Hi i have a ad 5 hp VFD running a submersible water pump. I want to control pump speed to maintain constant pressure using a pressure transducer. the problem i have is when the pressure goes up the VFD speeds up the pump, How can i reverse this so the pump slows down as the presure goes up
constant presure control
- Thread starter Waldg
- Start date
widelto
Member
You must reverse your PID operation, there are two ways one is using Error=PV-SP, second option is to use a scale to invert PID output.
TConnolly
Lifetime Supporting Member
Configure your PID as reverse acting. Because a PID responds to error between the setpoint and the process variable, when pressure is below setpoint error has to be positive to increase the control variable, or SP-PV.
balash
Member
or maybe your VFD is set to direct torque control (open loop). then you need to set it to closed loop control and set PID as stated above...
EDIT:
Also, check if input to VFD is set as feedback or reference... it should be feedback
EDIT:
Also, check if input to VFD is set as feedback or reference... it should be feedback
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