Power Brick Controller User Manual
Manual Motor Setup
169
DAC Offsets
Some DACs output a nonzero amount of current even when zero is commanded. This may cause
problems (e.g. a constant position offset) when you try to tune the servo loop. One can correct for this
with
Motor[].DacBias
. This amount is subtracted from the output of the servo loop every servo cycle.
The IDE software has the ability to configure this automatically in its final step of configuring a non-
commutated motor. One can also perform the calibration manually with the following procedure:
Issue a
#
n
out0
command, where
n
is the motor number.
Observe the direction of motion. If positive, decrease the value of
Motor[].DacBias
until the
motor stops moving. If negative, increase its value until the motor stops moving.
Issue
#
n
kill
to kill the motor.
Caution
Make sure the motor is unloaded and can spin freely and safely before
performing the DAC calibration.
