BacklashDistance Parameter
Default Value: 0.0
Minimum Value: None
Maximum Value: None
Units: distance
Type: double
WARNING: Do not set the BacklashDistance parameter to a value that is too large. Backlash compensation can cause a step change to occur in the position command of an axis. A parameter value that is too large can cause the controller to generate unexpected motion, a position error, or over-current faults.
The BacklashDistance parameter compensates for backlash error in the mechanical drive system of an axis. Backlash error can cause the position of an axis to be incorrect as a result of direction reversals. It occurs in drive systems such as ball screws, lead screws, and belt drives. The value specified in this parameter is added to or subtracted from the position command of the axis each time the direction of commanded motion changes.
The backlash compensation contribution to the position command is zero at the end of the home cycle:
- If the final move of the home cycle is in the negative direction, a positive move causes a backlash contribution of +(BacklashDistance), and a negative move causes a backlash contribution of 0.
- If the final move of the home cycle is in the positive direction, a positive move causes a backlash contribution of 0, and a negative move causes a backlash contribution of -(BacklashDistance).
You must home the axis in order for backlash compensation to be active. Use Machine Setup to configure backlash compensation on an axis.
To prevent unwanted direction reversals in the commanded motion, set the MotionUpdateRate Parameter to a minimum value of 1 kHz.
If you set the BacklashDistance parameter to a large value, it can cause sudden changes in the position command. To make these changes smooth, use the BacklashIirFilter Parameter.
The ReverseMotionDirection Parameter has no effect on this parameter.
