6-19
Note 1. The maximum frequency (FMAX) is reached with 10-V input.
Note 2. The maximum frequency (FMAX) is reached with 20-mA input. The SW2 on the control PCB
must be switches from V to I.
Note 3. Set n149 for the pulse train input scale to the pulse train frequency that is equivalent to the
maximum frequency (FMAX).
Note 4. Make sure that the target value input and feedback value input do not overlap with each other.
6-3-7 PID Adjustments
H PID Adjustments with Step Response Method
• The following describes how to adjust each parameter of PID control by monitoring the step response
of the target of control.
1. Measurement of Step Response Waveform
Take the following steps to measure the step response waveform of the target of control.
a) Connect the load in the same way as the connection of the load to the Inverter in normal opera-
tion.
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.
Note Measure the response waveform so that the timing of the step input will be known.
2. Calculation of PID Parameters
S Draw a tangent line that comes into contact with the steepest inclination point of the 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 intersection of the tan-
gent line and time axis.
Advanced Operation Chapter 6
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