Rockwell Automation 20G PowerFlex 750-Series AC Drives - Manual (Page 86)

86 Rockwell Automation Publication 750-RM002B-EN-P - September 2013
Chapter 1 Drive Configuration
Example
Display P1090 [PID Ref Meter] and P1091 [PID Fdbk Meter] as positive and
negative values. Feedback from our dancer comes into Analog Input 2 as a 0-10V
DC signal.
• P1067 [PID Ref Sel] = 0 “PI Setpoint”
• P1070 [PID Setpoint] = 50%
• P1072 [PID Fdbk Sel] = 2 “Analog In 2"
• P1068 [PID Ref AnlgHi] = 100%
• P1069 [PID Ref AnlgLo] = –100%
• P1073 [PID Fdbk AnlgHi] = 100%
• P1074 [PID Fdbk AnlgLo] = 0%
• P61 [Anlg In1 Hi] = 10V
• P62 [Anlg In2 Lo] = 0V
PI Feedback Scaling
• P675 [Trq Ref A Sel] = “Analog In 1”
• P61 [Anlg In1 Hi] = 10V
• P62 [Anlg In2 Lo] = 0V
• P1073 [PID Fdbk AnlgHi] = 100%
• P1074 [PID Fdbk AnlgLo] = 0%
Now 5V corresponds to 50% on the PID Feedback, and we try to maintain a PID
setpoint of 50% (5V).
PID Setpoint
This parameter can be used as an internal value for the setpoint or reference for
the process. If P1067 [PID Ref Sel] points to this parameter, the value entered
here becomes the equilibrium point for the process.
PID Error
The PID Error is then sent to the Proportional and Integral functions, which are
summed together.
PID Error Filter P1084 [PID LP Filter BW] sets up a filter for the PID Error.
This is useful in filtering out unwanted signal response, such as noise in the PID
loop feedback signal. The filter is a Radians/Second low pass filter.