Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 245)

4-86 Commissioning
7000-UM150I-EN-P – June 2013 7000 “B” Frame
3. Assign parameter „Speed Error‟ in the "Current Control" group
to a SCBL test point (Rect TP1 or 2). This can be done similarly
to the way that the meter assignments were described earlier in
the chapter. Then it can be displayed on your oscilloscope. Use
the settings 2V/division and 1 sec/division.
4. Adjust the reference command to a value around the middle of
the operating speed range.
5. Start the drive and wait for it to accelerate to the commanded
speed.
6. Set parameter "Speed ref step" in "Speed Control" to 0.8 Hz.
The drive speed will step up and down by this amount at regular
intervals. The step of 0.8 Hz corresponds to 4 V on the test point.
Since the speed error signal has a range of only 4 Hz in order to
achieve the required resolution for small changes in speed, the
signal may sometimes rollover (jump from +10V to -10V)
during the speed step. If this occurs, it can be eliminated by
adjusting the reference command up or down slightly.
7. Adjust the value of parameter "Total inertia " until the speed
rises to approximately 63% of its final value in 1 second as
shown in the figure. If the response time is too fast, it indicates
that “Total inertia” is set too high and should be decreased. If
the response is too slow, then “Total inertia” is set too low and
should be increased.
CORRECTLY TUNED SPEED REGULATOR
8. Set parameter "Spdreg bandwidth" to the normal operating value.
Confirm that the response time is equal to the inverse of the
speed regulator bandwidth and that there is minimal overshoot.
For example, if the speed regulator bandwidth is set to 2 rad/sec,
the speed should rise to 63% of its final value in 0.5 second.
9. Set parameter "Speed ref step" to zero and stop the drive.