Omron CJ2M-CPU Series Connection Guide

9
．
Program
43
●Send/Receive messages
[Frames of send/receive messages]
[S:Relation between the first command word (CMND instruction operand) and send
messages]
[D:Relation between receive messages and the first response word (CMND instruction
operand)]
Additional Information
Silent interval: Waiting time to recognize the first frame using Modbus-RTU communication.
During the reception standby, the first received data is deemed as the first byte of frame after
the waiting time of 3.5 characters with actual baud rate.
Additional Information
Error check: 16-bit data is expressed with two 8-bit data for Modbus-RTU communication.
Error check result is calculated by the calculation formula called CRC (Cyclical Redundancy
Check).
Send message
Silent
interval
Address
*
*
PLC
Receive message
Destination
Device
**
Function
code
**
**
**
Error check
Data
**
**
Silent
interval
Silent
interval
Address
**
**
**
**
**
Data
**
**
Silent
interval
Function
code
Error check
SCU
→
Destination
Device
Send message
CPU
→
SCU
S: First command word
Bit
Silent
interval
Address
**
**
Function
code
**
**
**
Error check
Data
**
**
Silent
interval
28
04
+0CH
+1CH
**
**
**
**
**
Command code
Destination Device
→
SCU
Receive message
SCU
→
CPU
D1: First response word
：
Bit
Silent
interval
Address
**
**
Function
code
**
**
**
Error check
Data
**
**
Silent
interval
Command code
End code
28
04
+0CH
+1CH
+2CH
**
**
**
**
**
**
**

Omron CJ2M-CPU Series Specifications

General

Brand	Omron
Model	CJ2M-CPU Series
Category	Controller
Language	English