Siemens SINAMICS S120 Function Manual page 97

Determining the pole position with zero marks
Pole position identification provides a means of performing coarse synchronization.
If zero marks have been defined, the pole position can be compared automatically
with the zero mark position once the zero mark(s) has/have been passed (fine syn-
chronization). The zero mark position must be compared mechanically or electri-
cally (p0431). If permitted by the encoder system, fine synchronization is recom-
mended (p0404.15 = 1) because it avoids measurement variations and enables the
pole position determined to be checked.
Suitable zero marks:
S One zero mark across the entire traversing range
S Equidistant zero marks, whose relative positions are identical with respect to
the commutation
S Distance-coded zero marks
Determining a suitable method of pole position identification
* A saturation-based method can be
used.
Fig. 3-18
© Siemens AG, 2005. All rights reserved
SINAMICS S120 Function Manual, 06/05 Edition
Can the motor rotate freely
(No external forces)?
Is the motor ironless?
Selection of method
* Set method 1980 =
10
Yes
* Enable pulses and start pole
position identification
* Pole position identification is not
possible
Yes
* A mechanically adjusted encoder
with absolute information must be
used .
Operating Modes
Servo control
3-97