Rockwell Automation Publication 2080-UM002L-EN-E - November 2021 27
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
When the new node address is configured and applied, the port is not
restarted.
You can verify that the node address has changed after performing RMCC by
looking at the Communication Diagnostics tab for the controller.
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
IMPORTANT
You must ensure that the new node address being configured is unique as it
will not be checked against existing node addresses of other devices.
To Next Page
Loading...
Need help?
General
