Sercouse module sometimes going fault mode.

Hi guys,
Our Plc sercouse interface module sometimes going fault mode.it's OK indication led solid red.if this fault occurred the all servo drive going fault mode.it is happening since one year
We don't have idea why this fault occurred. Every time we down power cycling and restored
Restored normal operation.kindly note that there is two CPU and one CPU battery is now on fault mode.we are waiting for new battery replacement.
Kindly any idea would be great appreciate.

Jamal

Going online while the sercos is faulted and looking at the fault codes maybe a good start.

Thanks for your suggest. OK we will check online when there is sercose fault and we will post the details fault code.