RoTaTech
Member
Has anyone here a lead on monitoring AC current? We are rebuilding a machine that has approx. 70 heater zones, and in the past, each has been monitored with a CT and an analog panel meter. The various zones draw 12 to 30A at 240VAC.
I would like a system to read the CTs into analog channels so we can do burnout detection and stuck contact detection. The current Siemens 505 PLC does not have room for 70 analog channels. It can be stand-alone with its own panel display to emulate the 70 gauges, or it could feed over Profibus to our PLC.
We have a few conditions that I want to be able to react to:
Heater burnout - no current when there should be; stuck output (current when there should not be; I can turn off the master Heat control circuit); stuck contactor (current when there should not be; I can turn off the master Heat power circuit with a shunt trip breaker). The panel meter at present require someone to notice; I want to be preemptive and catch the faults to annunciate status.
I would like a system to read the CTs into analog channels so we can do burnout detection and stuck contact detection. The current Siemens 505 PLC does not have room for 70 analog channels. It can be stand-alone with its own panel display to emulate the 70 gauges, or it could feed over Profibus to our PLC.
We have a few conditions that I want to be able to react to:
Heater burnout - no current when there should be; stuck output (current when there should not be; I can turn off the master Heat control circuit); stuck contactor (current when there should not be; I can turn off the master Heat power circuit with a shunt trip breaker). The panel meter at present require someone to notice; I want to be preemptive and catch the faults to annunciate status.