Siemens SINUMERIK 840D sl Function Manual page 314

Manual and Handwheel Travel (H1)
Handwheel override in automatic mode
Dry-run feedrate
With active dry run
DB21, ... DBX0.6 (activate dry-run feedrate) = 1,
the dry-run feedrate is always effective
SD42100 $SC_DRY_RUN_FEED.
In this way, the axis is traversed to the programmed target position at dry-run feedrate
without any influence from the handwheel despite the active handwheel override with path
default (FDA[AXi] = 0), i.e. the path default is ineffective.
DRF active
When "Handwheel override in automatic mode" is activated, it is important to check whether
the "DRF" function is active (DB21, ... DBX0.3 = 1).
If this were the case, the handwheel pulses would also cause a DRF offset of the axis.
The user must, therefore, first deactivate DRF.
Feedrate override
The feedrate override does not affect the velocity of the movements produced by the
handwheel (exception: 0%). It only affects the programmed feedrate.
With path default and fast handwheel movements, the axis may not be able to follow the
handwheel rotation synchronously (especially in the case of a large handwheel-pulse
weighting), causing the axis to overtravel.
314
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Extended Functions