Application Notes D-3
Exclusive Control
In Exclusive Control, the Speed Reference becomes 0, and the PID
Output becomes the entire Freq Command. Exclusive Control is used
when A152
[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
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