SLC503 losing program when powered down

scottsull · Jan 8, 2007

About 6 weeks ago when power to the PLC was shut off for about
20 minutes the program in memory was lost. At that time we installed a new battery, downloaded the program to the PLC and all was OK.

Three weeks ago power was lost to the PLC again and the program in memory was again lost. At this time a new SLC503 (factory new with battery installed)was installed, a four hour UPS was installed and the program was downloaded. All was OK until this weekend when power was again turned off to the PLC circuit. I just got a call stating that when a startup was just attempted the PLC has once again lost the program in memory.

What besides a dead battery would cause a PLC which is running fine to lose the program in memory when the power to the PLC is shut off? These were all normal shutdowns with power to the PLC
shut off for maintainance work on AC circuits having nothing
to do with the PLC.

Any help is appreciated.

rPraveenkum · Jan 8, 2007

check mainly the gounding for the slc power supply & I will suggest to use of EEprom module to hold the program & restore the same during memory corrupt.

jeepmudman · Jan 9, 2007

I had the same thing going on. It ended up being the power supply was bad. when the power was shut off it spiked the proccesor.

TConnolly · Jan 9, 2007

Check your grounding.

Our NJ plant lived with this problem for years. Everytime the power went off they reloaded the program and *****ed about AB. They tried everything except following the manufacturers grounding requirements. After we aquired them, I flew out once and told them to properly ground the system. Viola. Problem solved.

TSmith · Jan 10, 2007

Had exact same problem. New power supply fixed problem

curlyandshemp · Jan 10, 2007

scottsull said:
About 6 weeks ago when power to the PLC was shut off for about
20 minutes the program in memory was lost. At that time we installed a new battery, downloaded the program to the PLC and all was OK.

Three weeks ago power was lost to the PLC again and the program in memory was again lost. At this time a new SLC503 (factory new with battery installed)was installed, a four hour UPS was installed and the program was downloaded. All was OK until this weekend when power was again turned off to the PLC circuit. I just got a call stating that when a startup was just attempted the PLC has once again lost the program in memory.

What besides a dead battery would cause a PLC which is running fine to lose the program in memory when the power to the PLC is shut off? These were all normal shutdowns with power to the PLC
shut off for maintainance work on AC circuits having nothing
to do with the PLC.

Any help is appreciated.

We had this happen randomly at a cutsomers' site after water started dripping onto the SLC's rack and power supply from a conduit coming into the top of the panel.

Replacing Rack and P.S. solved the problem, and water damage was evident on both the rack and P.S.

Ian

doug2 · Jan 10, 2007

buy an eeprom

scottsull · Jan 11, 2007

Thanks all

Jeepmudman,TSmith and CurlyandShemp all hit it right on the head!

Changed out power supply and all works as it should now.

Thanks to all for the assistance.

SLC503 losing program when powered down

scottsull

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rPraveenkum

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jeepmudman

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TConnolly

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TSmith

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curlyandshemp

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doug2

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scottsull

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