Mechanical System - Siemens SINAMICS S120 Function Manual

8.8.1

Mechanical system

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 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 traversing distance, as, at direction
reversal, the axis travels either too far or not far enough corresponding to the absolute value
of the backlash.
Figure 8-13
Note
The backlash compensation is active with the following settings:
• 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 actual axis value is
corrected dependent on the actual traversing direction and displayed in r2667. This value is
taken into account in the actual position 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 compensation value.
Table 8- 7
p2604
0
1
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
Backlash compensation
The compensation value is switched in as a function of p2604
Traversing direction
Positive
Negative
Positive
Negative
Switch in compensation value
None
Immediately
Immediately
None
Function modules
8.8 Basic positioner
509