User Manual

Sinusoidal Commutation
Advanced Digital Motor Controller User Manual 113
Important Notice
All angles values entered or displayed by the controller are in 0-511 value where 0 =
0 degrees or radians, and 511 is 360o or 2r radians.
Zero Reference Search for Incremental Encoders
Incremental Encoders do not output an absolute position value. The Zero Reference
search is therefore performed every time the controller is powered on. See also “Incre-
mental Encoder-Only” on page 103
Hall Sensors Position Mapping
Hall sensors are often not precisely located at the 0, 60, 120, 180, ... positions. While
some imprecision has little effect in trapezoidal mode, misalignment of even a few de-
grees will have disruptive effect when operating in sinusoidal mode. When used with Hall
sensors, the automatic setup procedure captures and maps the angle at which each of the
six hall transitions occurs within an electrical turn, regardless of their wiring order.
Linearity Correction Map
Sensor are not alway totally linear. This causes the sensed angle to be measured with
periodic errors along the sensor travel. During the automatic setup process, the controller
maps the values read from the sensor for every mechanical degree over a full turn. It then
build a correction table which is applied in real-time as the motor spins.
360
0
0
360
Linear
Non-Linear
Actual Mechanical Position
Reported Position by Sensor
FIGURE 8-12. Sensor non-linearity correction
Windings and Sensor Order.
The wiring order of the U, V, W motor cable, the A, B, C Hall Sensors inputs, the A, B
Encoder inputs and/or the Sin, Cos signals are all related to each other. Swapping any of
the motor wires will make the motor turn in the opposite direction. Swapping any sensor
cables affects the angle and counting direction.
The Automatic Setup will detect the wiring order of the motor and sensors, and set the
corresponding bits in the SWD configuration register in order to virtually swap the connec-
tions so that all are moving/sensing in the same direction.