PLC turning itself OFF aand back ON

[rickshea1]

We have about 7 Terminator Do Mores in the field. All work well but one (1). The CPU will turn itself "OFF" and than back "ON" maybe twice in 8 hours for no reason. We've check all the wiring and all the wiring is good. We use the Terminator 24 vdc power unit only to supply the CPU. We use a separate P.S. for the rest of the I/O. We've replaced the CPU but have the same results. Two of my thoughts are 1. replace the power supply. 2. This company has two (2) or three (3) rather large transformers with-in 4 feet of our machine could this cause a problem?

Has anybody else had a problem like this?

[BobO]

What is the value in DST385 ($WatchdogReboots)?

[rickshea1]

I have no idea. I've never looked at that register. I have a man in the field updating is computer software so he can attach. I'll have him look. Whats the importance or what should I be looking for?

[BobO]

When a DM1x CPU reboots itself due to a watchdog timeout, it sets $WatchdogReboot (ST13) and increments $WatchdogReboots (DST385). If it is crashing and restarting, it is likely due to noise. If the watchdog counter is not incrementing, it is likely a failure in the power supply (which could be noise, unstable power, or bad power supply).

[rickshea1]

That's great information. I'll have to get back to you. It could take some time before my man gets back to me.

Thank You