6
6.2
Positioning mode (P0700 = 3, from SW 2.1)
6-376
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SIMODRIVE 611 universal Description of Functions (FBU) – 04.05 Edition
When mechanical force is transferred between a machine part and its
drive, generally backlash occurs. If the mechanical system was to be
adjusted/designed so that there was absolutely no play, this would re-
sult in high wear. Thus, backlash (play) can occur between the machine
component and the encoder.
For axes with indirect position sensing, mechanical backlash results in
a falsification of the traversing distance, as, at direction reversal, the
axis travels either too far or not far enough corresponding to the abso-
lute value of the backlash.
Note
The backlash compensation is active, after
the axis has been referenced for incremental measuring systems
the axis has been adjusted for absolute measuring systems
In order to compensate the backlash, the determined backlash must be
specified in P0201 with the correct polarity.
At each direction of rotation reversal, the axis actual value is corrected
dependent on the actual traversing direction.
Backlash
Table
ÏÏ
ÏÏ
ÏÏÏÏÏ
ÏÏÏÏÏ
The encoder actual value leads the actual
value (table) at direction reversal.
––> the table doesn’t travel far enough
––> positive backlash (standard case)
Backlash
ËËËËËËËËË
ËËËËËËËËË
The actual value (table) leads the encoder
actual value at a direction of rotation reversal.
––> the table travels too far
––> negative backlash
M
ÏÏÏ
ÏÏÏ
ÏÏÏ
ÏÏÏ
Table
Rack
M: Motor
G: Encoders
M
G
G
Fig. 6-14 Positive and negative backlash compensation
Backlash
compensation
P0201
6 Description of the Functions
01.99
! not 611ue !