Please, what are the major causes of PLC failure? I need to know general procedure on how to troubleshoot on a plc. my PLC brand is omron. the last problem I had with it was there was a power outage but after the power was restored my PLC doesn't accept any command from the display unit. Although, I later discovered that the safety network controller does not supply the 24v dc to the slave panel plc. my plc model number is CJ1M CPU12-ETN. thanks.

Regard,
Femi

 

Some PLCs retain their programs off battery power. If the unit has been in service for a few years the battery may have died and when you lost power the program was lost. If this is the case not only will you need a new battery but I hope you have the program backed up somewhere as no trace of it is left in the PLC.