Micrologix 1200 ERROR

Whiskey007

Member
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Join Date
Mar 2015
Location
Buckley's
Posts
13
Hi,

I am operating a Micrologix 1200 PLC whic has come up with a fault light on power up . When i go to the STATUS file under errors it says, Major Error S:6= 20h. I cleared the major error and the fault light goes off on the PLC however it does not return to RUN mode. I am in the Beginner/learning process but would appreciate any help on this ?

Thanks!
 
that error code is USUALLY caused by a math error which is trying to calculate a number larger than 32,767 ... or smaller than -32,768 ...

however it does not return to RUN mode
Click to expand...

after you've "cleared" the fault condition, to get back to the Run mode, go to the top menu and click Comms, Mode, Run ...

BUT ... chances are that you're just going to fall right back into the Fault again ...

suggestion: post your ENTIRE program file (RSS extension) ... you'll have to zip it first (forum rule) ... someone here will be able to help you solve your problem ...

here's some more detailed information - IF your problem is indeed related to the S:5/0 "overflow trap" bit ... as I said earlier, that's USUALLY (but not always) the root cause of the error code that you reported ...

http://www.plctalk.net/qanda/showthread.php?p=14230&postcount=1
 
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Thank you Ron for your response and the link to the very imformative thread especially for beginners like myself. Yes the error did read : "A minor bit is set at the end of the scan. refer to S:5 minor error bits".

I will try to upload the zipped program file tomorrow for possible further assistance in resolving the fault.
 
well, there are other "minor error bits" besides S:5/0 ... so it COULD be another one of those ... but S:5/0 is the most common culprit for giving problems ... smart money says that's the one that got you – but I wouldn't bet the rent on it ...

we'll see what we can find when you post the program ... it would be best if you could post a "faulted" version – but we'll work with what we can get ... the more you can tell us about the conditions leading up to the fault might help us nail down the problem ...

welcome to the forum ...

.

S5_0.PNG
 
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See pdf for error code 20h description.

Your program will help someone find it.
 
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A bit more information on the set up I am running . I am operating three desalination plants all running the micrologix 1200 Plc controlled by an Allen Bradley SLC 500 main controller , all three units have developed the same fault and this happened together . Could the problem be coming from the main controller?

Will send Plc the program file shortly
 
the more detail we have about the system, the more detailed help we can provide ... personally, I'd send ALL of the program files (RSS extensions) - as long as they're not considered confidential, trade-secret, or proprietary ...

basic idea: the more we know about the target - the closer we can hit to the bull's eye ...
 
I'd be suspecting those DIV instructions in File 3.

In all cases for F8:0, F8:1, and F8:2, the "trap" rung that prevents it going to zero, is after those table values are used.

If the HMI writes a 0.0 into those addresses, then the DIV instructions will all overflow.

I would swap the rung order around, put the trap rungs above the calculation rungs.
 
Also on the Ststus errors data file i noticed that Major Error Halt S:1/13 is indicating 1 . Might this have some bearing on the problem ?
When i clear the errors it goes back to 0 however the plant still wont go into run mode.
 
Not sure if it has a memory module inserted , how can i identify if it does ? please keep in mind i am only at the very beginning of trying to grasp PLC operations.....
 
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