I recently got a 305-04b Programmable Logic Controller, and i don't know much about how to use it, so I am looking for a manual for it to help me use it and program it.
Now today, I took the individual sections out and now the programmer displays E21 on the 7-seg display. I think the E means error.
Edit: i think i found the error: E21
Program Memory Parity
Error
A parity error has occurred in the program memory of the CPU. Clear the memory
and reload the program. If the error reoccurs replace the CPU. Severe electrical noise
will cause this problem.