YASKAWA VARISPEED-616G5 - Types of PID Control; Feedback Value

7.5 Common Functions
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Deviation
Time
Control input
D control
PID control
I control
P control
Time
Fig 7.23 PID Control Operations
D P Control: A control input proportional to the deviation is output. The deviation cannot be zeroed
by P control alone.
D I Control: A control input which is an integral of the deviation is output. This is effective for
matching the feedback to the target value. Sudden changes, however, cannot be fol-
lowed.
D D Control: A control input which is an integral of the deviation is output. Quick response to sud-
den changes is possible.
D PID Control: Optimum control is achieved by combining the best features of P, I, and D control.
Types of PID Control
Two types of PID control are possible with the Inverter: Measured-value derivative PID control and basic
PID control. The type that is normally used is measured-value derivative PID control.
D
Measured-value Derivative PID Control:
With measured-value derivative PID control, the feedback value is differentiated for PID control. Re-
sponse is possible with respect to changes both in target values and the control object.
Feedback value
Target value
P
I
D
Control object
−
+
+
+
+
+
D
Basic PID Control: This is the basic form of PID control. When the D control response is adjusted
to follow changes in the control object, overshooting and undershooting can oc-
cur with changes in the target value.
Feedback value
Target value
P
I
Control object
−
+
+
++
D
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