1769-OB16 - all outputs are off with CompactLogix running

[cstca]

I have a system with L35E and a couple of DI/DO AI/AO. The system was installed and running for 1 year now. At some point last week, none of the outputs will turn on. PLC still running, all IO cards were okay (IO tree shows all green, no yellow triangle). With PLC in remote run mode, outputs were turning ON/OFF in RSLogix5k when online with the processor (just in software, no light on the LED and no physical output). Checked 24 VDC on the card - all good. The only way to fix this issue was to cycle power to the PLC. After that, without changing anything (software or electrical), DO start working. Could be an issue with processor (firmware 18.12)? The customer mentioned a spike in voltage last week (to the entire plant). Could this spike create the issue in the cards? We have surge suppresor, UPS and power supply 120/24VDC. There were 2 DO cards, both showing same simptom. DI and AI were still working when they had the issue with DO (I dont know anout AO). Firmware on the DO card was 3.1 (in software setup as 2.1). I've tried knowledgebase but it seems to be down this morning.
Thx.

 

[cornbread]

I recall having some thing like this... I don't remember the exact details, but it had to do with minor faults in the PLC.... after so many we had to restart the PLC. There was something wrong with the comm setup... I'll have to check and get back.