User Manual 08/2003 Edition

02.99 04.01
Siemens AG 2003 All rights reserved
SIMODRIVE POSMO A User Manual (POS1) – 08.03 Edition
5.5 SIMODRIVE POSMO A functions
5.5.5 Backlash compensation and correction direction (from SW 1.4)
Description
Example:
Determining the
backlash
When an indirect measuring system is used (position measuring encoder
at the motor), at each direction reversal, the mechanical play is first
traveled through before the axis moves.
For this measuring system, mechanical play falsifies the traversing
distance. This is because at direction reversal, the axis moves too little
by the absolute value of the play.
After entering the backlash compensation and the correction direction,
at each direction reversal, the axis actual value is corrected depending
on the actual traversing direction.
M
G
Table
Backlash
ÏÏÏ
ÏÏÏ ÏÏÏÏÏ
ÏÏÏÏÏ
M Motor
G Encoder
For a direction reversal, the encoder actual value leads the
actual value (table) ––> the table does not traverse far enough
Fig. 5-11 Backlash
5 Description of the Functions
The following procedure is recommended to determine the backlash of
an axis:
Traverse the axis e.g. in the positive direction – take up the play
Mount a dial gauge on the axis mechanical system
Note down the actual position 1 (read P40)
Traverse the axis in the negative direction until axis movement can
be detected at the dial gauge
Note down the actual position 2 (read P40)
The backlash is obtained from the difference between actual position 1
and actual position 2.
5-161
5