6-22
6-3-7 PID Adjustments
H PID Adjustments with Step Response Method
·ThefollowingdescribeshowtoadjusteachparameterofPIDcontrolbymonitoringthe
step response of the target of control.
1. Measurement of Step Response Waveform
Takethefollowingstepstomeasurethestepresponsewaveformofthetargetofcon-
trol.
a) Connect the load in the same way as the connection of the load to the Inverter in
normal operation.
b) Set n128 to 0 so that the Inverter will not perform PID control.
c) Minimize the acceleration time and input the step frequency reference.
d) Measure the response waveform of the feedback.
NoteMeasure the response waveform so that the timing of the step input will be
known.
2. Calculation of PID Parameters
S Drawatangentlinethatcomesintocontactwiththesteepestinclinationpointofthe
response waveform.
S Measurement of R
Measure the gradient of the tangent line provided that the set point is 1.
S Measurement of L
Measure the required time (seconds) between the origin and the point of intersec-
tion of the tangent line and time axis.
S Measurement of T
Measure the required time (seconds) between the point of intersection of the tan-
Advanced Operation Chapter 6
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