7 APPLICATION INSTRUCTIONS
7.18 PID Instruction
737
7
Proportional gain (K
P
): (S3)+3
Setting range: 1 to 32767[%]
PID control: proportional operation
The manipulated value (MV) increases in proportion to the error (difference between the set value (SV) and process value
(PV)) in the proportional operation. This proportion is called the proportional gain (K
P
) and is expressed in the following
relational expression.
Manipulated value (MV) = Proportional gain (K
P
) error (EV)
The reciprocal of the proportional gain (K
P
) is called the proportional band.
As the proportional gain (K
P
) increases, the movement of getting the process value (PV) closer to the set value (SV) will be
stronger.
Proportional operation (P operation) in heating (reverse action)
Proportional operation (P operation) in cooling (direct action)
KP3 > KP2 > KP1
KP3 > KP2 > KP1
KP3 KP2 KP1
KP3
KP2
KP1
SV
PV
Residual error
Proportional gain
Time
Time
Proportional gain
MV
Temperature
K
P3
> K
P2
> K
P1
K
P3
> K
P2
> K
P1
K
P3
K
P2
K
P1
K
P3
K
P2
K
P1
SV
Time
Time
PV
Proportional gain
Proportional gain
MV
Residual error
Temperature
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