Definition Of The Field Angle - HEIDENHAIN iTNC 530 HSCI Technical Manual

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7.9.6 Definition of the field angle

Reference mark

The following applies to the determined field angle, which is entered in

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

star point) and U

(phase 2 to star point) are measured. The positive peak

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>.

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.

:Motor voltage between phase 1 and star point

:Motor voltage between phase 2 and star point

FA: Field angle in degrees

:Field angle in increments for an encoder with 2048 lines and 1024-

fold interpolation (2048 · 1024 = 2 097 152)

7.9 Field orientation