Mitsubishi Electric FR-D700 Instruction Manual page 213

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.
4)Reverse operation
Increases the manipulated variable (output frequency) if deviation X = (set point - measured value) is positive, and
decreases the manipulated variable if deviation is negative.
Set point
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.
Set point
Relationships between deviation and manipulated variable (output frequency)
Positive
Reverse action
Forward action
[Heating]
+ X>0
X<0
-
Feedback signal
(measured value)
[Cooling]
+ X>0
Too cold
X<0
Hot
-
Feedback signal
(measured value)
Deviation
Negative
Special operation and frequency control
P
action
I action
D action
PID action
Deviation
Cold
Increase
Hot
Decrease
Measured value
Decrease
Increase
Deviation
Set point
Deviation
Measured value
Time
Time
Time
2
y=at +bt+c
Time
Set point
Measured value
Set point
4
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