Mitsubishi MELSEC-F FX3U Series User Manual

G-10
3 Parameter
FX 3U /FX 3UC Series PLC User's Manual - Analog Control Edition
PID Instruction (FNC 88)
3.2 Details of Parameters
3.2.2 Operation setting (ACT):(S3)+1
Setting range: OFF = forward operation, ON = backward operation
1. Forward operation or backward operation: +1, bit 0
Select the PID control direction (forward or backward).
• In the auto tuning (limit cycle method)
It is necessary to set the PID control direction (forward or backward) of auto tuning.
• In the auto tuning (step response method)
Without regard to the setting of the PID control direction (forward or backward), the direction is
automatically set when auto tuning is completed.
Forward operation: +1, bit 0 = 0
As the measured value (PV) becomes larger than the target value (SV), the output (MV) increases.
For example, cooling is a forward operation.
<Cooling>
Backward operation: +1, bit 0 = 1
As the measured value (PV) becomes smaller than the target value (SV), the output (MV) increases.
For example, heating is a backward operation.
<Heating>
Relationship between the forward/backward operation and the output (MV), measured value (PV) and
target value (SV)
The relationship is as follows.
S 3
S 3
Time
Target value (SV)
Measured value (PV)
Temperature
S 3
Time
Target value (SV)
Measured value (PV)
Temperature
Output (MV)
Backward
operation
Target value (SV)
Forward
operation
Measured value (PV)

Mitsubishi MELSEC-F FX3U Series Specifications

General

Brand	Mitsubishi
Model	MELSEC-F FX3U Series
Category	Controller
Language	English