Two of our 20 SLC500 keeps losing thier software every couple of months from an unknown reason.
the one is connected to Drives and the other to Flex I/O.

It happens after the power turned off, however - the battery is new and working fine.

any suggestions?

Nimi

 

If you manually power down the PLC's do they loose the program then?

 

Hello Nimi,

By chance do the two SLCs have EEPROM cartridges in them? If they do then what might be happening is that they are configured to load the program off of the EEPROM and the EEPROM was never programmed so there is no program to load.

Just a thought.

Bradley G. Hite
Intertech Incorporated
mailto:[email protected]
http://www.myplc.comTeaching Practical Skills for a Technological World

 

I had the same problem but it was intermittent every couple of months this would happen and the processor would fault which could only be reset by setting the processor back to default and erasing the memory. I tried other slc500 processors in the same machine but it still did the same thing. There was no DH+ connections so the only thing I thought it could be was the power.

Check your power to the plc then if that does not work get the eprom memory card and set the processor to boot off the memory card.

 

Hello List,

If there is an EEPROM memory, the problem could be in it. I faced with this mysticism. The explanation I was satisfied was a destruction
of the memory because of chaotic Vpp & Vcc falls.
The solution was to switch EEPROM Vpp from 12V to the ground(safe state) and vice
versa(programming state). Hgm...

 

No. It doesn't happen every time - I would say - evry couple of months.

 

Recently (within last 5 months)I found that there were a batch of processors that had a manufacturing problem. I misplaced the inforamtion of the range of CPU SLC500 revision affected, but I suggest calling A-B for that
info.

 

Bradley G. Hite wrote:
> By chance do the two SLCs have EEPROM cartridges in them? If they do then what might be happening is that they are configured to load the program off of the EEPROM and the EEPROM was never programmed so there is no program to load.<

I would agree with this, I had a similar problem where the PLC had an EEPROM that had one version of the logic and we loaded a new version and didn't update the EEPROM.

When the power failed the processor loaded from the EEPROM (old program).

BJ