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Trim control – Rockwell Automation 22D PowerFlex 40P User Manual, FRN 3 User Manual

Page 183

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PID Set Up

G-3

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

A132

[PID Ref Sel] is set to option 6,

7, 8, 9 or 10.

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.

As tension increases or decreases during winding, the Speed
Reference is trimmed to compensate. Tension is maintained near the
Equilibrium set point.

+

PID Prop Gain

PID Loop

PID Integ Time

PID Diff Rate

PID Enabled

P038 [Speed Reference]

PID Fdbk

PID Ref

PID

Error

+

+

+

+

PID

Output

Output

Freq

+

Accel/Decel

Ramp

P038 [Speed Reference]

0 Volts

PID Feedback =
Dancer Pot Signal

10 Volts

PID Reference =

Equilibrium Set Point