Dual Air-Compressor Lead/Lag

[watsonelectrical]

I'm new to plc programming but I was wondering if anyone has a sample program for a dual air compressor lead lag circuit for a SLC500. This would be activated by Wonderware and only one compressor would run at a time. If #1 Compressor is running and the pressure falls below 60psi, then #1 would cut off and #2 would come on. Also there needs to be a 5000 Hour Timer to Flip-flop the compressors and alarm for maintenance.

 

[timbo_uk]

Are you sure you want #1 compressor to knock off under 60psi (ie under large air demand). SUrely you would want both on in this condition?

 

[rsdoran]

I do not have an example but I could probably make a basic program. Provide more details, like an I/O list, and I will give it a shot. What size are the compressors? i.e. are they DOL, Wye-Delta, softstart, or VFD started? Do the compressors control their unload or will that need to be controlled? What alarms? Will the plc monitor more then line pressure?