Disappearing Logic???

Has anyone ever heard of rungs disappeaing from an AB PLC5 processor? This has happened a couple of times recently to us. One time I went to check out why a particular function of our process wasn't working and found the Lad file in RS Logix 5000 was missing all the rung logic. No other Lad files seemed to be affected. This has apparently happened to others where I work lately. Once, only part of the Lad file disappeared, everything from rung "X" down to the end of the rung was missing. Everyone here is scratching their heads on this one, so any help would be greatly appreciated.

Fer one if my memory aint totally gone then RSlogix5000 is fer the controllogix line...the PLC5 uses RSLogix5. I have seen programs corrupt but still allow access, if this has happened multiple times and you have continuosuly reloaded the program then be prepared to buy a new CPU.

I ran into that situation many years ago and they would not purchase a spare because of cost, the unit was an L40, they ended up buying a L80 for over 11000 when they could have gotten a remanufactured l40 for half that,

Live and learn.

Yeah,

We had a similar problem once whereby the PLC5 would crash in the middle of production for no apparent reason & could only be fixed by re-downloading the program.

Then some rungs went missing, which didn't help..Dunno, could have been the electrician downloading the wrong program

The problem was eventually disappeared when we changed the power supply...Always replace them first, cos they are cheaper than a processor