Recently, a typical problem was encountered. In AB 5/40 installation, the power supply to the processor was to be put off for maintenance purposes. Before putting the power off it was ensured that the Battery is healthy and EPROM is also inserted properly. Upon power recycle and reboot of the processor, a different version of program came in line. This version was a one different than the one running in the processor before power recycle.

 

Hi Mihir,

I guess that your AB PLC-5/40 CPU module is installed with EEPROM that burned with default ladder logic and the backplane DIP switch 6 and 7 are set to "EEPROM transfer at every power up".

You can burn the latest program into EEPROM by online with RSLogix 5 in Program mode, from Comms menu select "Store to EEPROM"

Ikhtiander

 

Probably loaded the program from eeprom which wasn't re-burned when the program was changed... that is a manual process I believe!

Cheers from: Jeremy Pollard, CET The Caring Canuckian!
Crisis, necessity, change

 

it is almost certain that someone had failed to update the eprom to what was in the PLC and the eprom was set to load on powerup so when it powered up it loaded the old program from the eprom.

On a PLC5 I think you have to take the processor out of run mode to program the eprom so people make changes online and don't update the eprom because they would have to shutdown for a short time to do so.

--
Bob
http://ilbob.blogspot.com/