What is the difference between the MVI56-MCM and the MVI56-MCMR?

The MVI56-MCM is our general purpose Modbus serial (RTU and ASCII are supported) master/slave solution for ControlLogix, and is the preferred choice when used in the local chassis with the controller, or in a remote chassis via Ethernet.

The MVI56-MCMR communicates across the backplane to the remote chassis using smaller I/O blocks and is intended for ControlNet applications. This reduced I/O size makes the MVI56-MCMR module easier to schedule in RSNetworx for ControlNet and will have less impact on the other ControlNet I/O.

MVI56-MCM - I/O mapping (250 input words and 248 output words)
MVI56-MCMR - I/O mapping (42 input words and 42 output words)

MVI56-MCM - configuration in RSLogix 5000 controller tags
MVI56-MCMR - configuration created offline in Prosoft Configuration Builder app and downloaded via serial cable