Filter Adjustments - Parker Gemini GV Series Installation Manual

7.
If ringing or oscillations persist, and do not seem to be affected by the above
adjustments, you may need to use notch filters or lead/lag filters. See the Filter
Adjustments procedure below.

Filter Adjustments

If the previous tuning procedures did not eliminate ringing or oscillations, then
mechanical resonances may be causing problems with your system's response.
Before trying the procedure below, we recommend that you check your mechani-
cal system, especially the mechanical stiffness and mounting rigidity of your
system. Use bellows or disk style couplers, not helical couplers. Once you have
optimized your mechanical system, filters may allow increased performance,
without causing system instability.
Filters can improve response by reducing system gain over the same frequencies
that contain resonances. You can then increase the gain for frequencies outside this
range, without exciting the resonance and causing instability.
The first procedure below describes how to set the drive's two notch filters, to
reduce resonance and improve your system's response. The second and third
procedures describe how to set the drive's lead and lag filters.
These procedures cause the motor shaft to move. Make sure that shaft motion will
Notch Filter Adjustment Procedure
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. Using the DNOTAD command, slowly increase the depth of the notch filter from 0.0
11. Compare the response to a step input to the response you observed in Step 8 .
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After you achieve a satisfactory system response, reconfigure the drive for position
mode (DMODE6, DMODE7, or DMODE8). This completes the advanced tuning
procedure.
WARNING
not damage equipment or injure personnel.
Configure the analog monitor to show q-axis current (DMONAV19).
Configure the drive for torque mode (DMODE2).
Configure DMTLIM to approximately 1/3 of the default value for your Compumotor
motor.
Connect one channel of your oscilloscope to the drive's ANALOG MONITOR A (pin
21). Connect your oscilloscope's ground to the drive's ANALOG GROUND (pin 25).
Connect a sine wave generator, with the amplitude set to minimum, to the drive's
torque command input, pin 23. (Connect the signal generator's ground to the drive's
CMD-, pin 24, and also to the drive's analog ground, pin 25.)
You may need to adjust the DC offset of the generator periodically to keep the load
within its travel limit.
Slowly sweep the sine wave frequency, observing the oscilloscope or the load. Start
at low amplitude, increasing gradually to a level that gives an observable response.
Find the frequency that gives the maximum response. (If no oscilloscope is
available, you may be able to find this frequency by sound or by touch).
Note the frequency that causes the maximum response.
Configure the drive for the appropriate tuning mode (torque, velocity, or position).
Observe the system's response to the tuning mode's step input.
Set the notch filter to the frequency noted in Step 7 (DNOTAF command).
to 1.0 until the ringing decreases.
Ringing should be reduced or eliminated.
Chapter 3 – Configuration
33