Mitsubishi Electric FR-A720-0.4K Instruction Manual page 356

Special operation and frequency control
(2) PID action overview
1) PI action
A combination of P action (P) and I action (I) for providing a
manipulated variable in response to deviation and changes with time.
[Operation example for stepped changes of measured value]
(Note) PI action is the sum of P and I actions.
2) PD action
A combination of P action (P) and differential control action (D) for
providing a manipulated variable in response to deviation speed to
improve the transient characteristic.
[Operation example for proportional changes of measured value]
(Note) PD action is the sum of P and D actions.
3) PID action
The PI action and PD action are combined to utilize the advantages of both
actions for control.
(Note) PID action is the sum of P, I and D actions.
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Deviation Set point
Measured value
P action
Time
I action
Time
PI action
Time
Set point
Deviation
Measured value
P action
Time
D action
Time
PD
action
Time
Set point
Deviation
Measured value
P action
Time
I action
Time
D action
Time
PID action
Time