Download DEVA004 User's Manual V3.5 - Deva Electronic Controls Ltd

Configuration files
DEVA004 User’s Manual
A value of 0.0 may be used to disable this feature.
4.3.29 AFF
If a non-zero VP enables the speed loop, the AFF parameter is used to set the
Acceleration Feed Forward term in the speed loop. The parameter defines a
contribution to the output that is generated from demanded acceleration without
reference to the feedback system (open loop). Increasing this parameter from 0.0 has
the effect of reducing the speed error or lag of the system during the acceleration
phases of a motion. However, as AFF is increased, greater reliance is placed on the
accuracy and stability of servo amplifier parameters such as the voltage/torque
constant. Allowed values of AFF are from 0.0 to a maximum value 1.0 with typical
values in the range 0.25 to 0.75.
A value of 0.0 may be used to disable this feature.
4.3.30 ACTIVATE_CONTROL_DEADBAND,
MAINTAIN_CONTROL_DEADBAND and
CONTROL_DEADBAND_FLAGS
The purpose of the control deadband is to disable axis control when the axis arrives
within the band specified by the ACTIVATE_CONTROL_DEADBAND. Control
remains
disabled
unless
the
axis
moves
outside
of
the
MAINTAIN_CONTROL_DEADBAND or a move is started.
The MAINTAIN_CONTROL_DEADBAND can optionally be left undefined, set to a
larger value than ACTIVATE_CONTROL_DEADBAND to provide some hysteresis or
set to zero.
The concept is that ACTIVATE_CONTROL_DEADBAND is set to the position band
that the machine can achieve and that MAINTAIN_CONTROL_DEADBAND may
optionally be set to the position band that the application requires. For example, the
machine may reliably achieve target position to within 2um but hunt within this region.
So, ACTIVATE_CONTROL_DEADBAND would be set to 0.002. However, due to the
requirements of the application it may be only necessary that the axis remains
stationary
within
a
10um
band
around
target.
The
MAINTAIN_CONTROL_DEADBAND would then be set to 0.010. If the axis drifted or
was moved outside this band, the control would reactivate until the axis returned to
within ACTIVATE_CONTROL_DEADBAND.
Optionally, the CONTROL_DEADBAND_FLAGS parameter may be used to change
operation of the control deadband. To use this parameter, a bit-pattern is constructed
where a logical ‘1’ in a particular position enables a particular feature.
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