PLC Mysteriously going to remote program

[careed_25]

We had a control logix processor mysteriously get set to remote program mode this morning. When someone got in front of it the key was in the remote position. My question is, has anyone ever seen the processor put itself in program mode without the key being turned or without someone telling it to go to program from logix5000 software? We have four 1336 impact drives talking over controlnet to the processor and the scanport on the first drive fualted this morning. I am wondering if this could have had an effect on the state of the processore and somehow put it in program mode? This could possibly be that once the drive wouldn't clear someone took it upon themself to switch the key to program and isn't owning up to it. Like i said earlier in the post I want to know if the processor could glitch and put itself in remote program. Normal state is remote run.

 

[Operaghost]

You can write logic to have the PLC switch itself to Program mode. But the PLC switching itself, without that logic.....never seen it.

If there had been a fault then it would be in Fault mode. Unless as you suggest someone toggled the key and isn't owning up to it.

OG.

 

[Roy Matson]

I have a PLC in Class 1 Div 2 purged cabinet. I leave the key in remote program otherwise I cannot do changes because I can't open the cabinet.
If someone is smart enough to use RSLogix 5000 they can be trusted not to screw the configuration up.

 

[LJBMatt]

The only thing I can think of would be a major fault is set on the PLC but somehow gets cleared etc. On a major fault clear the PLC will go to Remote Program mode if the Keyswitch is in REM.

 

[Ken Roach]

Check the configuration of the I/O connection to the IMPACT drive to see if it's set to cause a Major Fault if the connection fails in RUN mode. That might be one of the steps in your chain of events that led to the drive being faulted and the controller being in Remote Program.

 

[Ken Roach]

It's the English majors in my life that make me careful about language regarding absolutes. That, and reading Douglas Adams as a teenager.

With a programmable electronic system, nothing is "impossible".

A ControlLogix controller switching into Remote Program mode without being commanded to do so by an external device is in the category of "very improbable".

I have never witnessed it or heard about it occurring.

But I've definitely witnessed faults occurring and being reset by power cycles, and regularly detect unauthorized users taking unobserved and unrecorded actions.