PLC crashes after syntax check

[kmuldrew]

DL 205 with DS260 and a whole lot of I/O cards running a reasonably large plant. I rerouted an input wire to a different card, changed the input location using DirectSoft 32 v.4, saved to disk (but not to PLC) and then ran a syntax check (I didn't mean to, but that is what I did). The PLC crashed and brought the plant down. After turning the PLC from "term" to "stop", then to "run" and back to "term", everything came back on line (whew!).

Should this have happened? Can a syntax check when the PLC and the saved program are out of sync really bring down the whole operation? I wonder if a careless click of the syntax check function should put so much automation in jeopardy.

[franji1]

Whoa!?!  Syntax Check is done by the PLC firmware in the PLC.  Not sure what happened there.  You may want to contact AutomationDirect techsupport.

[b_carlton]

I wonder if a Syntax check while running a very large program could trigger a Watchdog timeout?

[franji1]

I don't know, but that would be a good question to ask ADC Tech Support.

[Greg]

My understanding of this after talking to AD about it, is the CPU does the syntax check (not DirectSOFT), but the issue is it cannot do that in RUN mode. The CPU should be put in the STOP mode before doing this.