Rockwell Automation 1771-QB Linear Pos. - Manual (Page 99)

Formatting Module Data (WRITES)
Chapter 7
7Ć20
Figure 7.26
Gain Break Plot
Commanded Axis
speed
Following
Error
50069
Immediate Stop
Desired
Gain
Maximum Velocity
Gain Break speed
Proportional
Gain
Gain
Factor
= x
slope (IPS/mil) = Proportional Gain
Gain Break
Point
Max Following Error
Excess Error
(Determined by Excess
Following Error Parameter)
Typically, at axis speeds below the gain break velocity, you would use a
relatively high gain to allow precise axis positioning. By reducing the gain at
axis speeds above the gain break speed, we can achieve better stability in some
applications.
The gain break speed must not exceed the maximum velocities specified in the
analog calibration constants.
If you don’t want a gain break speed, set the gain break speed and gain factor
parameters to zero. (If you set a non-zero gain factor and a zero gain break
speed, the reduced or increased gain applies to all axis speeds.)
Gain Factor (words 19 and 48)
The gain factor parameter determines how much the proportional gain is
reduced or increased at speeds above the gain break speed. It is expressed as a
ratio of the new desired gain over the proportional gain.