Advanced commissioning
7.6 Basic positioner and position control
Converter with control units CU250D-2
170
Operating Instructions, 04/2015, FW V4.7.3, A5E34261542B AB
7.6.3.4
Setting the backlash
Description
Backlash (also called play, dead travel on reversing etc.) is the
distance or the angle that a motor must travel through when the
direction of rotation reverses until the axis actually moves in the
other direction.
Backlash in a spindle
With the appropriate setting, the inverter corrects the positioning error caused by the
backlash when reversing.
The inverter corrects the backlash under the following condition:
●
For an incremental encoder, the axis must be referenced.
See also section: Referencing (Page 185).
●
For an absolute encoder, the axis must be adjusted.
See also section: Absolute encoder adjustment (Page 200).
Measuring backlash
Procedure
To measure the backlash, proceed as follows:
1.
Move the axis to position A in the machine. Mark this position in the machine and note
down the actual position value in the inverter, see also Section: Checking the actual
position value (Page 169).
2.
Move the axis a little bit more in the same direction.
3.
Move the axis in the opposite direction until the actual position value in the inverter shows
the same value as at position A. Due to the backlash when reversing, the axis is now at
position B.
4.
Measure the position difference
Δ
= A - B in the machine.
Figure 7-27 Measuring backlash
You have measured the backlash.
