The Plc Kid
Member
I have a several pid instructions in a slc 5/04.
Each pid is on a rung by itself and we have logic to write a zero to the cv when heaters are turned off but there is an aux contact for the main mechanical heat contact before the on/off contact both xic.
Problem with it being this way even if the heat is off but the main contactor is open it does not write a 0 to the cv so the pid is still driving.
I want to monitor when the pid is telling the heater to cycle on/off and with it this way it would tell me the pid is on even though no heating is taking place because with the main contact open power is removed from the circuit.
So i guess my main question is would it be ok to put the main contactor aux xic contact in front of the pid instruction?
Will this keep the pid from executing when the main contact is off?
Is this a good method?
Each pid is on a rung by itself and we have logic to write a zero to the cv when heaters are turned off but there is an aux contact for the main mechanical heat contact before the on/off contact both xic.
Problem with it being this way even if the heat is off but the main contactor is open it does not write a 0 to the cv so the pid is still driving.
I want to monitor when the pid is telling the heater to cycle on/off and with it this way it would tell me the pid is on even though no heating is taking place because with the main contact open power is removed from the circuit.
So i guess my main question is would it be ok to put the main contactor aux xic contact in front of the pid instruction?
Will this keep the pid from executing when the main contact is off?
Is this a good method?