Override Key on AB PLC's

Anyway, I can get the processors into remote run, once they are in remote run can I add something that overrides the key.? I know in controllogix I can monitor with a GSV but can I add logic that even if the key is turned it will not allow the processor into that mode?
 
Its a long story, however there is an electrician that keeps turning it to run and throwing away the key.

You could take the module apart, removing the switch and hard-wiring it into REMote mode, not advised...

You could just put a sticker over the keyhole...

You could fabricate a wire cage that surrounds the chassis, with padlocked access...

You could fabricate a bracket that you can padlock the key to, held in the REMote position...

You could wire up a "sound bomb" that only sounds in the RUN position...

You could stop your processes from running if the keyswitch is not in the REMote position (a bit severe, but it'll get noticed by the management)...

But quite frankly the simplest thing to do is to educate said electrician why you have to have the key in whatever position you want. If he still keeps turning it, report him to his superiors...
 
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There really is no way to change the controller state unless the key switch is in the REMOTE RUN position (this allows for 'remote control' via user software)

Put the key into REMOTE RUN and then remove it and place it into a 'need to' accessible storage place; it is standard procedure in plenty of high-security industrial/utilities operations.
 
there is an electrician that keeps turning it to run and throwing away the key

sounds like a job for management to me ...

my Uncle Harry used to say: "You don't have to catch ALL of the foxes. Just catch ONE and nail his hide to the henhouse door. The rest of the foxes will get the message."

the big question is: if he's doing this sort of thing that you KNOW about - what is he also doing that you haven't caught him doing yet? ...
 
If you can override something hardwired, is it really hardwired?

+1 to keeping the key somewhere safe. The controls engineers (and select *trained* members of maintenance) should be the only people with access to that sort of stuff anyway.
 
I feel davidhinch's pain...

I once worked on a large brewery project where I got short straw and had night-shift commissioning/trials to do. I needed to make some changes on a remote PLC, but someone had put it into RUN position.

I had to walk the 2 miles there, turn the key, then 2 miles back, to do the changes.

Needless to say most of those 4 miles were outdoors...

It was 3:30 a.m., about -8 deg.C, windchill probably made it feel more like -15, and it had been snowing.

I eventually discovered who had put it into RUN, and I told him next time he did it I'd make him take a walk.....
 
All of us who have been involved in factory automation for any length of time have been asked if there isn't some way we can program around a mechanical issue. "Can't you just fix it in software?"
This is the same thing, except you're trying to fix a personnel problem in software.
My advice is don't go down that rabbit hole. Fix the real problem, don't treat the symptoms.
 
We have the very same problem here, however most are not throwing away the key but they are always putting the processors into program mode, and have no idea then how to go back to run mode. The worst thing is, they are switching the key as a desperate attempt to restart the machine when troubleshooting the original cause doesn't turn up an issue that was likely related to a misaligned photo eye or a blown fuse. Sometimes I know they have been at it cause I will try to work on a system remotely only to discover that somebody has switched us to RUN instead of REM RUN.
However, when I ask who and why, it is oddly strange that nobody did it.

Ghost in the machine???


I think that mentality of switching the keys in the processors has been drilled into the older mechanics/maintenance people as that is who I generally have the problems with here. It seems like the GOTO move when all else fails.

When I express the frustration to the higher management it basically comes down to:
"Well if a mechanic or tech is at the point where we are down anyway until you get here or remote in and nobody can figure it out, what is trying the key switch going to hurt?"

:oops:
 
HMMM?

Maybe davidhinch is the problem and the electrician is trying to prevent him from making unnecessary changes.
 

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