32.16.5.4 Basic Function - PID
The PID instruction compares the measured values (current
values) and the set values (target values). The measured values are
based on analog input and temperature input. The instruction then
adjusts the output values to even the gap between the current
values and the target values. You can combine P control, I control,
and D control in PID control. Specify each below mentioned
parameter to be controlled.
The output value calculated by the PID control is generally
expressed by the following formula.
KP = Proportional Constant
E = Deviation (SP-PV or PV-SP)
Reset = Integral Calculus Time
Rate = Differential Calculus Time
Using the [Tuning] tab that will be described later, adjust the
sampling time to reduce the effect of noise on deviation. The
following formula shows the result of filtering on the
deviation.
EF = Result of filtering on deviation
Tloop = Frequency data
TFilter = Sampling Frequency
E = Deviation (SP-PV or PV-SP)
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