RX3i Dual Bus Genius Redundant Controller

I submitted an inquiry via Technical Support Service Request, the Senior Support Professional who handled my question suggested I use this form to continue my inquiry.

A customer is running redundant RX3is with a dual Genius Bus. There are 16 IC200GBI001s on the Genius Buses. The customer experienced a loss of communications to SBA 12. The fault table shows a loss of the Primary PLC, a failure of the Memory Exchange module (IC695RMX128) and the return of the Primary PLC as backup to the Secondary. When the Secondary took over communications was lost with SBA 12. SBA 12 appeared to be communicating with PLC. Switching the active PLC to the Primary returned communications to SBA 12 and subsequent switches between the Primary and Secondary as the active PLC did not result in a loss of communication.

There are password protected program blocks. Could the events I have described have found a fault in these program blocks?

This occurred at the same time as a loss of power. The loss of power should not have affected the PLCs or GBIs on the Genius Bus as entire system is on a 6 hour UPS, emergency generator, and fixed battery back up. Still it seems odd to have happened at the same time.

Thanks for your help.

Jim