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MELSEC-Q
1 GENERAL DESCRIPTION
1.3.2 The Q62HLC actions
The Q62HLC performs PID operations in reverse action and forward action.
(1) Reverse action
In a reverse action, the process value (PV) increases toward the set value (SV)
as the manipulation value (MV) increases.
The reverse action is effective for heat control.
(2) Forward action
In a forward action, the process value (PV) decreases toward the set value (SV)
as the manipulation value (MV) increases.
The forward action is effective for cooler control.
Forward action
(when used for cooling control)
Reverse action
(when used for heat control)
Process value
Time
Set
value
Temperature
Temperature
Set
value
Time
Process value
Fig. 1.6 Process control example in reverse action and forward action