10 PID CONTROL FUNCTION
10.6 Details of Parameters
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The ramp value is obtained with the following formula.
Ramp value = (current input value - previous input value) ÷ sampling time
If the hunting suppression setting is not used, the PID control operation with similar performance to the FX3
PLC will be executed.
Input filter constant (s3)+2
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. Setting
range: 0 to 99 (%).
Because the input filter (α) acts on the target value (SV), all of the proportional operation, integral operation and differential
operation are affected.
(1) Timeout wait after maximum ramp detection
(2) A decrease of ramp caused by temporary deviation of the input
value
(3) Maximum ramp (R) is updated so that auto tuning continues
(4) Timeout wait after maximum ramp detection
(5) Maximum ramp (R) detection value at the end of auto tuning
(6) Maximum ramp (R) detection value at the end of auto tuning
when this setting is not used
Time
Ramp value
(1) (1)
(2)
(5)
(6)
(3) (4)
Measured value (PV) processed
by input filter
Input amplitude
Pulse input by noiseActual measured value (PV)
Time
Time
Time
Time
Input amplitude processed
by input filter
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