Mitsubishi Electric FR-A700 Technical Manual page 370

(2) PID action overview
1) PI action
A combination of proportional control action (P)
and integral control action (I) for providing a
manipulated variable in response to deviation and
changes with time.
PI action is the sum of P and I actions.
2) PD action
A combination of proportional control action (P)
and differential control action (D) for providing a
manipulated variable in response to deviation
speed to improve the transient characteristic.
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.
PID action is the sum of P, I and D actions.
4) Reverse action
Increases the manipulated variable (output frequency) if deviation X = (set point - measured value) is positive, and
decreases the manipulated variable if deviation is negative.
5) Forward action
Increases the manipulated variable (output frequency) if deviation X = (set point - measured value) is negative, and
decreases the manipulated variable if deviation is positive.
Relationships between deviation and manipulated variable (output frequency)
Reverse action
Forward action
[Heating]
+ X>0
Cold
Set
X<0 Hot
point
-
Feedback signal
(measured value)
[Cooling]
X>0
+
Too cold
Set
X<0 Hot
point
-
Feedback signal
(measured value)
Deviation
Positive Negative
P action
I action
PI action
P action
D action
PD action
P action
I action
D action
PID action
Deviation
Increase
Decrease
Measured value
Measured value
Decrease
Increase
Deviation
404
PARAMETER
Deviation Set Point
Measured value
Time
Time
Time
Set Point
Deviation
Measured
value
Time
Time
Time
Set Point
Deviation
Measured
value
Time
Time
Time
Time
Set point
Set point