Controlling 2-8 degree C Walk-In Refrigerator
Controlling 2-8 degree C Walk-In Refrigerator
(OP)
I am interesting in controlling a 2-8 degree C Walk-In Refrigerator using a PLC. I have two compressors that are configured for master/ slave. Compressor comes on when temperature in Walk-In is Out of Spec (2-8). Also, every 3.5 days the master/ slave (lead/ lag) configuration changes. We currently have a Honeywell 4500 Chart Recorder Controller with external relays that's having problems. Any suggestions?





RE: Controlling 2-8 degree C Walk-In Refrigerator
http://www.flaminsystems.com/page/page/2456297.htm
If you want to do that with the PLC I would ditch the 3.5 day thingy. Run two totalizers, one for each compressor. Whenever cooling is called for you turn on the compressor with the lowest totallizer time. The two compressors then play leap-frog from then on, always tending towards equal run times. Works great.
RE: Controlling 2-8 degree C Walk-In Refrigerator
RE: Controlling 2-8 degree C Walk-In Refrigerator
What specific problem(s) are you having?