HEIDENHAIN iTNC 530 (60642x-03) - Manual (Page 447)

HEIDENHAIN iTNC 530 447
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Prerequisites for the program to be converted
The TNC reverses the sequence of all positioning blocks in the
program. The following functions are not taken into the backward
program:
 Definition of workpiece blank
 Tool calls
 Coordinate transformation cycles
 Fixed cycles and probing cycles
 Cycle calls CYCL CALL, CYCL CALL PAT, CYCL CALL POS
 Miscellaneous (M) functions
HEIDENHAIN therefore recommends converting only programs
containing a pure contour description. All path functions available on
the TNC are permitted, including FK blocks. RND and CHF blocks are
moved by the TNC so that they can be executed again at the correct
position on the contour.
The TNC also calculates the radius compensation for the other
direction.
If the program included contour approach and departure
functions (APPR/DEP/RND) check the backward program
with the programming graphics. Certain geometric
conditions might result in incorrect contours.
The program to be converted must not contain any NC
blocks with M91 or M92.