Pole Position Identification - Siemens SINAMICS S120 Function Manual

3.1.11

Pole position identification

Description
The pole position identification function determines the electrical pole position of
synchronous motors, which is required for field-oriented closed-loop control. The
electrical pole position is normally provided by a mechanically-adjusted encoder
with absolute information. In this case, pole position identification is not necessary.
Pole position identification is not necessary with the following encoder properties:
S Absolute value encoder (e.g. EnDat)
S Encoder with C/D track and number of pole pairs ≤ 8
S Hall sensor
S Resolver with integral ratio of number of motor pole pairs to number of encoder
pole pairs
S Incremental encoder with integral ratio of number of motor pole pairs to encoder
pulse number
Pole position identification is used for:
S Determining the pole position (p1982 = 1)
S Supports commissioning when determining the commutation angle offset
(p1990 = 1)
S Carrying out plausibility checks for encoders with absolute information
(p1982 = 2)
Warning
!
With non-braked motors, the measurement can cause the motor to rotate or move
via the specified current.
The degree of movement depends on the specified current intensity and the
moment of inertia of the motor and load.
© Siemens AG, 2005. All rights reserved
SINAMICS S120 Function Manual, 06/05 Edition
Operating Modes
Servo control
3-95