PM'd AB question

I received this question in a PM:

If he can still go online with the faulty SLC, then there is a chance that the program is still in the memory, he should then be able to upload it.
There are both serial and DH+ ports on the SLC5/04, so he could attempt to access both.

If that is not possible, then maybe the original programmer installed an EPROM in the faulty SLC. Simply moving the EPROM to the new SLC should do the trick.

edit: After a little thought about it, I think that the original poster does not have RSLogix500. His best option is to send the defective SLC to AB and ask them to try and salvage the program.

Well,
What do you mean by faulty? The problem could be that your current processor has "lost" it's programming. If that's the case buying a new processor will not solve your problem. Depending on the condition of your existing processor, you may or may not be able to upload the current program.

To upload an existing program, you will need software and cables.
These are quite expensive. I would suggest contacting your AB dealer, they will be able to help you retrieve you old program and load the new processor. An alternative would be a local programming house that already has the software.

edit: Jesper's last suggestion may be the best one.

On a completely different note:
The problem may well be in the rack or an i/o module.
The CPU will indicate "fault" and refuse to run. So getting a new CPU and moving the program to the new CPU may not solve the problem.

What is the status of the LEDs on the CPU ?

I once had a problem with a SLC 5/04 fitted with an EEPROM, it was faulting and reloading the program from EEPROM did not fix it. When I re-loaded the program from my laptop and also copied the re-loaded program to the EEPROM then the fault disappeared. Still not sure what was wrong but I think it must have been a corrupted program in the CPU and the EEPROM. The CPU had been shut down for maintenance and the battery was OK. Any Ideas?

no comms = no problem identification ??

If he is unable to "talk" with PLC ie connect to computer to see what is in the program or what the program is doing how does he know if the problem is software or hardware. Which is why some have recommended he get vendor to check unit out. Also is it not possible some sensor has failed that is the root cause of problem??

Dan Bentler

how does he know if the problem is software or hardware.

Click to expand...

If the "FLT" LED on the CPU is constantly lit, or the POWER LED is lit while no LED is lit on the CPU, then most likely the CPU is defective.

If the "FLT" LED flashes, then there is "Major fault" that can be caused by the CPU, a programming fault, the rack, or the i/o. So if "FLT" flashes, then there is a good chance that the CPU is not defective, and the fault must be found elsewhere.