Recently, the program was wiped from the PLC controlling our frozen storage compressor/evaporator/condenser system. We didnt have a copy because we relied on a third-party for service. frankly, the manager wasn't even aware that there was a PLC in the control cabinet.
Third-party shut off the power in the morning, changed oil and did other PMs throughout the day, then swapped a new 1747-OW16 for an old one with a bad relay. Upon powering back up, program was erased. I'm guessing the battery was bad and it was shut down long enough to lose the program. The service provider says they were sold the wrong version of the OW16, it faulted, then it wiped the program.
My question is... What it the most likely cause of program loss - my scenario or theirs?
Third-party shut off the power in the morning, changed oil and did other PMs throughout the day, then swapped a new 1747-OW16 for an old one with a bad relay. Upon powering back up, program was erased. I'm guessing the battery was bad and it was shut down long enough to lose the program. The service provider says they were sold the wrong version of the OW16, it faulted, then it wiped the program.
My question is... What it the most likely cause of program loss - my scenario or theirs?