SLC in fault after powerup

nileshsurya · Apr 6, 2005

hi thr u all plc experts
recently i came across with 2-3 SLC systems in which one typical problem was there

when the SLC is cycle powered it directly goes into fault mode,it should go into run mode but it doesnt.it is then bought into run mode by switching the key

what must be the probable cause for this and what is the suggested remedy, can anybody tell plz
can the status bit fault override at powerup be set to solve this problem
i am also desperatley looking for the probable cause of this problem

waiting for reply ASAP

regards
NileshSURYA

mordred · Apr 6, 2005

which fault? can you go online with it and get the fault code that will help in helping you

davidg68124 · Apr 6, 2005

Are you saying the Fault light is flashing? Or it just does not go into run mode unless you use the key.

If the latter is the case then the bit in the status file for it to goto run after powerup is not set.

Or another possibility I suppose, could be a math overflow during startup. I believe you can switch to run mode for that to clear, but I am not sure off the top of my head.

Both of these would require you have logix and go online in order to determine what the actual cause is. Do you have access to that?

David

stasis · Apr 6, 2005

go online with a PC & check the fault...in RS500, the fault will be highlighted under the "edits" drop-down menu. Double-click the fault & it will tell you what type of fault you're having...

504bloke · Apr 6, 2005

If you can acces the processor using Logix 500 then this may help

leitmotif · Apr 7, 2005

When this happened to me, my instructor pointed out that I had not yet configured it and told the CPU what cards were installed. This was on a Allen Bradley SLC 5/05. Simple solution to what seemed like a complex problem. I guess that is the way it is when you are learning

Dan Bentler

jolio ST · Apr 7, 2005

Yes. I agree with Dan Bentler. The most common and mainly the first problem I will check is if the CPU is configured correctly. even an additional rack installed when there isn't, or wrongly assigned modules may trigger faults.

regards
Sherine T.

davidg68124 · Apr 7, 2005

An incorrect Configuration would not allow the processor to go into run mode.

There is some other problem here.

David

leitmotif · Apr 7, 2005

Well he said

when the SLC is cycle powered it directly goes into fault mode,it should go into run mode but it doesnt.it is then bought into run mode by switching the key

That was the same exact problem I had which was cured by correctly configuring. Like he says it powerd up then went direct to fault

Dan Bentler

davidg68124 · Apr 7, 2005

You were able to put the processor in run mode with the key switch BEFORE you cured the configuration problem? Or after.

I read it as all he has to do is switch it to run and it is fine. If there is a configuration problem, it would immediately fault again.

David

OkiePC · Apr 7, 2005

I've had one SLC5/04 that would do this. It also would go from run mode to program mode all by itself about once every 12 hours! We replaced the procesor to fix it, and I never did check the processor status table...PC

504bloke · Apr 7, 2005

If it isnt configured correctly and you have problems with logix then these pics might help

SLC in fault after powerup

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