Rockwell Automation 8510 AC Spindle Drive System Programming Manual - Manual (Page 43)

Drive Tuning
Chapter 3
3-40
Spindle orient tuning should be adjusted with the maximum expected load
inertia connected to the system, if possible. If this is not possible, estimate
the maximum expected load inertia versus the current value of load inertia.
Reduce the maximum allowed peak torque during the spindle orient tuning
by this ratio. For example, if the worst case load inertia would be about
twice the system inertia during setup, adjust the Orient Speed and Orient
Start parameters to require no more than one half the drive peak torque
capability during setup.
Orient Tuning Procedure
o 1. Verify proper orient operation using the default values for Orient
Speed and Orient Start.
o 2. Program ANALOG OUTPUT – Output #1 for “
±
MOTOR RPM” and
ANALOG OUTPUT – Output #2 for “% TORQUE.” Use an
oscilloscope to monitor the % Torque during orient.
If the system can be tested with the maximum expected load inertia
connected, the peak torque during decel should not exceed 95% of
maximum capability (9.5 volts on Analog Output #2). If the system is
being setup without a workpiece or tooling installed, the
recommended maximum torque value is 40% of peak torque
capability (4 volts output) for a lathe and 70% of peak torque
capability (7 volts output) for a machining center. For systems with a
completely known and repeatable load inertia and torque requirement,
a small amount of torque limiting is acceptable and will usually
shorten the time to decelerate to the target position.
o 3. Observe the peak torque required when using the default values of
Orient Speed and Orient Start. Compare this observed peak torque
with the desired peak torque defined above to determine the necessary
adjustments to the Orient Speed and Orient Start settings. For
example, if the observed peak torque was 25% of the target value,
then potential actions are to:
- Increase Orient Speed setting from 60 to 240 rpm and Orient Start
from 45 to 180 degrees (maintain Kp at 8 radians/second while
raising Orient Speed a factor of 4), or
- Reduce Orient Start from 45 degrees to 11.25 degrees without
changing Orient Speed setting (quadruple Kp from 8 to 32 radians/
second with the same Orient Speed), or
- Increase Orient Speed setting from 60 to 120 rpm without changing
Orient Start setting (double Kp to 16 radians/second and double the
Orient Speed).
o 4. Adjust Orient Speed and Orient Start to give desired levels of peak
torque during orient. Assure that the spindle does not overshoot target
position by viewing actual spindle motion and observing
±
MOTOR
RPM and % TORQUE analog outputs with the oscilloscope. If
position overshoot occurs, increase value of Orient Start to reduce
Kp.