HEIDENHAIN MANUALPLUS 620 - Page 1071

January 2012 6.19 Configuring the Controller Unit and Drive Motors 1071
Definition of the
field angle
The following applies to the determined field angle, which is entered in
MP_motPhiRef:
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 MP_motPhiRef.
An increment is formed from <line count> · <interpolation factor>.
Therefore:
MP_motPhiRef = (<field angle at reference mark> · <line count> · 1024) /
360°
In the example below, the reference mark is at the field angle 90°, i.e.
MP_motPhiRef = (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 MP_motPhiRef = 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