nmontev
Lifetime Supporting Member
We have a demineralizer running on a Symax 400 PLC. The PLC is connected to a Cincinatti Display serially. This system is a late 80's early 90's vintage. There are several valves that open and close based upon a specific step of a sequence.
The issue I have is I cannot find what is turning on and off bit (2500/08)= SV-10608, Rung 387. (This is just one of many valves that are not responding as desired, but I think if I understand one, I can get the rest.) I would expect something to be forcing different numbers into the 2500 series register that would correspond to the valves that should be open in a given step of the sequence. (2500/01 = SV-10601....2500/08 = SV-10608....) I cannot find anything manipulating the values of register 2500 or the individual bits for that matter.
Rung 372 contains the drum of the sequencer. The index is kept in (S2300). I have been looking here to see if anything from this is manipulating my 2500 register, and if it is, I don't understand how.
Given the problem that I can't seem to locate anything in the PLC program that is manipulating register 2500, we looked to the Cincinatti Display. The plant has found the code we believe to be in the display, and most of the items line up, i.e 903-01 of the Cincinatti Display has the same description of 903-01 in the Symax. The issue is I don't see anything referencing 2500 in the display program either.
With all of that background information, can anyone tell me what is manipulating bit (2500/08) of my program? I have attached a printed file of the Symax Code, the Cincinatti Display Code, and a spreadsheet with the expected operation of the various valves. Any direction would be much appreciated.
The issue I have is I cannot find what is turning on and off bit (2500/08)= SV-10608, Rung 387. (This is just one of many valves that are not responding as desired, but I think if I understand one, I can get the rest.) I would expect something to be forcing different numbers into the 2500 series register that would correspond to the valves that should be open in a given step of the sequence. (2500/01 = SV-10601....2500/08 = SV-10608....) I cannot find anything manipulating the values of register 2500 or the individual bits for that matter.
Rung 372 contains the drum of the sequencer. The index is kept in (S2300). I have been looking here to see if anything from this is manipulating my 2500 register, and if it is, I don't understand how.
Given the problem that I can't seem to locate anything in the PLC program that is manipulating register 2500, we looked to the Cincinatti Display. The plant has found the code we believe to be in the display, and most of the items line up, i.e 903-01 of the Cincinatti Display has the same description of 903-01 in the Symax. The issue is I don't see anything referencing 2500 in the display program either.
With all of that background information, can anyone tell me what is manipulating bit (2500/08) of my program? I have attached a printed file of the Symax Code, the Cincinatti Display Code, and a spreadsheet with the expected operation of the various valves. Any direction would be much appreciated.