RSLOGIX 5000 PID Instruction

[RiverAmy 0]

Hello, I'm trying to control some VFD's (Variable frequency drives) using a PID instruction in my RSLogixs5000. I have an Actual Flow Rate (feed back) and a Set Point. the problem I'm having...I'm not sure how to send the output of the PID to my VFD's. I'm communicating with DeviceNet (1756-DNB). Do I need to Covert my answer then output it to the VFD's. For example, I know my pump capacity is 0 to 1200 gpm. Do I need to convert that to another number like FOR EXAMPLE, 3277 to 16384? I had a card that required that once for a 4 to 20mA signal. Oh, I'm using PowerFlex 700 (if that helps). I'm using a scheduled routine for every 250 ms. I have a MOV instruction that takes my requested Set Point to VFD.SP then i have the PID instruction following my Process Variable = Actual Flow Rate (my feedback) and the Control Variable = is a newtag I call Speed ....Now I'm stuck If you need more info. just let me know Thanks for your help, Amy

[TimWilborne 108]

I have never used the Powerflex on Devicenet but most drives I have used on Devicenet require a Command Frequency with reference to Hz. You say 0-1200 GPM on your pump. Is that with a frequency of 0-60Hz? Usually 0-60Hz is 0-1800 RPM but need more info on the motor to be sure. It should say on it

[AutomationWizard 0]