Akbrewer
Member
Hi,
I have a SLC 5/04 processor, model 1747-L541 that had the backup battery fail a few weeks ago because we didn't see the BAT light on it in time, so we lost the program. I saw the FLT light when this happened, so I replaced the battery and then had to reload the program. At the time I didn't think to test the processor to make sure it wouldn't lose the program again, the BAT light went away and the program reload was happy.
Everything was running fine until last week when we had a power outage and again the processor lost the program. When the power came back on, I had a FLT light and no program on the processor. This time there were no battery issues. So I reloaded the program, but this time I tested the processor by shutting off power to it. It loses the program and gives me a FLT light. If I try to get online with the processor I get the NVRAM error code of 0001H. In looking at other forum posts, this sounds like a power supply issue but we haven't made any changes to this processor in years and until the battery went dead, we've never had a problem with it.
I have not been able to keep the processor from losing the program, so I installed an EEPROM chip on the processor. I've done this in the past and typically set up the processor EEPROM bit to reload from EEPROM only if there is a memory fault. But no luck, the processor would still lose the program and I'd have to get online with my computer and then reload from the processor EEPROM. I finally set up the processor so it always loads from the memory chip on reboot and that has fixed the problem for now, but its not a long term solution. This PLC stores user inputted ingredient names from an HMI onto the processor and assigns them to a group of silos that we have. We frequently move the ingredients in each of the silos or change ingredient names, so now if the old EEPROM program reloads after a power outage we may find that we have the wrong ingredients listed or have them shown in the wrong silo.
So today, I took a spare 5/04 processor that I had (model 1747-L542C) and installed it. I left off the EEPROM chip figuring I would be safe with the newer processor. To my surprise, the spare 5/04 processor had the same issue and is also losing the program and giving me a FLT code any time I cycle the power to the unit.
Short of checking the power supply module or replacing the rack, does anyone have any idea what might be happening or why this would suddenly start happening to both processors? I don't have any program errors that show up when I check the program, so I don't think it's a faulty program or incompatibility issue.
Thanks for any ideas in advance!
Cheers,
Curtis Holmes
I have a SLC 5/04 processor, model 1747-L541 that had the backup battery fail a few weeks ago because we didn't see the BAT light on it in time, so we lost the program. I saw the FLT light when this happened, so I replaced the battery and then had to reload the program. At the time I didn't think to test the processor to make sure it wouldn't lose the program again, the BAT light went away and the program reload was happy.
Everything was running fine until last week when we had a power outage and again the processor lost the program. When the power came back on, I had a FLT light and no program on the processor. This time there were no battery issues. So I reloaded the program, but this time I tested the processor by shutting off power to it. It loses the program and gives me a FLT light. If I try to get online with the processor I get the NVRAM error code of 0001H. In looking at other forum posts, this sounds like a power supply issue but we haven't made any changes to this processor in years and until the battery went dead, we've never had a problem with it.
I have not been able to keep the processor from losing the program, so I installed an EEPROM chip on the processor. I've done this in the past and typically set up the processor EEPROM bit to reload from EEPROM only if there is a memory fault. But no luck, the processor would still lose the program and I'd have to get online with my computer and then reload from the processor EEPROM. I finally set up the processor so it always loads from the memory chip on reboot and that has fixed the problem for now, but its not a long term solution. This PLC stores user inputted ingredient names from an HMI onto the processor and assigns them to a group of silos that we have. We frequently move the ingredients in each of the silos or change ingredient names, so now if the old EEPROM program reloads after a power outage we may find that we have the wrong ingredients listed or have them shown in the wrong silo.
So today, I took a spare 5/04 processor that I had (model 1747-L542C) and installed it. I left off the EEPROM chip figuring I would be safe with the newer processor. To my surprise, the spare 5/04 processor had the same issue and is also losing the program and giving me a FLT code any time I cycle the power to the unit.
Short of checking the power supply module or replacing the rack, does anyone have any idea what might be happening or why this would suddenly start happening to both processors? I don't have any program errors that show up when I check the program, so I don't think it's a faulty program or incompatibility issue.
Thanks for any ideas in advance!
Cheers,
Curtis Holmes