5.3 Description of Function Codes 5.3.8 J codes (Applied functions)
PID Control P (Gain), I (Integral time), D (Differential time), Feedback filter
Related function codes: J59: P (Gain) 2
J60: I (Integral time) 2
J61: D (Differential time) 2
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.
It may be necessary to adjust the P gain when performing dancer control based on differences in machine inertia
associated with thick winding and thin winding, or if there is a large deviation from the reference position when the
dancer starts.
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.
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