SLC5/03 wont retain program

sunnycheevah · Dec 2, 2014

Gentlemen,
So I had a SlC5/02 and EEprom wouldnt write. Upgraded to a SLC5/03 processor, with a little different 1747 eeprom. Im still getting an error. Tried permanantly writing to it and it got an error and still locked the eeprom for eternity, because I dont know what Im doing.. Everytime I lose power it instantly wipes the program, regardless of having a new battery plugged in. From what Im reading, it should keep its memory for longer than a split second. Having changed out 3 different CPUs with the same results, What is that is wrong here? Is the rack the problem?

Mickey · Dec 2, 2014

EEPROM procedure.

Try pulling the EEPROM out and see if it holds the program. With a good battery it should hold for months.

rguimond · Dec 2, 2014

Sounds to me like a bad power supply. Had the same problem a few years back. Rockwell distributor said it was a faulty PLC so we upgraded from 5/03 to 5/05 and the program wiped in less than 10 minutes. Switched power supply and it hasn't missed a beat since.

I kept the power supply for a while and was able to consistently get it to wipe programs from 500-series PLCs. Never was offered an explanation...

sunnycheevah · Dec 3, 2014

Thanks for the link and suggestion Mickey, No, it wont hold the memory in any instance. Thanks Reguimond, Ill give er a shot!
Cheers guys!

TConnolly · Dec 3, 2014

One other thing - is your chassis and power supply grounded? Not just screwed to the backpan, but bonded with a copper wire as shown in the chassis installation guide?

At our NJ plant a few years back they had three SLC5/02s that would not keep the programs through a power cycle and they asked for my help. At Rockwell's suggestion, one of the things I told them to check was grounding. After trying a number of things I finally hopped on a plane. When I got there the entire panel was still not grounded, their maintenance tech had dismissed that suggestion. I pulled in a ground wire and bonded the chassis. All three PLCs held the program through multiple power cycling tests after that.

It could still be power supply, but running a copper bonding wire first to both the chassis mounting ground tab and the power supply is a lot less money, and it should be done anyways.

Mickey · Dec 3, 2014

Do you have surge protection on all inductive loads?

GTUnit · Dec 3, 2014

Replace the Power Supply. I experienced the same ghost scenario when a SLC would occasionally just dump the program for no reason. Power supply was slowly failing.
Replaced it and all good.
I consider the PSU a "wear item" It is one part of the rack that will fail first while the rest of the components will be good for another 10 years.

sunnycheevah · Dec 4, 2014

Verified proper ground, but thats very interesting to note TCon. Not sure that I have surge protection on all inductive loads but the main is a shunt trip c/b. Ill try replacing the ps. Thanks for all your input guys!

GTUnit · Dec 4, 2014

Sunny, I think Mickey meant "Transient Suppression" or "Coil Suppression".
Surge Suppression is something different.
All contactors (inductive loads) in the panel should have a coil suppression MOV or Diode across their coil terminals.
What voltage/source feeds the SLC rack power supply?

OkiePC · Dec 4, 2014

+1 for both issues. Have seen root cause be the power supply more frequently (failed caps) and improper grounding two or three times. I have had issues with lack of surge protection on outputs cause problems too, but not a loss of program. I am sure it could happen though as others have pointed out.

sunnycheevah · Dec 4, 2014

Just a small xformer off the 480V incoming to the panel.

GTUnit · Dec 4, 2014

sunnycheevah said:
Just a small xformer off the 480V incoming to the panel.

So I am assuming 120V powers the SLC power supply. Are any large contactors in the panel and is their power coming from the same control transformer that feed the SLC Power supply?

OkiePC · Dec 4, 2014

What voltage is supplying the SLC chassis power supply?
It should be 120vac or 240vac +/- 10%
Be sure the jumper is set correctly if your supply has a voltage jumper:

http://www.***********.com/plch_images/RA-1746-P2-B-UPP_b.jpg not the best picture, the logo is hiding the actual jumper right under the "a" character...

I have seen one set incorrectly to 240vac (new out of the box position) and still work for several days when the incoming voltage was about 130vac! Then one day it decided not to light up at all after a power cycle. That machine had a memory module installed and it did load and run...

sunnycheevah · Dec 4, 2014

Its a 1000kva 120V transformer with about a dozen 10A contactors(coils) coming off as well as the slc. The panel was engineered with the loadformer from factory in the early 90s. To my knowledge nothing was changed.

OkiePC · Dec 4, 2014

I think you meant 1kva or 1000va since earlier you said small transformer, but in any case, that is unlikely to be the problem, but the SLC chassis power supply is where I would start if I were in your shoes, assuming you have a spare or can get one.

SLC5/03 wont retain program

sunnycheevah

Member

Mickey

Lifetime Supporting Member

rguimond

Lifetime Supporting Member

sunnycheevah

Member

TConnolly

Lifetime Supporting Member

Mickey

Lifetime Supporting Member

GTUnit

Member

sunnycheevah

Member

GTUnit

Member

OkiePC

Lifetime Supporting Member

sunnycheevah

Member

GTUnit

Member

OkiePC

Lifetime Supporting Member

sunnycheevah

Member

OkiePC

Lifetime Supporting Member

Similar Topics