Server redundant computer configurations that use the CCM2 Communications option must be configured as in the following diagram:
The primary and secondary servers must have independent cable paths to the PLC. The PLC must have two serial ports available for CCM2 communications. Both of the PLC's serial ports must be configured with the same CPU ID.
The recommended configuration is to use the CMM module in CCM2 mode. Both ports on the CMM module can be configured for CCM2 communications.
Supported communication interfaces.