Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) Commissioning - ForGe Control - Manual (Page 104)

104 Rockwell Automation Publication 7000-IN012B-EN-P - June 2014
Chapter 4 Commissioning the Drive
Figure 78 - Speed Control Group
3. Set parameter Total Inertia in Speed Control to an initial value of 1.0 sec if
it is a low inertial application (pumps etc). Set the parameter to 5.0 seconds
if it is a high inertia application (e.g. ID Fans).
4. Assign parameter Speed Error in the Speed Control group to a test point
e.g. ITP1 on the DPM. 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.
5. Adjust the reference command to a value around the middle of the
operating speed range.
6. Start the drive and wait for it to accelerate to the commanded speed.
7. 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 0.8V or 800mV on the test point. To capture the
error set the scope at 200 mV/division and 200 msec/division. Trigger the
scope on negative edge as shown in Figure.
8. 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.