YOKOGAWA IR202, User Manual

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<4. DETAILS OF MESSAGE>
4-3
IM 11G02Q02-01EN 2nd Edition : Sep. 04, 2020-00
(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)
(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
(3) Message transmission (example)
The following shows an example of reading out from No. 1 station the Ch5 measurement
concentration, decimal point position and measurement unit.
Relative address of Ch5 measurement concentration: 000C
H
Data number: 03
H
Command message Response message
Station No. 01H Station No. 01H
Function code 03H Function code 03H
Read-out start No.
(relative address)
Upper 00H Read-out byte number 06H
Lower 0CH
Contents of the first
word data
Upper 04H
Read-out word
number
Upper 00H Lower B0H
Lower 03H
Next word data
contents
Upper 00H
CRC data
Lower 70H Lower 02H
Upper 08H
Latest word data
contents
Upper 00H
Lower 00H
CRC data
Lower 81H
Upper 0DH
• Meaning of read-out data
First word data contents 04 B0
H
= 1200
Next word data contents 00 02
H
= 2 (decimal point position)
Latest word data contents 00 00
H
= 0 (vol %)
In the above case, measurement concentration = 12.00 vol%