Siemens SINUMERIK 840DE Programming Manual page 250

Frames
6.10 Deselect DRF (handwheel) offsets, overlaid motions and transformation (DRFOF, CORROF, TRAFOOF)
Note
CORROF is possible only from the parts program, not via synchronized actions.
Alarm 21660 is output if a synchronized action is active when the position offset is
deselected via parts program command CORROF(axis,"AA_OFF"). $AA_OFF is deselected
simultaneously and not set again. If the synchronized action becomes active later in the
block after CORROF, $AA_OFF remains set and a position offset is interpolated.
If a CORROF command has been programmed for an axis and this axis is active in a
different channel, then an axis replacement sends the axis to the other channel with machine
data 30552: AUTO_GET_TYPE = 0. This causes the DRF offset and any other position
offset to be deselected.
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Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
Fundamentals