Mitsubishi Electric MELSEC iQ-R Series - Page 1141

9 PID OPERATION INSTRUCTION
9.1 Overview
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Input filter: (s3)+2
Setting range: 0 to 99 [%]
PID control: Proportional action, integral action, derivative action
The input filter () is a software filter used to reduce the variations caused by noise in the process value (PV). The influence of
noise can be suppressed by setting the input filter () properly according to the characteristics and noise level of the control
target.
• If the filter coefficient is too small, the effect will be reduced.
• If the filter coefficient is too large, the input response will deteriorate.
The input filter () acts on the set value (SV) and thus affects the proportional action, integral action, and derivative action.
Proportional gain: (s3)+3
Setting range: 1 to 32767 [%]
PID control: Proportional action
The manipulated value (MV) increases in proportion to the deviation (difference between the set value (SV) and the process
value (PV)) in proportional operation. This ratio is called the proportional gain (K
P
) and represented by the following relational
expression.
Manipulated value (MV) = Proportional gain (K
P
)  Deviation (EV)
The reciprocal of the proportional gain (K
P
) is called the proportional band.
As the proportional gain (K
P
) increases, the motion to get the process value (PV) closer to the set value (SV) becomes strong.
Ex.
Proportional action (P action) in the case of cooling (direct action)
Actual process
value (PV)
Filtered process
value (PV)
Proportional gain (K
P
): K
P3
> K
P2
> K
P1
: Temperature
SV: Set value
PV: Process value
MV: Manipulated value
t: Time
Pulse input due to noise
Amplitude of input
Amplitude of filtered input
K
P3
K
P2
K
P1
K
P3
K
P2
K
P1
MV

SV
PV
t
t
Remaining deviation