PLC dropping out of run mode

[mhw]

A customer of mine has a D2-260 CPU that sporadically drops out of run mode. He moves the mode switch to stop and then run and it will restart. I was onsite today and there are numerous "E250 I/O bus failure" shown on the system errors tab of the PLC messages. Is there a way to determine exactly where the problem is? It has a 9 slot base that is full and a 4 slot expansion base.
Thanks,
Mike

[franji1]

A customer of mine has a D2-260 CPU that sporadically drops out of run mode. He moves the mode switch to stop and then run and it will restart. I was onsite today and there are numerous "E250 I/O bus failure" shown on the system errors tab of the PLC messages. Is there a way to determine exactly where the problem is? It has a 9 slot base that is full and a 4 slot expansion base.
Thanks,
Mike

I recommend also posting this on ADC's Community forum.  260 is not a Host product (it's made by Koyo).  You will get much more eyes/better answers posting over there.

[ADC Product Engineer]

Pretty much anytime a PLC drops out of run mode it is because of power or noise; unsuppressed coils, VFD wiring that is too close to other wiring, welders, powder coating machines, etc, etc.  Something is either mucking with the PLC power or hammering the communications lines.

Since there is an E250 error the first thing I would suspect is poor power to the expansion rack.  If that isn't it, then I would look for noise sources.  If neither of those bear fruit, then I would replace the bases as a last resort.

[Controls Guy]

How old are the bases?  Back in the days before fire, I had a couple 305 bases (I think one was old enough to be a TI brand) where the power supply caps aged out and the PLCs started doing weird inexplicable stuff.   DL06 once, too, but in that case it only affected some analog readings.

[mhw]

Thanks for the responses.
Franji1,
Thanks for the advice but I'm at the point where I'd rather have a tooth pulled than go there. It is not the friendly, helpful, and knowledgeable site that it used to be and that Host still maintains.

ADC product Engineer,
Do you think that a filter on the incoming power like the Eaton ADPV##### would help?

Controls Guy,
They were installed in 2008.

[Controls Guy]

Then I think check for noise like ADC PE says and just replace the bases. After 14 years, if they're not the cause of this problem, it's time to replace them for PM.

X100 on the new ADC forum.   I used to go several times a week.  Since they changed, I've been maybe 3 times.