Fuji Electric FRENIC-Ace series, User Manual

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5.3 Description of Function Codes
5-204
J03 to J06 PID Control P (Gain), I ( Integral time), D (Differential time), Feedback filter
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P gain (J03)
J03 specifies the proportional gain for the PID processor.
• Data setting range: 0.000 to 30.000 (times)
P (Proportional) action
An operation in which the MV (manipulated value: output frequency) is proportional to the deviation is called P
action, which outputs the MV in proportion to deviation. However, P action alone cannot eliminate deviation.
Gain is data that determines the system response level against the deviation in P action. An increase in gain
speeds up response, but an excessive gain may oscillate the inverter output. A decrease in gain delays response,
but it stabilizes the inverter output.
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I integral time (J04)
J04 specifies the integral time for the PID processor.
• Data setting range: 0.0 to 3600.0 (s)
0.0 indicates that the integral component is ineffective
I (Integral) action
An operation in which the change rate of the MV (manipulated value: output frequency) is proportional to the
integral value of deviation is called I action, which outputs the MV that integrates the deviation. Therefore, I action
is effective in bringing the feedback value close to the commanded value. For the system whose deviation rapidly
changes, however, this action cannot make it respond quickly.
The effectiveness of I action is expressed by integral time as parameter, that is J04 data. The longer the integral
time, the slower the response. The reaction to the external disturbance also becomes slow. The shorter the integral
time, the faster the response. Setting too short integral time, however, makes the inverter output tend to oscillate
against the external disturbance.
Deviation
Time
Time
Manipulated
value
Deviation
Time
Time
Manipulated
value