Siemens SINAMICS S120 Function Manual page 100

Servo control
3.13 Pole position identification
Pole position determination with zero marks
The pole position identification routine provides coarse synchronization. If zero marks exist,
the pole position can be automatically compared with the zero mark position once the zero
mark(s) have been passed (fine synchronization). The zero mark position must be either
mechanically or electrically (p0431) calibrated. If the encoder system permits this, then we
recommend fine synchronization (p0404.15 = 1). This is because it avoids measurement
spread and allows the determined pole position to be additionally checked.
Suitable zero marks are:
● One zero mark in the complete traversing range
● Equidistant zero marks whose relevant position to the commutation are identical
● Distance-coded zero marks
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WARNING
Before using the pole position identification routine, the control sense of the speed
control loop must be corrected (p0410.0).
For linear motors, refer to the Commissioning Manual.
For rotating motors, in sensorless operation with a small positive speed setpoint (e.g. 10
RPM), the speed actual value (r0061) and the speed setpoint (r1438) must have the
same sign.
CAUTION
If more than one 1FN3 linear motor is using saturation-based pole position identification
for commutation (p1980 <= 4 and p1982 = 1), this can reduce accuracy when the
commutation angle is determined. If a high level of accuracy is essential, (e.g. when
p404.15 = 0 or the commutation angle offset is determined with p1990 = 1), the pole
position identification runs should be carried out consecutively. This can be achieved by
staggering the time at which the individual drives are enabled.
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
Drive Functions