Tuning Descriptions; Current Regulator Settings; Gain; Low Pass Filter Bandwidth - Allen-Bradley Ultra1500 2092-DA1 User Manual

Tuning Descriptions

This section provides explanations of the Ultra1500 tuning parameters
available for adjustment.

Current Regulator Settings

Although the current regulator of the Ultra1500 is automatically tuned using
the electrical parameters of the motor, there are three settings available to the
user:
•

Gain

•

Low Pass Filter Bandwidth

•

Resonant Frequency Suppression

Gain
The Gain parameter lowers the current loop bandwidth from its optimum
setting, and can be set to Low, Medium, or High. The default value of High
results in a bandwidth of approximately 2 kHz. The Medium setting results in
a 33% reduction from the High setting. The Low setting results in a 67%
reduction from the high setting. This parameter can de-tune the current
regulator to reduce audible noise at the expense of performance. Some linear
motor systems have particularly high levels of acoustic noise, and the
application may require quieter operation. The velocity and position loops
should be re-tuned after changing this parameter.
Low Pass Filter Bandwidth
The Low Pass Filter Bandwidth parameter sets the cutoff frequency of the
pass filter that is applied to the current command input for the current
regulator. It can be set in the range 0–10,000 Hz. The filter is disabled when
this value is set to 0. This filter reduces noise generated by low encoder
resolutions or mechanical resonance in the system. This filter setting also limits
the current loop bandwidth. The velocity and position loops should be
re-tuned after changing this parameter.
Resonant Frequency Suppression
The Resonant Frequency Suppression parameter sets the center frequency of a
stop-band (notch) filter that is applied to the current command input for the
current regulator. It can be set in the range 0–10,000 Hz. This filter attenuates
a narrow band of frequencies centered at the parameter setting. It is useful to
reduce the effects of a mechanical resonance.
The Ultraware screen capture in Figure 5.9 shows the velocity feedback and
current command for a load with a mechanical resonance at approximately 458
Hz. The motor is rotating at approximately 200 rpm with a light torque load.
Ultra1500 Application Examples
Publication 2092-UM001D-EN-P — July 2005
5-27