Siemens Sinumerik 840D sl Programming Manual page 340

Coordinate transformations (frames)
13.10 Deselecting overlaid movements (DRFOF, CORROF)
$AA_OFF in JOG mode
Also in JOG mode, 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 statement, 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 that is active in another channel has been programmed for a CORROF, it will be fetched
into the channel with an axis replacement (requirement: MD30552 $MA_AUTO_GET_TYPE
> 0) and the position offset and/or the DRF offset deselected.
340
Programming Manual, 01/2015, 6FC5398-1BP40-5BA2
Fundamentals