5
5.5 SIMODRIVE POSMO A functions
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SIMODRIVE POSMO A User Manual (POS1) – 08/2013 Edition
5.5.5 Backlash compensation and correction direction (from SW 1.4)
When an indirect measuring system is used (position measuring en-
coder 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.
Backlash
Table
For a direction reversal, the encoder actual value leads the
actual value (table) ––> the table does not traverse far enough
M Motor
G Encoder
M
G
Fig. 5-13 Backlash
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.
Description
Example:
Determining the
backlash
5 Description of the Functions
02.9904.01