Mitsubishi FR - S500 Instruction Manual page 112

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.
REMARKS
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.
REMARKS
The 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 -
process value) is positive,
and decreases the
manipulated variable if
deviation is negative.
[Operation example for proportional changes
of process value]
P action
D action
PD action
P action
I action
D action
PID action
[Heating]
+
Set point
-
Feedback signal
(Process value)
Cold up
Hot down
103
Set point
Deviation
Process
value
Time
Time
Time
Set point
Deviation
Process
value
Time
Time
Time
y=at +bt+c
Time
X>0
X<0
Set point
Deviation
Process value
2
2