HEIDENHAIN TNC 620 (81760x-01) Cycle programming - Manual (Page 447)

MEASURE KINEMATICS (Cycle 451, DIN/ISO: G451, option) 18.4
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TNC 620 | User's Manual Cycle Programming | 3/2014
447
Backlash
Backlash is a small amount of play between the rotary or angle
encoder and the table that occurs when the traverse direction is
reversed. If the rotary axes have backlash outside of the control
loop, for example because the angle measurement is made with
the motor encoder, this can result in significant error during tilting.
With input parameter
Q432 you can activate backlash
measurement. Enter an angle that the TNC uses as traversing
angle. The cycle will then carry out two measurements per rotary
axis. If you take over the angle value 0, the TNC will not measure
any backlash.
The TNC does not perform an automatic backlash
compensation.
If the measuring circle radius is < 1 mm, the TNC
does not calculate the backlash. The larger the
measuring circle radius, the more accurately the TNC
can determine the rotary axis backlash (see "Logging
function", page 453).
Backlash measurement is not possible if an M
function for positioning the rotary axes is set in
machine parameter mStrobeRotAxPos or if the axis is
a Hirth axis.