SLC 5/03 Program Loss

seaston_65

Member
Join Date
Nov 2008
Location
Ontario
Posts
47
This morning I was called to reset a PLC fault on a SLC 5/03 (1747-L531E)
Plugging into the PLC, I realised that the PLC has lost it's program data.
I was able to download without any issue but I was surprised when I looked at the "Errors" Tab under "Processor Status" and saw that there was no battery alarm. I figured that they had the machine off all weekend, and the battery was toast and needed to be replaced.
Turns out, this machine was powered on the entire weekend. Operators/Supervisors encountered a PLC fault, cycled power, when that didn't work, contacted Maintenance.
After Downloading the program, I cycled power a few times and the PLC rebooted without issue.
I've looked through SLC 500-Instruction Set Manual and the SLC 500-Modular Hardware Style Manual, but couldn't really find anything. The Instruction Set mentioned some noise, and feedback through the powersupply, but without an Error Code, I couldn't really find anyhting. Last Major Error S:54=652h, but searching didn't find anything for that code.

Whould the Power Supply be the cause or could I have an issue with the PLC? I know I'm not giving too much info on the PLC fault, just everything I could gather. Just don't want this to be a sitting problem that happens on the weekend or night shift.

Thanks in advance for any help.

Shawn
 
As jstolaruk has mentioned, a line surge could cause program loss. Also, if you power supply is going bad you can experience this. Both conditions have caused program loss for me in the past.
 
How hard did you search?
I've got about 12 seconds invested and that includes google.

It's in the 1747-rm001_-en-p.pdf
 
S:54 652h is your error code in hex. 06 = slot 6. xx52 is the error. Check your card in slot 6. Try reseating it. I've had similar but never looked at the hex error, you could tell by the smell. The shipping loaders (future NASA engineers)snapped off a stack light and then being safety minded, stuffed the bare wires down inside the conduit--FZZZZT.
S:54 is the last error stored in S:6. If you truly believe that the memory has been cleared then S:54 should be your starting point because it's fresh.
Page B32 in the Instruction set reference.
XX52 is supposed to be a recoverable error , I'm a little confused on what AB feels recoverable means as it certainly did not resume upon clearing the error. A download was required. I think they mean you don't have to throw the entire chassis out.
 
Recoverable means that you can write a fault routine to catch the error, handle it and keep it from taking down your system with a fault.

Also, as todster mentions, having the first two digits of your error greater than zero generally means an I/O fault. You can find this fault table in the help (F1) or in the instruction manual. Fault 52 for I/O is A "module required for the user program is detected as missing or removed." Sooo if the cards there, that cant be good.
 
Last edited:
Note that if you downloaded an offline copy of the program before checking the contents of the fault registeres, then they will be invalid.

It has been my experience with the SLC that losing the program is a rare occurrence usually followed shortly by a power supply failure.

I have seen one or two that were caused by the CPU, and one or two that were caused by poor grounding.

I have also seen slot faults point to the wrong slot, but not wipe out the program. I have also seen the slot faults caused by relay cards wired to solenoids which caused noise to interfere with the backplane comms. But again, these issues have not caused me to lose the program.

Paul
 
I see this happen a lot due equipment vibration or shock by everything from plant fork trucks to operators horse playing with karate kicks.
 
... if you downloaded an offline copy of the program before checking the contents of the fault registeres, then they will be invalid.Paul

I just looked into that. I saw the new posts and took a look at my archived Programs, that fault logged in S:54 from about December.
 

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