Rockwell Automation 22C PowerFlex 400 AC Drive FRN 1.xx - 7.xx User Manual
Page 179
Application Notes
D-3
PowerFlex 400 Adjustable Frequency AC Drive FRN 1.xx - 7.xx User Manual
Publication 22C-UM001I-EN-P
Exclusive Control
In Exclusive Control, the Speed Reference becomes 0, and the PID
Output becomes the entire Freq Command. Exclusive Control is used
when
[PID Ref Sel] is set to option 1, 2, 3 or 4. This configuration
does not require a master reference, only a desired set point, such as a
flow rate for a pump.
Example
•
In a pumping application, the PID Reference equals the Desired
System Pressure set point.
•
The Pressure Transducer signal provides PID Feedback to the drive.
Fluctuations in actual system pressure, due to changes in flow, result
in a PID Error value.
•
The drive output frequency increases or decreases to vary motor
shaft speed to correct for the PID Error value.
•
The Desired System Pressure set point is maintained as valves in the
system are opened and closed causing changes in flow.
•
When the PID Control Loop is disabled, the Commanded Speed is
the Ramped Speed Reference.
–
+
PID Prop Gain
PID Loop
PID Integ Time
PID Diff Rate
PID Enabled
PID Fdbk
PID Ref
PID
Error
+
+
+
PID
Output
Accel/Decel
Ramp
Freq
Command
Pump
PID Feedback =
Pressure Transducer Signal
PID Reference =
Desired System Pressure