Aerotech UNIDEX 600 Series, User Manual

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U600 User’s Guide AerTune
Version 1.4
Aerotech, Inc.
5-19
5.5.5. AffGain - Acceleration Feedforward Gain
This is the Acceleration Feedforward Gain. It is the only parameter in the acceleration
feedforward loop in the UNIDEX 600’s servo loop. This parameter is used to remove
position error during the acceleration and deceleration phase of a move. Normally this
parameter has a magnitude of less than 200. The user may not have to set this servo loop
parameter greater than zero.
5.5.6. Alpha - AffGain Filter
The Alpha parameter is used within the acceleration feedforward portion of the servo
loop. It is responsible for filtering the effect of the AffGain parameter reducing the noise
introduced into the servo loop by the rapid velocity changes the AffGain produces. The
Alpha parameter has inverse scaling, 65,536 produces minimum filtering and 1, maximum
filtering
5.5.7. VGain - Constant Velocity Gain
This parameter is used primarily for tachometer based (velocity loop) systems to reduce
the position error (following error) during constant velocity. It can also be used in torque
mode systems with large frictional loads. The VGain parameter is multiplied by the
commanded velocity to produce a voltage proportional to velocity that is added to the
DAC output value to the servo amplifier that minimizes the following error.