Hanging or invalid CEX IRQ: All CEM's on the upper CEX bus segment are disabled
have a PM891 which has a CEX bus error, the error is: Error on backup unit, Backup CPU stopped, Hanging or invalid CEX IRQ: All CEM's on the upper Cex bus segment are disabled, Hanging or invalid CEX IRQ: A PM has been shut down, Redundant mode enabled.
There is also several "connection down" displayed in the CI867 oveview on several gateway's. However most of the gateway channels are working
I sincerely recommend contacting your regional ABB support center.
The controller log(s) often contain crucial evidence about what brought the unit down. CBM->Maintenance->Remote System->Controller log.
Please have the logs extracted & securely stored in case support request a copy of them. Due to onboard storage restrictions, logs are circular and will eventually overwrite themselves.
please contact the regional ABB support centre with controller log files in the following path controller node right click remote system-controller log.
This might may happen because of the somebody disturbed the CEX bus or CEX bus is not properly fastened with the controllers.
please share the log files to understand more in details