HEIDENHAIN SW 54843x-03 DIN Programming - Manual (Page 390)

390 DIN Programming
4.29 Other G codes
program rear-face machining in the same way as front-face machining
(Z-axis orientation, arc rotational direction, etc.), the expert program
includes commands for converting and mirroring.
Danger of collision!
 In the transition from AUTOMATIC to MANUAL
OPERATION, conversions and mirror images are
retained
 Switch off the conversion/mirroring if you activate the
front-face machining after rear-face machining (for
example during program section repeats with M99)
 After a new program selection, the conversion/mirroring
is switched off (example: transition from MANUAL to
AUTOMATIC mode)