Power Brick Controller User Manual
Manual Motor Setup
147
Hall Effect Phasing
Digital Hall Effect sensors can be used for computing a rough absolute phase reference on power-up without
the need for a phasing search move. They provide absolute information about where the motor is positioned
with respect to its commutation cycle. They are desirable because, just like with absolute encoders, the
motor can be phased on power-up without any movement.
Note
Inherently, digital hall sensors have an error of about ±30°, resulting
in a loss of torque of about 15%. This should be corrected (fine
phasing) for top operation.
The Power Brick AC supports both the conventional 120°, and less common 60° spacing. This section
focuses on the more standard 120° spacing, each signal nominally with 50% duty cycle, and nominally 1/3
cycle apart.
Channel
U
Channel
V
Channel W
-60° 0° 60° 120° 180° -120° -60° 0° 60°
Setting up digital Hall Effect sensors’ absolute phasing requires:
The motor to be phased initially (using the stepper/manual technique)
Moving the motor either by hand or with jog commands.
Moving the motor by hand with geared or loaded motors may not be possible. In these cases, it is
recommended to perform the open loop test and rough position loop tuning first then come back
for setting up the Hall sensors.
The key motor structure elements necessary for configuring Hall sensors’ absolute phasing are:
Motor[].pAbsPhasePos =
PowerBrick[].Chan[].Status.a
Motor[].AbsPhasePosFormat =
$400030C (always for halls 120° spacing)
Motor[].AbsPhasePosSf
The
Motor[].AbsPhasePosSf
reflects the direction sense of the halls with respect to the
commutation counting direction. This is the UVW transition when moving the motor in the positive
direction of the encoder:
= 2048 / 12 if the
PowerBrick[].Chan[].UVW
transition is from 1 to 3
= -2048 / 12 if the
PowerBrick[].Chan[].UVW
transition is from 3 to 1
Motor[].AbsPhasePosOffset
The
Motor[].AbsPhasePosOffset
is the phase position at that transition.
