Rockwell Automation 2092-DAx Ultra1500 User Manual - Manual (Page 117)

Publication 2092-UM001D-EN-P — July 2005
Ultra1500 Application Examples 5-37
Figure 5.17
Position Regulator Response During Move with Varied Kff
Kff Low Pass Filter Bandwidth
The Kff Low Pass Filter Bandwidth parameter sets the bandwidth frequency
of the low pass filter that is applied to the velocity feedforward command of
the position regulator. It can be set in the range of 0–800 Hz. The filter is
disabled when this value is set to 0. This parameter softens the velocity
command from the feedforward term for large changes in the position
command, and reduces quantization noise caused by the differentiation of the
position command. It also reduces overshoot in the position response, along
with reducing the Kff feedforward gain value.
High Error Output Offset
The High Error Output Offset parameters control a constant velocity
command offset that is added to the position regulator output when the
position error exceeds the High Error Output Threshold. The High Error
Output Offset parameter can be set in the range of 0–450 (rpm or mm/
second). This offset reduces position error.
High Error Output Threshold
The High Error Output Threshold parameter sets the position error level at
which the High Error Output Offset is applied. The High Error Output
Threshold parameter can be set in the range of 0–50,000 counts.
Kff = 0
Kff = 50
Kff = 100
Time (msec)
0 50 100
-5000
0
5000
20000
15000
Follower Positioin (counts)
10000
Kff = 100
Kff = 0