Mechanical System - Siemens SINAMICS S120 Function Manual

Extended Functions
Function module "basic positioner"
4.24.1

Mechanical system

Features
S Backlash compensation (p2583)
S Modulo correction (p2577)
Description
Fig. 4-25
When mechanical force is transferred between a machine part and its drive, gener-
ally backlash occurs. If the mechanical system was to be adjusted/designed so
that there was absolutely no play, this would result 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 tra-
versing distance, as, at direction reversal, the axis travels either too far or not far
enough corresponding to the absolute 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
p2583 with the correct polarity. At each direction of rotation reversal, the axis
actual value is corrected dependent on the actual traversing direction and dis-
played in r2667. This value is taken into account in the position actual value using
p2516 (position offset).
If a stationary axis is referenced by setting the reference point or an adjusted axis
is powered-up with an absolute encoder, then the setting of parameter p2604
(reference point approach, starting direction) is relevant for switching-in the com-
pensation value.
4-250
Backlash:
p2583
Backlash compensation
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SINAMICS S120 Function Manual, 03/2006 Edition