Fuji Electric FRENIC-HVAC User Manual page 506

Follow the procedure below to set data to PID control function codes.
It is highly recommended that you adjust the PID control value while monitoring the system
response waveform with an oscilloscope or equivalent. Repeat the following procedure to
determine the optimal solution for each system.
- Increase the data of function code J110/J210 (PID control P (Gain)) within the range where
the feedback signal does not oscillate.
- Decrease the data of function code J111/J211 (PID control I (Integral time)) within the
range where the feedback signal does not oscillate.
- Increase the data of J112/J212 (PID control D (Differential time)) within the range where
the feedback signal does not oscillate.
Refining the system response waveforms is shown below.
1) Suppressing overshoot
Increase the data of function code J111/J211 (Integral time) and decrease that of
J112/J212 (Differential time).
2) Quick stabilizing (moderate overshoot allowable)
Decrease the data of J110/J210 (Gain) and increase that of J112/J212 (Differential time).
3) Suppressing oscillation whose period is longer than the integral time specified by function
code J111/J211
Increase the data of J111/J211 (Integral time).
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