Mitsubishi Electric 800 Series Instruction Manual page 492

• PID action
PID action is a combination of PI and PD action, which enables control that
incorporates the respective strengths of these actions.
(Note) PID action is the result of all P, I and D actions being added together.
• Reverse action
When deviation X = (set point - measured value) is a plus value, the manipulated amount (output frequency) is increased, and
when the deviation is a minus value, the manipulated amount is decreased.
Set
point
• Forward action
When deviation X = (set point - measured value) is a minus value, the manipulated amount (output frequency) is increased,
and when the deviation is a plus value, the manipulated amount is decreased.
Set
point
Relationship between deviation and manipulated amount (output frequency)
PID action setting
Plus
Reverse action
Forward action
[Heating]
+ X>0
Cold
Hot
X<0
-
Feedback signal
(measured value)
[Cooling]
X>0
+
Too cold
X<0 Hot
-
Feedback signal
(measured value)
Deviation
Minus
(A) Application parameters
P action
I action
D action
PID action
Deviation
Increase
Decrease
Measured value
Measured value
Decrease
Increase
Deviation
Set point
Deviation
Measured value
Time
Time
Time
Time
Set point
Set point
491
PARAMETERS
5
GROUP
A