M-12
3 Parameter
FX
3G
/FX
3U
/FX
3UC
PLC User's Manual - Analog Control Edition
PID Instruction (FNC 88)
3.2 Details of Parameters
3.2.3 Input filter (α): (S3)+2
Setting range: 0 to 99[%]
PID control: Proportional operation, integral operation and differential operation
The input filter (α) is a software filter to reduce the fluctuation of the measured value (PV) caused by noise.
By setting this time constant of the filter according to the control target characteristics and noise level, the
effect of noise can be reduced.
• If the input filter value is too small, the filter effect is small.
• If the input filter value is too large, the input response is bad.
Because the input filter (α) is effective to the target value (SV), all of the proportional operation, integral
operation and differential operation are affected.
Input amplitude
Input amplitude
processed by input filte
r
Pulse input by noise
Actual
measured
value (PV)
Measured
value (PV)
processed by
input filter