the contents of a holding register.
Note. To write to a register, the register’s offset address must be used, e.g. to write to register 31, the offset address 30
(1EH) is transmitted.
The use of slave address zero (broadcast mode) forces all attached slaves to modify the desired register.
Example – a preset single register request to write the value 500 to holding register address 31 (maths 1 constant a) in slave 01
is shown below.
5.6.2 Preset Single Register Response
The normal response to a preset single register request is to retransmit the query message after the register has been altered.
Example:
5.7 Loopback Diagnostic Test –Function Code 08
5.7.1 Loopback Diagnostic Test Query
Thepurpose oftheloopback diagnostictest isto test theModbus system,it does notaffectthe contentof the controller. Variations
in the response may indicate faults in the Modbus system. The information field contains 2 bytes for the designation of the
diagnostic code followed by 2 bytes to designate the action to be taken.
Example – a loopback test query of slave 01 is shown below.
5.7.2 Loopback Diagnostic Test Response
The response always echoes the query, only diagnostic code 0 (bytes 3 and 4) can be used.
Example:

14
…5 MODBUS FUNCTIONS
5.8 Force Multiple Coils –Function Code 15
5.8.1 Force Multiple Coils Query
Coils existing within the recorder can have their contents changed by this message (a maximum of 16 coils). When used with
slave address zero (broadcast mode) all slave controllers load the selected coils with the contents specified.
Note. To write to multiple coils, the initial coil offset address must be used, e.g. to write to coil 45 onwards, the offset
address 44 (2CH) is transmitted.
Example – a preset multiple coils request to set coil address 45 (total 1 print command) active, coil address 46 (total 2 print
command) inactive, coil address 47 (total 3 print command) active and coil address 48 (total 4 print command) active in slave 01
is shown below.
sserddAnoitcnuF tratSlioC hgiHtesffO tratSlioC woLtesffO forebmuN slioC etyB tnuoC sutatSlioC 25ot54 sutatSlioC 06ot35 )61-CRC(dleiFkcehCrorrE
10F000C2400020D0004ECE
5.8.2 Force Multiple Coils Response
The response confirms slave identification, function code, starting coil address and quantity only.
Example:
sserddAnoitcnuF tratSlioC hgiHtesffO tratSlioC woLtesffO slioCforebmuN)61-CRC(dleiFkcehCrorrE
10F000C20040591C
5.9 Preset Multiple Registers –Function Code 16
5.9.1 Preset Multiple Registers Query
Holding registers existing within the controller can have their contents changed by this message. When used with slave address
zero (broadcast mode) all slave controllers load the selected registers with the contents specified.
Note. To write to multiple registers, the initial register offset address must be used, e.g. to write to register 02 onwards,
the offset address 01 is transmitted.
Example – a preset multiple registers request to write the value 10 to the register address 02 (chart speed 1) and the value 100
to the register address 03 (chart speed 2) in slave 01 is shown below.
sserddAnoitcnuF
retsigeR tratS tesffO hgiH retsigeR tratS tesffO woL
forebmuN sretsigeR etyB tnuoC
gnidloH retsigeR hgiH20 gnidloH retsigeR woL20 gnidloH retsigeR hgiH30 gnidloH retsigeR woL30
dleiFkcehCrorrE )61-CRC(
1001001020004000A0004631A8
sserddAnoitcnuF tratSretsigeR hgiHtesffO tratSretsigeR woLtesffO sretsigeRforebmuN)61-CRC(dleiFkcehCrorrE
1001001000200180
5.9.2 Preset Multiple Registers Response
The response confirms slave identification, function code, starting register address and quantity only.
Example:

15
5 MODBUS FUNCTIONS
sserddAnoitcnuFlortnoCnoitcnuFlanretnIreifilauQtnuoCetyB)61-CRC(dleiFkcehCrorrE
101490810000EBE5
sserddAnoitcnuFlortnoCtnuoCetyBataD)61-CRC(dleiFkcehCrorrE
101490D0020202020203E21302020202655F6F
5.10 User Defined –Function Code 65
5.10.1 User Defined Query
The user defined function makes available to the user a range of non-standard Modbus query responses. The information field
comprisesof a controlbyte which defines control type,an internal function byte designatingthe action tobe taken,a qualifier byte
the usage of which is dependent on the user defined task and a byte specifying the number of bytes to follow in the information
data string.
Example – a user defined read instrument version (internal function 24) of slave 01 is shown below.
The control byte has no effect, valid qualifier and byte counts are zero only and other values return an exception response.
5.10.2 User Defined Response
The addressed slave responds with its address and function code followed by the information field. The information field
comprises of the control byte, one byte defining the quantity of data bytes in the response information string and the data string.
Example:

16
6 EXCEPTION RESPONSES
noitpecxE edoCesnopseR emaNesnopseRnoitpecxE noitinifeDesnopseRnoitpecxE
10noitcnuFlagellI .tnemurtsniehtrofnoitcaelbawollanatonsideviecernoitcnufegassemehT
20sserddAataDlagellI .tnemurtsniehtrofsserddaelbawollanatonsidleifatadehtniecnerefersserddaehT
30eulaVataDlagellI .noitacolevalsdesserddaehtnielbawollatonsidleifatadehtnidecnerefereulavehT
40eciveDdetaicossAnieruliaF .evalsnirorreevitroba,yltcerrocdnopserotelbanU
70tnemgdelwonkcAevitageN.rorreegassemdevieceR
80rorrEytiraPyromeM .deviecersretcarahcehtfoeromroenonirorrenasetacidnikcehcytiraP
sserddAevalSnoitcnuF tratSretsigeR hgiHtesffO tratSretsigeR woLtesffO forebmuN hgiHsretsigeR forebmuN woLsretsigeR )61-CRC(dleiFkcehCrorrE
103000A500605EBD
sserddAevalSnoitcnuFedoCnoitpecxE)61-CRC(dleiFkcehCrorrE
103820OC1F
The exception response codes sent by the slave are shown in Table 6.1. When a slave detects one of these errors, it sends a
response message to the master consisting of slave address, function code, error code and error check fields.
Table 6.1 Exception Response Codes
6.1 Examples
A read register request to read holding register address 91 of slave 01 (undefined address for slave, beyond address limit) is
shown below.
The response is an exception response sighting ‘illegal data address’. To indicate that the response is a notification of an error,
the most significant bit of the function code is set to 1.

17
7 MODBUS REGISTERS
Coil Number Read/Write Description Response Entry
Totalizer Settings
001 R/W Totalizer 1 Stop/Go
002 R/W Totalizer 2 Stop/Go
003 R/W Totalizer 3 Stop/Go 0 = Stop
004 R/W Totalizer 4 Stop/Go 1 = Go
005 R/W Totalizer 5 Stop/Go
006 R/W Totalizer 6 Stop/Go
007 W Totalizer 1 Reset
008 W Totalizer 2 Reset
009 W Totalizer 3 Reset 0 = Inactive
010 W Totalizer 4 Reset 1 = Reset to Preset Value
011 W Totalizer 5 Reset
012 W Totalizer 6 Reset
Alarm Status
021 R/W Alarm A
022 R/W Alarm B
023 R/W Alarm C
024 R/W Alarm D
025 R/W Alarm E
026 R/W Alarm F
027 R/W Alarm G
028 R/W Alarm H 0 = Alarm State Acknowledged or Inactive
029 R/W Alarm J 1 = Alarm State Active Not Acknowledged
030 R/W Alarm K
031 R/W Alarm L
032 R/W Alarm M
033 R/W Real Time Alarm 1
034 R/W Real Time Alarm 2
035 R/W Line (Power) Fail
Print Commands
041 W Print Operator Message
042 W Print Channel Data
043 W Print Channel Values
044 W All Totals Print
045 W Total 1 Print
046 W Total 2 Print
047 W Total 3 Print
048 W Total 4 Print 0 = Inactive
049 W Total 5 Print 1 = Active
050 W Total 6 Print
051 W Scale 1 Print
052 W Scale 2 Print
053 W Scale 3 Print
054 W Scale 4 Print
055 W Scale 5 Print
056 W Scale 6 Print
Memory Access Commands
061 R/W Non-volatile Save State* 0 = Not Saved, 1 = Saved
*See Section 4.1.1
7.1 Coils

18
…7 MODBUS REGISTRATIONS
Continued…
Input Number Read/Write Description Response Entry
Digital Input State
001 R Digital Input A1
002 R Digital Input B1
003 R Digital Input B2
004 R Digital Input B3
005 R Digital Input C1
006 R Digital Input C2
007 R Digital Input C3
008 R Digital Input D1 0 = Inactive
009 R Digital Input D2 1 = Active
010 R Digital Input D3
011 R Digital Input E1
012 R Digital Input E2
013 R Digital Input E3
014 R Digital Input G1
015 R Digital Input G2
016 R Digital Input G3
Analog Input Fail States
031 R A1 Fail State
032 R A2 Fail State
033 R A3 Fail State
034 R A4 Fail State
035 R A5 Fail State
036 R A6 Fail State 0 = Inactive
037 R B1 Fail State 1 = Active
038 R B2 Fail State
039 R B3 Fail State
040 R B4 Fail State
041 R B5 Fail State
042 R B6 Fail State
Alarm States
051 R Alarm A
052 R Alarm B
053 R Alarm C
054 R Alarm D
055 R Alarm E
056 R Alarm F
057 R Alarm G 0 = Inactive
058 R Alarm H 1 = Active
059 R Alarm J
060 R Alarm K
061 R Alarm L
062 R Alarm M
063 R Real Time Alarm 1
064 R Real Time Alarm 2
7.2 Inputs