ACU-RITE MILLPWR G2, Technical Manual

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340 ACU-RITE Technical Manual MILLPWR
G2
Feedback control
with following error Following error (also known as servo lag) is a gap that remains between the
nominal position commanded by the NC and the actual position of the axis.
Simplified representation:
The nominal position value snoml for a given axis is compared with the actual
position value sactl and the resulting difference is the following error sa:
sa = snoml – sactl
sa = following error
snoml = nominal position value
sactl = actual position value
The following error is multiplied by the kv factor and passed on as nominal
velocity value:
v = kv · sa
vnoml = nominal velocity value
The control loop gain, known as the kv factor, defines the amplification of the
position control loop. You must find the optimum kv factor by trial and error.
If you choose a kv factor that is too large, the following error will become very
small. However, this can lead to oscillations.
If you choose too small a kv factor, the axis will move to a new position too
slowly.
For axes that are interpolated with each other, the kv factors must be equal to
prevent contour deviations.
 Define the kv factor in MP_kvFactor.