Siemens SINUMERIK 840D sl Programming Manual page 376

Coordinate transformations (frames)
12.10 Deselecting overlaid movements (DRFOF, CORROF)
Example 5: Axial deselection of a DRF offset and a $AA_OFF position offset (2)
A DRF offset is generated in the X and Y axes by DRF handwheel traversal. No DRF offsets
are operative for any other axes in the channel.
Program code
N10 WHEN TRUE DO $AA_OFF[X]=10 G4 F5
...
N70 CORROF(Y,"DRF",X,"AA_OFF")
...
Further information
$AA_OFF_VAL
Once the position offset has been deselected by means of $AA_OFF, system variable
$AA_OFF_VAL (integrated distance of axis override) for the corresponding axis will equal
zero.
$AA_OFF in JOG mode
In JOG mode too, if $AA_OFF changes, the position offset will be interpolated as an overlaid
movement if this function has been enabled via machine data MD 36750
$MA_AA_OFF_MODE.
$AA_OFF in synchronized action
If a synchronized action which immediately resets $AA_OFF
(DO $AA_OFF[<axis>]=<value>) is active when the position offset is deselected using the
CORROF(<axis>,"AA_OFF") part program command, then $AA_OFF will be deselected
and not reset, and alarm 21660 will be signaled. However, if the synchronized action
becomes active later, e.g. in the block after CORROF, $AA_OFF will remain set and a position
offset will be interpolated.
Automatic channel axis exchange
If an axis for which CORROF has been programmed is active in another channel, it will be
pulled into the channel when the axis changes (condition: MD30552 $MA_AUTO_GET_TYPE
> 0) and then the position offset and/or the DRF offset will be deselected.
376
Comment
; A position offset == 10 is
interpolated for the X axis.
; The DRF offset of the Y axis and the
position offset of the X axis are
deselected; the DRF offset of the X
axis is retained.
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
Fundamentals