Bosch Rexroth IndraDrive MPH-02 Functional Description page 243

MPH-02, MPB-02, MPD-02
Application-Related Aspect
Method
Synchronous Motors with
Absolute Measuring System
Sequence of the Sine-Wave
Method for Synchronous Motors
with Absolute Measuring System
DOK-INDRV*-MP*-02VRS**-FK01-EN-P
Determining the Commutation Offset, Sine-Wave Method
The sine-wave method for determining the commutation offset can be
used for all types of synchronous motors. It should only be used if the
saturation method cannot be used for determining the commutation
offset.
The disadvantage of the sine-wave method is that the motor has to be put
into motion by supplying current. Limitations of the motivity, e.g. friction or
blocking, can reduce the quality of offset determination or even cause
offset determination to fail!
Note: Observe the restrictions for the sine-wave method (see table
above "Restrictions for sine-wave method")!
By a sinusoidal test signal the voltage and frequency of which requires
motor-specific settings (P-0-0506, Amplitude for angle acquisition,
P-0-0507, Test frequency for angle acquisition), the controller
determines the commutation offset of the synchronous motor. It is
therefor necessary that the generated test current puts the motor into
motion.
Note: The maximum motion range for the sine-wave method is +/-
45° /PPN for rotary motors and ½ pole pair distance for
(mech)
linear motors!
The motor-specific setting of voltage and frequency of the test current is
carried out automatically when the value "0" has been entered in
parameter P-0-0506 at the start of P-0-0524, C1200 Commutation offset
setting command. The detected motor-specific values for P-0-0506 and
P-0-0507 are stored and used for commutation setting for further
operations.
Carrying Out the Sine-Wave Method (Commissioning)
In the case of synchronous kit motors with absolute measuring system,
the sine-wave method is only started by a command at the initial
commissioning and the determined commutation offset value is stored in
the controller or in the encoder data memory. In addition, the value can be
manually optimized during the initial commissioning.
1. In P-0-0522, Commutation setting control word activate:
• initial commissioning mode and
• sine-wave method
2. Make presettings for automatic determination of motor-specific
parameter values (P-0-0506, P-0-0507) of the test signal required for
determining the commutation offset:
• enter value "0" in P-0-0506, Amplitude for angle acquisition
3. Switch drive to operating mode ("AB"); start sine-wave method by
P-0-0524, C1200 Commutation offset setting command
4. After the current was supplied and the commutation offset value has
been successfully determined, this value, due to the initial
commissioning mode, is simultaneously stored in the following
parameters in the case of absolute measuring systems:
• P-0-0508, Commutation offset
• P-0-0521, Effective commutation offset,
• P-0-3008, Commutation offset, encoder memory (if available)
6-31
Drive Control