YOKOGAWA IR202 User manual

User’s
Manual Model IR202
Infrared Gas Analyzer
Communication Functions
(MODBUS)
IM 11G02Q02-51EN
IM 11G02Q02-51EN
2nd Edition

i
<PREFACE>
IM 11G02Q02-51EN 2nd Edition : Sep. 04, 2020-00
uPREFACE
We are grateful for your purchase of Yokogawa’s Infrared Gas Analyzer, Model: IR202. Read this
instruction manual carefully.
The document numbers of related documents are as follows.The “EN” in the document number
is the language code, meaning English.
GeneralSpecications:GS11G02Q02-01EN
User’s Manual: IM 11G02Q02-01EN
IM 11G02Q02-51EN Communication Functions (MODBUS)
(This manual)
IM 11G00E01-01EN ZX8D Zirconia Oxygen Analyzer
Media No.IM 11G02Q02-51EN 2nd Edition :Sep. 2020 (YK)
All Rights Reserved Copyright © 2017, Yokogawa Electric Corporation

ii
<PREFACE>
IM 11G02Q02-51EN 2nd Edition : Sep. 04, 2020-00
uSafety Precautions
nSafety,Protection,andModicationoftheProduct
• In order to protect the system controlled by the product and the product itself and ensure
safe operation, observe the safety precautions described in this user’s manual. We assume
no liability for safety if users fail to observe these instructions when operating the product.
• Ifthisproductisusedinamannernotspeciedinthisuser’smanual,theprotection
provided by this product may be impaired.
• If any protection or safety circuit is required for the system controlled by the product or for
the product itself, prepare it separately.
• Be sure to use the spare parts approved by Yokogawa Electric Corporation (hereafter
simply referred to as YOKOGAWA) when replacing parts or consumables.
• Modicationoftheproductisstrictlyprohibited.
• The following safety symbols are used on the product as well as in this manual.
WARNING
This symbol indicates that an operator must follow the instructions laid out in this manual in
order to avoid the risks for the human body and health including risk of injury, electric shock, or
fatalities. or the damages to products. The manual describes what special care the operator must
take to avoid such risks.
CAUTION
This symbol indicates that the operator must refer to the instructions in this manual in order
to prevent the product (hardware) or software from being damaged, or a system failure from
occurring.
The following are signal words to be found only in our instruction manuals.
CAUTION
This symbol gives information essential for understanding the operations and functions.
NOTE
This symbol indicates information that complements the present topic.
nNotes on Handling User’s Manuals
• Please hand over the user’s manuals to your end users so that they can keep the user’s
manuals on hand for convenient reference.
• Please read the information thoroughly before using the product.
• The purpose of these user’s manuals is not to warrant that the product is well suited to any
particular purpose but rather to describe the functional details of the product.
• No part of the user’s manuals may be transferred or reproduced without prior written
consent from YOKOGAWA.
• YOKOGAWA reserves the right to make improvements in the user’s manuals and product at
any time, without notice or obligation.
• Ifyouhaveanyquestions,oryoundmistakesoromissionsintheuser’smanuals,please
contact our sales representative or your local distributor.

iii
<PREFACE>
IM 11G02Q02-51EN 2nd Edition : Sep. 04, 2020-00
nDrawing Conventions
Somedrawingsmaybepartiallyemphasized,simplied,oromitted,fortheconvenienceof
description.
Somescreenimagesdepictedintheuser’smanualmayhavedi󰀨erentdisplaypositionsor
character types (e.g., the upper / lower case). Also note that some of the images contained in this
user’s manual are display examples.
n AuthorizedRepresentativeinEEA
The Authorized Representative for this product in EEA is Yokogawa Europe B.V. (Euroweg 2,
3825 HD Amersfoort, The Netherlands).
n Trademarkpolicy
• All names of company, brand of product used in this manual are registered trademarks.
• TM or ® to signify brand or trademarks are not used in this manual.

iv
<PREFACE>
IM 11G02Q02-51EN 2nd Edition : Sep. 04, 2020-00
uAfter-Sales Warranty
 Donotmodifytheproduct.
 Yokogawawarrantstheproductfortheperiodstatedinthepre-purchase
quotation.Yokogawashallconductdenedwarrantyservicebasedonits
standard.Whenthecustomersiteislocatedoutsideoftheservicearea,afee
fordispatchingthemaintenanceengineerwillbechangedtothecustomer.
 Duringthewarrantyperiod,forrepairunderwarrantycarryorsendtheproduct
tothelocalsalesrepresentativeorserviceo󰀩ce.Yokogawawillreplaceor
repairanydamagedpartsandreturntheproducttoyou.
Before returning a product for repair under warranty, provide us with the model name
and serial number and a description of the problem. Any diagrams or data explaining the
problem would also be appreciated.
If we replace the product with a new one, we won’t provide you with a repair report.
 Inthefollowingcases,customerwillbechargedrepairfeeregardlessof
warrantyperiod.
Failure of components which are out of scope of warranty stated in instruction manual.
Failure caused by usage of software, hardware or auxiliary equipment, which Yokogawa did
not supply.
Failureduetoimproperorinsu󰀩cientmaintenancebyuser.
Failureduetomisoperation,misuseormodicationwhichYokogawadoesnotauthorize.
Failureduetopowersupply(voltage,frequency)beingoutsidespecicationsorabnormal.
Failure caused by any usage out of scope of recommended usage
Anydamagefromre,earthquake,astormandood,lightning,disturbance,riot,warfare,
radiation and other natural changes.
 Yokogawadoesnotwarrantconformancewiththespecicapplicationatthe
usersite.Yokogawawillnotbeardirect/indirectresponsibilityfordamagedue
toaspecicapplication.
 Yokogawawillnotbearresponsibilitywhentheusercongurestheproduct
intosystemsorresellstheproduct.
 Maintenanceserviceandsupplyingrepairpartswillbecoveredforveyears
aftertheproductionends.Forrepairthisproduct,pleasecontactthenearest
saleso󰀩cedescribedinthisinstructionmanual.

i
<CONTENTS>
IM 11G02Q02-51EN 2nd Edition : Sep. 04, 2020-00
Model IR202
Infrared Gas Analyzer
Communication Functions (MODBUS)
CONTENTS
IM 11G02Q02-51EN 2nd Edition
uPREFACE........................................................................................................i
uSafety Precautions.......................................................................................ii
uAfter-Sales Warranty...................................................................................iv
1. GENERAL.................................................................................................. 1-1
2. CONNECTION........................................................................................... 2-1
3. MODBUSPROTOCOL.............................................................................. 3-1
3.1 Compositionofmessage................................................................................. 3-1
3.2 Responseofslavestation................................................................................ 3-2
3.3 Functioncode.................................................................................................... 3-3
3.4 Calculationoferrorcheckcode(CRC-16)..................................................... 3-4
3.5 Transmissioncontrolprocedure..................................................................... 3-6
4. DETAILSOFMESSAGE........................................................................... 4-1
4.1 Read-outworddata(Functioncode:03H)..................................................... 4-1
4.2 Read-outworddata(Read-outonly)(Functioncode:04H).......................... 4-2
4.3 Write-inworddata(1word)(Functioncode:06H)....................................................... 4-4
4.4 Write-incontinuousworddata
(Functioncode:10H)........................................................................................ 4-5
5. ADDRESSMAPANDDATAFORMAT..................................................... 5-1
5.1 Dataformat........................................................................................................ 5-1
5.1.1 Handling of decimal point position and measurement unit................ 5-1
5.1.2 Handling at measurement data over-range....................................... 5-2
5.2 Addressmap..................................................................................................... 5-3
5.3 Supplementtoaddressmap.......................................................................... 5-16
6. TROUBLESHOOTING............................................................................. 6-1
Revision Information...............................................................................................i

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<1. GENERAL> 1-1
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
1. GENERAL
This product provides a communication function through RS-485 interface, which allows data
transmit to or receive from the host computer and other devices.
The communication system is comprised of a master station and slave stations. Up to 31 of slave
station (present instrument) can be connected per master station (host computer, programmable
controller, graphic display panel, etc.) through RS-485 interface.
Because the master station can communicate with only one slave station at a time, the
destinationcanbeidentiedbythe“StationNo”setforeachslavestation.
In order that the master station and the slave station can communicate, the format of the
transmit/receive data must coincide. The format of the communication data is determined by the
MODBUS protocol
[RS-232 <=> RS-485 converter] (recommended )
Type: KS-485 (non-isolated type)/SYSTEM SACOM Corp.
Type: SI-30FA (isolated type)/SEKISUI ELECTRONICS Co., Ltd.
[USB <=> RS-485 converter] (recommended article)
Type: USB-485I / SYSTEM SACOM Corp.
RS-485 USB RS-485
RS-232C RS-485
RS-485
Programmable controller
Converter
IR202 IR202
RS-232C or USB
Figure1.1 Congurationbetweenmasterandslavedevices

<1. GENERAL> 1-2
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
l RS-485Interface
Electricalspecication: BasedonEIARS-485
Transmission system : 2-wire, semi-duplicate
Synchronizing system : Start-stop synchronous system
Connection format : 1*N
Maximum connectable units : 31 units
Transmission distance : 500 m max.(total extension distance)
Transmission speed : 38400 bps
Data format
Data length ; 8 bits
Stop bit ; 1 bit
Parity ; None
 Xowcontrol; None
Transmission code : HEX value (MODBUS RTU mode)
Error detection : CRC-16
Isolation : Isolation from internal circuit
Functional isolation between signal line and ground

<2.CONNECTION> 2-1
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
2. CONNECTION
WARNING
Do not turn on the power supply until all wiring have been completed, otherwise electric shock or
malfunctions may occur.
n RS-485Interface
The terminal allocation of RS-485 (at the rear panel)
5 4 3 2
9 8 7 6
1
1: Signal ground
2: RTxD+
3: RTxD-
4 to 9: NC
9-pin D-Sub (female)
RS-485 interface requires
• Use a shielded twist pair cable. (Recommended cable: KPEV-SB (made by The Furukawa
Electric Co., Ltd.))
• The maximum cable length should be 500m. One master and up to thirty-one micro
controllers (slaves) can be connected per circuit.
• Terminatebothendsofthecircuitwithaterminatingresistanceof100Ω(1/2Wormore).
• Ground the shielded cable once towards the master side

<2.CONNECTION> 2-2
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
RTxD+
+
+
-
SG
-
+
-
RTxD-
Master Slave
Terminating resistance
100Ω(1/2W)
Terminating resistance
100Ω(1/2W)
Shielded twist pair cable
RS-485 interface
or
RS-232C
(USB)
IR202
IR202
IR202
RS-485 side of
RS-485 converter
• SGdoesnothavetobeconnected,butitcanbeusedasane󰀨ectivecountermeasure
against communication errors due to noise.
• When using the micro controller in an area where the imposed noise level is expected to
exceed500V,werecommendusinganoiselteronthemastersideasseeninthegure
below.
WerecommendRSHN-2003(madebyTDKCorporation)asanoiselter.
RS-485
IR202
Noise filter
Programmable controller
or
Personal computer
+ RS-232C to RS-485 converter
• If there are problems with EMC during communication, the noise level can be reduced by
using a communication cable with a ferrite core.
Ferrite core (recommended): ZCAT series (made by TDK Corporation)
MSFC series (made by Morimiya Electric Co., Ltd.)

<2.CONNECTION> 2-3
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
nSETTING OF COMMUNICATION CONDITION
The following list shows the required setting to establish communication between a master
device and IR202.
• Set up correctly so that the communication conditions of all IR202s must be same as
master’s.
• EachIR202inalinemustbeassigneddi󰀨erentStationNo.fromeachother.StationNo.is
never shared with any other IR202 in the same line.
The table below shows the items to setup. Set them by operating the front panel keys.
Item Value at delivery Setting range Remarks
Transmission speed 38400bps Fixed (can not be changed) Set up correctly so that the
communication conditions of
all IR202s must be same as
master’s.
Data length 8 bits Fixed (can not be changed)
Stop bit 1 bit Fixed (can not be changed)
Parity setting None Fixed (can not be changed)
Station No. 10 to 31
(0 : communication function stop)
Each IR202 in a line must
beassigneddi󰀨erentStation
No. from each other. Station
No. is never shared with any
other IR202 in the same line.
Set the station No. in the maintenance mode of IR202. (See the instruction manual.)

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<3. MODBUS PROTOCOL> 3-1
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
3. MODBUSPROTOCOL
According to MODBUS protocol, devices communicate using a master-slave technique, in whch
only one device (the master) can initiate transactions. The other devices ( the slaves) respond by
supplying the requested data to the master, or by taking the action requested.
<Message transaction between Master and Slave>
(1) The master station sends out a command message to a slave station.
(2) The slave station tries to identify the station No. in the received message with its own station
No..
(3) Iftheslavestationndsthosenumbersmatched,itexecutestheactionrequestedinthe
received command and sends back a response message.
If those numbers are mismatched, the slave station leaves the command message and
waits for next command message
 When the station No. in the received command message matches with the own slave station
Command message
Response message
Slave to master
Master to slave Data on
the line
 When the station No. in the received command message mismatches with the own slave station No.
Command message
(Not respond)
Slave to master
Master to slave Data on
the line
The master station can individually communicate with any one of slave stations connected on the
same line upon setting the station No. in the command message.
3.1 Compositionofmessage
Commandmessageandresponsemessageconsistof4elds;StationNo.,Functioncode,Data
and Error check code, which are sent in the following order:
Station No. (1 byte)
Function code (1 byte)
Data (2 to 133 bytes)
Error check code (CRC-16)(2 bytes)
 Figure.3-1 Compositionofmessage
(1)StationNo.
Station No. is slave address or a number specifying a slave station. Station No. are set in the
maintenance mode display. Only a slave with the same number as this Station No. set in the
maintenance mode can respond to the message and take action requested in the received
message.
(2) Function code
This is a code to designate a function to request slaves to execute. For details, refer to section
“3.3 Function code”.

<3. MODBUS PROTOCOL> 3-2
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
(3) Data
Dataeldisrequiredtoexecutefunctioncodes.Thedataconstructiondependsonfunctioncode.
For details, refer to “4. DETAILS OF MESSAGE”
A register number is assigned to each data in IR202. For reading / writing the data by
communication, designate the register number.
Note that the register number transmitted on message is expressed as its relative address.
The relative address is calculated by the following expression.
Relative address = (The lower 4 digits of( the registered number or coil)) - 1
For example, when the registered number designated by a function code is 40003,
Relative address = (lower 4 digits of 40003) – 1 = 0002
is used on the message.
(4)Errorcheckcode
This is the code to detect message errors (change in bit) in the signal transmission.
On the MODUBUS protocol (RTU mode), CRC-16 (Cyclic Redundancy Check) is applied.
For CRC calculation method, refer to “”
3.2 Responseofslavestation
(1)Responsetonormalcommand
To a relevant message, the slave station creates and sends back a response message which
corresponds to the command message. The composition of message in this case is the same as
in section 3.2.
Contentsofthedataelddependonthefunctioncode.Fordetails,referto“4. DETAILS OF
MESSAGE”
(2)Responsetoabnormalcommand
If a command message contains an abnormality (for example, non-actual function code is
designated) other than transmission error, the slave station does not execute that command but
creates and sends back a response message at error detection.
ThecompositionofresponsemessageatanerrordetectionisasshowninFigure3-2.Tollin
theeldoffunctioncode,sumthevaluesofFunctioncodeinthereceivedcommandmessage
and 80H,thenputthevalueintotheeldoffunctioncode.
Station No.
Function code +80H
Error Code
Error check (CRC-16)
 Figure3-2 Responsemessageaterrordetection
Table3-1Errorcode
Error code Contents Description
01H Illegal function Non-actual function code is designated. Check for the function code.
02H Illegal function A relative address of a register number to which the designated function code
can not be used.
03H Illegal function Because the designation of number is too much, the area where register
numbers do not exist is designated.

<3. MODBUS PROTOCOL> 3-3
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
(3)Noresponse
Under any of the following conditions, the slave station takes no action to the command message
and sends back no response.
• Astationnumbertransmittedinthecommandmessagedi󰀨ersfromtheStationNo.(station
number)speciedtotheslavestation.
• An error check code is not matched, or a transmission error (parity error, etc.) is detected.
• The time interval between the composition data of the message becomes longer than the
time corresponding to 24 bits. (Refer to “”)
3.3 Functioncode
According to MODBUS protocol, register numbers are assigned by function codes.
Eachfunctioncodeactsonspecicregisternumber.
This correspondence is shown in Table 3-2, and the message length by function is shown in
Table 3-3.
Table3-2 Correspondencebetweenfunctioncodesandobjectiveaddress
Function code ←→ RegisterNo.
No. Function Object No. Description
03HRead-out (continuously) Holding register 4xxxx Read-out / write-in word data
04HRead-out (continuously) Input register 3xxxx Read-out word data
06HWrite-in Holding register 4xxxx Read-pit / wrote in word data
10HWrite-in (continuously) Holding register 4xxxx Read-out / write-in word data
Table3-3Functioncodeandmessagelength     (Unit:byte)
Function
Code
Contents Numberof
designatabledata
Command message Responsemessage
Minimum Maximum
Minimum Maximum
03HRead-out of word data 64 words 8 8 7 133
04HRead-out of word data
(read-out only)
64 words 8 8 7 133
06HWrite-in of word data 1 word 8 8 8 8
10HWrite-in of continuous
word data
64 words 11 137 8 8

<3. MODBUS PROTOCOL> 3-4
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
3.4 Calculationoferrorcheckcode(CRC-16)
CRC-16 is the 2-byte (16-bits) error check code. From the top of the message (station No.) to the
endofthedataeldarecalculated.
The slave station calculates the CRC of the received message, and does not respond if the
calculatedCRCisdi󰀨erentfromthecontentsofthereceivedCRCcode
The following shows the calculation procedure for CRC-16.
(1) Store FFFFHinto 16 bit register (CRC register).
(2) Subject the 1st byte (8 bits) of transmit message and CRC register contents to an exclusive
logical summation (XOR), and store the result into the CRC register.
(3) Shift the CRC register contents 1 bit to the right. Store 0 at MSB.
(4) If LSB before shifting is 0, do nothing. If LSB before shifting is 1, subject it and A001H to
XOR, and store the result into the CRC register.
(5) Repeat the steps (c) and (d) 8 times (shift by 8 bits).
(6) Execute steps (b) to (e) for the next byte of the transmit message. Likewise, successively
repeat the steps to each byte of the transmit message.
(7) The CRC code that is retained is the value of CRC register that stands when the processing
has ended for latest byte (latest data except error code) of the transmit message.
(8) As error check code of the transmit message, store this CRC value in the order of lower 8
bits and upper 8 bits
Transmit message (ex.)
01H
06H
00H
05H
03H
E8H
99H
75H
Transmit message (ex.)
Successively calculate data
included hereto obtain CRC.
In this case, CRC = 75 99H.
Attach the error check code to
message upon interchanging
the upper and lower orders.

<3. MODBUS PROTOCOL> 3-5
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
Explanation of variables
CR: CRC error check data (2 bytes)
I: Digits of calculation characters
in command message
J: Check on the number of times
of CR calculation
Start
Set FFFFH(hexadecimal number) in CR.
Set 1 in I.
Exclusive logical sum (XOR) is executed
with CR and one character (1 byte) of #I of
the message, and its results is set in CR.
Set 1 in J.
Bit at right end
of CR is 1?
Shift CR to right by 1 bit, and A001Hand
exclusive logical sum (XOR) are executed
and its result is set in CR.
Shift CR to right
by 1 bit.
Add 1 to J.
Calculation (8 times) is
finished?
J>8
Add 1 to I.
Calculation of all characters
is completed?
I>All characters
End
(Calculation is executed in the order of
command message station No., function
code and data.)
CR calculation result shall be added to
the last command message in the order
of LOW byte and HIGH byte.
NO
NO
NO
YES
YES
YES
Figure3-3 CRC-16calculationowchart

<3. MODBUS PROTOCOL> 3-6
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
3.5 Transmissioncontrolprocedure
(1)Transmissionprocedureofmasterstation
The master station must proceed to a communication upon conforming to the following items.
• Before sending a command message, provide 48 bits time or more vacant status. (a)
• For sending, the interval between bytes of a command message is below 24 bits time. (b)
• Within 24 bits time after sending a command message, the receiving status is posted. (c)
• Provide 48 bits time or more vacant status between the end of response message reception
and beginning of next command message sending [same as in (a)].
• Forensuringthesafety,makeaconrmationoftheresponsemessageandmakean
arrangement so as to provide 3 times or more retries in case of no response, error
occurrence, etc.
NOTE
Theabovedenitionisformostunfavorablevalue.Forensuringthesafety,it’srecommended
the program of the master to work with safety factors of 2 to 3. Concretely, it is advised to
arrange the program for 38400 bps with 5 ms or more for vacant status (a), and within 1 ms for
byte interval (b) and changeover from sending to receiving (c).
(2) Description
(1) Detectionofthemessageframe
The status on the line of the communication system is one of the 2 below.
(a) Vacant status (no data on line)
(b) Communication status (data is existing)
Instruments connected on the line are initially at a receiving status and monitoring the line.
When 24 bits time or more vacant status has appeared on the line, the end of preceding frame is
assumed and, within following 24 bits time, a receiving status is posted. When data appears on
the line, instruments receive it while 24 bits time or more vacant status is detected again, and the
endofthatframeisassumed.I.e.,datawhichappearedonthelinefromtherst24bitstimeor
more vacant status to the next 24 bits time or more vacant status is fetched as one frame.
Therefore,oneframe(commandmessage)mustbesentuponconrmingthefollowing.
• 48 bits time or more vacant status precedes before the command message sending.
• Interval between bytes of 1 command message is smaller than 24 bits time.
(2) ResponseofIR202
After a frame detection (24 bits time or more vacant status), IR202 carries out processing
with that frame as a command message. If the command message is destined to the
own station, a response message is returned. Its processing time is 1 to 30 ms (depends
on contents of command message). After sending a command message, therefore, the
master station must observe the following.
• Receiving status is posted within 24 bits time after sending a command message

<4. DETAILS OF MESSAGE> 4-1
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
4. DETAILSOFMESSAGE
4.1 Read-outworddata(Functioncode:03H)
Function
code
Max.wordnumberread-out
in one message
Relative data
address
RegisterNo. Contents
03H64 word 0000-009DH40001-40158 User setting
(1) Messagecomposition
Command message composition (byte) Response message composition (byte)
Read-out word number x 2
Station No Station No
Function code Function code
Read-out byte number
Upper byte of contents of the first word data
Lower byte of contents of the first word data
Upper byte of contents of the next word data
Lower byte of contents of the next word data
Upper byte of contents of the last word data
Lower byte of contents of the last word data
* Arrangement of read-out word data
MSB LSB
CRC data
CRC data
Read-out word
number
Contents of the
last word data
Contents of the
next word data
Contents of the
first word data
Upper
Lower
Upper
Lower
Upper
Lower
Lower
Upper
Upper
Lower
Upper
Lower
Lower
Upper
Read-out start No.
(relative address)
1 to 60
(2) Function
Word data of continuous word numbers from the read-out start No. can be read. Read-out word
data are transmitted from the slave station in the order of upper and lower bytes.