Rockwell Automation MD65 User Manual Version 2.0 - Manual (Page 170)

I-2 MD65 AC Drive User Manual
• When the PID Control Loop is disabled, the Commanded
Speed is the Ramped Speed Reference.
Trim Control
In Trim Control, the PID Output is added to the Speed Reference. In
Trim mode, the output of the PID loop bypasses the accel/decel
ramp as shown. Trim Control is used when PID Ref Sel (A132) is
set to option 5, 6, 7 or 8.
Example
• In a winder application, the PID Reference equals the
Equilibrium set point.
• The Dancer Pot signal provides PID Feedback to the drive.
Fluctuations in tension result in a PID Error value.
• The Master Speed Reference sets the wind/unwind speed.
Pump
PID Feedback =
Pressure Transducer Signal
PID Reference =
Desired System Pressure
–
+
PID Prop Gain
PID Loop
PID Integ Time
PID Diff Rate
PID Enabled
Speed Ref
PID Fdbk
PID Ref
PID
Error
+
+
+
+
PID
Output
Output
Freq
+
Accel/Decel
Ramp