HEIDENHAIN iTNC 530 HSCI - Definition of the Field Angle

July 2013 7.9 Field orientation 1121
7.9.6 Definition of the field angle
The following applies to the determined field angle, which is entered in
MP2556.x:
The field angle is determined for 360° electrical rotation of the motor, not for
mechanical rotation.
The motor is moved with external power in the positive direction (when
viewing the shaft, the shaft rotates clockwise). The voltages U
1-Y
(phase 1 to
star point) and U
2-Y
(phase 2 to star point) are measured. The positive peak
value of U
1-Y
corresponds to a field angle of 90°.
The field angle at the reference mark is saved in increments in MP2256.x An
increment is formed from <line count> · <interpolation factor>.
Therefore:
MP2256.x = (<field angle at reference mark> · <line count> · 1024) / 360°
In the example below, the reference mark is at the field angle 90°,
i.e. MP2256.x = (90° · 2048 · 1024) / 360° = 524288.
On a "standard" synchronous motor (with aligned speed encoder), the
reference mark is at the field angle 0°. If the field angle were to be determined
for this motor, the result would be MP2256.x = approx. 2097152.
 U
1-Y
:Motor voltage between phase 1 and star point
 U
2-Y
:Motor voltage between phase 2 and star point
 FA: Field angle in degrees
 FA
2048
:Field angle in increments for an encoder with 2048 lines and 1024-
fold interpolation (2048 · 1024 = 2 097 152)
90
180
120
270 360
U
1-Y
U
2-Y
Reference mark
524 288 1 048 576 1 572 864 2 097 152
FA
2048
FA