Hardware problems Micrologix 1500

I have recently started to work with an OEM in Thailand making packaging machinery. I was just informed that they have sold 12 machines to a "global major food manufacturer" using Micrologix 1500 as per customer request. 5 of the units get a total memory blackout after power down over night. The rest is fine. AB locally have been there without result, my new emplyer can't solve it and AB themselves ignore it.

Is there are known hardware issues related to inverter interferecne or such?

Anyone know about this problem?

Of course we have tried to move the cpu's, filter basically everything, all without result.

Greatful for help or more information!!!

Nick

Do these PLC have the same programming fault recovery systems?
Do these PLC have EEprom?
Have you implemented a recovery routine in your program?
Is the "load from EEPROM" function turned on, and EEPROM present and "burned" with current program?
Did you change the battery for the backup?
Is the battery connector inserted correctly?
If some work and not the others, look for a difference from them.
Exchange PLC programs with others and notice a difference, exchange EEPROMS if you use them.
Swap out a faulty PLC with a working unit. oooops you did! I think!
If you think it is a power problem, connect a "known" good PLC on the same power supply as the "known" bad one at the same time.
These test should give you a better idea as to what the cause of failure is.
Last of all if the serial numbers are widely different, ask about a product recall and ask the supplier to provide a NEW test unit.
With all of the money you have already spent they should be happy (if not obligated) to supply a test PLC!

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