18 Rockwell Automation Publication 2080-UM002K-EN-E - March 2019
Chapter 2 About Your Controller
Using Modbus RTU Communication
To use RMCC with the Modbus RTU communication protocol, the serial port
must be set to the Modbus slave role. A CIP Generic message is sent from within
a program with the following parameters.
RMCC Modbus Example – Set the Parameters
RMCC Modbus Example – Set the New Node Address
The first byte indicates the new node address for the controller. For this example,
the new node address is “3”. The second byte must always be “1”, this indicates
that the Modbus role is configured as Slave.
RMCC Modbus Example – Set the Message Length
CIP Generic Message Parameters for RMCC using Modbus RTU
Parameter Value
Service 16
Class 70
Instance 2 – Embedded serial port
5, 6, 7, 8, or 9 – Plug-in modules
Attribute 100
ReqData New node address, 1
ReqLen 2