Working from my memory of late last week. When watching the programs on line, towards the bottom of the ladder, there is a bunch of moves and multipies. I remember lots of MOV instruction which contained DM32. (Think it was shown as D0032 in the LSS program.) I only remember seeing zeros for the values. Other than a couple multiplies, which had values, like in the 1000s, the D00xx values were all zero. That did strike me as odd. (I don't see this in the program, viewing it offline from here at home. Does the program, when online with the processor, show the actual or current values to the right of the ladder diagram?)
I may or may not understand the part of the EPORM being damaged. When I put the EPROM in the bad PLC (one I need to replace), the press acts normal, with one exception, the foot input which appears to be shorted on, thus I can not inch the press. I put the same EPROM in 2 other PLCs, I get one single stroke in inch mode. Wouldn't a damaged EPROM give like symptoms in all 3 PLCs?
In inch mode, most of the machines programmed in safety features are bypassed. Two of which (I believe) are the brake monitor and I also believe the redundancy cheking that it accomplishes with the assistance of a separate Omron delay timer.
The redundancy checking with external Omron delay timer works with output 102 of the PLC pulsing the control or reset on the Omron delay timer, which in turn energises input 011 on the PLC.
The brake monitor counting prox (Input 000) should be counting 40 teeth on a cogged disk on the crank. The press is supposed to (and does) stop at about 4 teeth, after the reset prox (input 001) tells it to stop at TDC. If the crank over rotates, the brake monitor faults out and the PLC flashes one of the outputs (104, nothing wired to it), to indicate a brake monitor fault.
To initiate a stroke in single stroke mode, inputs 006, 008, 009 & 010 need to be on. I believe output 102 starts pulsing the redundance timer at the same time outputs 100 and 101 (dual solenoid valve) energises. OOPS, the stroke is initiated by energizing inputs 002 & 003. These are the 2 palm buttons, which must be made with in a few hundredths of a second of each other.
As far as In know, to make a stroke in inch mode, inputs 005, 008, 009 and 010 need to be on before pressing the palm buttons.