1769-L32E Rev 20.12

1769-L32E REV20.12

I have had a customer PLC loose the date twice now on the same PLC. I ask if there have been any power outages and they say no.

Every time I go in to check the date/time it shows ??
If I look at wallclock year it shows 1969.
it has happened 4 months apart. month and day went to 4/22.

The PLC does not stop in operation but some numbers I am recording using hour/day/month get screwed up.

Anyone else see this behavior?

Check for SSV instructions and see if any are addressing the WALLCLOCK object. That way you can identify if anything in the logic is changing the time.

You might look at programming something to capture power cycles. Just in case they aren't catching power blips. You could do something simple like a XIC bit using S:FS and triggering a counter.

OG

Upgrade the firmware. There have been some problems where the RTC got stuffed up in some versions.