I've got a medium temp rack with an Emerson e2 controller (RX-300), 7 circuits with eepr (stepper valves) controlled by case temperature. The problem I was having was the compressors were cycling about 300 times a day. Started checking things and found that my eepr valves wouldn't balance out. They would run wide open until about 2* before target then go to about 60%. Once it hit target it would go to 0%. There were times all but one circuit would be at 0%. I got to looking at my settings and found that somebody had changed the P.I.D. settings. I set them back to default (I think) P-gain=1.00 I-gain=0.30 D-gain=0.00 P.I.D. deadband=0.10. Now eepr valves are regulating like they should which balanced out load on rack and got compressor cycle rate down to around 20 times a day. My question is what does each of the P.I.D. settings do?
hvacrdrew
Make sure the controller is set up for the correct brand of EEPR (Sporlan, Emerson, Danfoss), and the correct maximum number of steps that the valve has.
Also, the controller never really knows what position the valve is at. It assumes that if it drives the valve to 50%, that it's actually at 50%. Problems can arise when the valve position is out of sync with where the controller thinks it is.
Also, the controller never really knows what position the valve is at. It assumes that if it drives the valve to 50%, that it's actually at 50%. Problems can arise when the valve position is out of sync with where the controller thinks it is.
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