Slc 5/05 eeprom

I have a SLC 5/05 and I am sure it has an EEPROm installed but when online with the processor it will not let me load the latest program to the EEPROM so does it have to be in program mode to do this? If so why?

The machine it's on is really tough to shut down and get line down time on.

Yes, unfortunately it has to be in program mode. Why? I am not sure. When you go into program mode you will go to Tools > EEPROM > Save to EEPROM or something similar to that. I don't have a program open right now so I can't double check.

It prevents people from “accidently” loading a program into the PLC. The key has three positions, Run, Run/Program and Program. The Run position will not let you download at all, the Run/Program position lets you program the PLC without having to change the switch position but you have to respond to prompts to take the PLC out of run mode and to put it back into run mode after the download. The Program position will not let you change the PLC back to run mode without moving the key to prevent accidental operation. This is what you would use if the PLC is controlling a process that can do damage or cause injuries and you don’t want it to run until you know you are completely ready. Most people leave the key in the Run/Program position and use RSLogix to start/stop the processor.