Howdy all
I know a guy that uses a plc5/3, if power is turned off on the machine for several days it loses the program. They have tried several batteries and have also changed the cpu card. Has anyone out there seen this problem before and have any ideas how to fix it?

==plc5/3, if power is turned off on the machine for several days it loses the program. They have tried several batteries and have also changed the cpu card. Has anyone out there seen this problem before and have any ideas how to fix it?
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Hi GaryF,
You are lucky. I have really seen that problem on the same PLC. Actually, the time that loosing the program is when power up (switched on) the PLC. The trouble makers are POWER SUPPLY and BACK PLANE. I had resoldered all the connector pins on both. Please forgive me that I can't attach the pictures showing actual location of the 'dry joints'. (As I am a poor man who can't buy a digital camera )

WBW,
Naing

Poor Solder Joints on a Quality Allen bradley Rockwell Product who would have thunk it. LOL.

Yes, sure. There are "many of dry joints" on the PCB. But I didn't mean that AB is loosing their QC. According to the machine's enveroment, I had decided to go that way to reach the solution.

Btw, my PLC lost sometimes the program when the machine was vibrating in the process, even the power was up.

WBW
Naing

Well, really Bob, you wouldn't have thunk it. Hardware malfunction is always the bottom of my troubleshooting list because A-B does 100% QC inspection, not just sample or statistical inspection. I've seen about five failed chassis in my decade with the Company, and never on a new product. Usually I shake the metal filings out or swab off the corrosion residue before continuing to troubleshoot. There are exceptions, to be sure, but bad solder joints are extremely rare.

GaryF specified a "PLC 5/3", which he doesn't actually own, see, or work on, so unless you flip a coin to decide whether he meant PLC-5/30 or SLC-5/03, we can't speculate about "I had the same problem".

If this is an SLC, there are a handful of hardware problems (backplane chip failure, auxiliary supply short-circuit) that are causing GaryF's buddy's memory failure. If it's a PLC-5 there is more likely something wrong with the battery, EEPROM, or CPU itself, because fewer backplane or installation problems can clear a PLC-5.

GaryF, more info always leads to better troubleshooting. Speculation, as always, is free.