HEIDENHAIN TNC 426 (280 476) - Manual (Page 213)

186 7 Programming: Miscellaneous functions
7.
4 Miscellaneous F
unctions f
o
r Cont
our
ing Beha
vior
Input
If you enter M120 in a positioning block, the TNC continues the dialog
for this block by asking you the number of blocks LA that are to be
calculated in advance.
Effect
M120 must be located in an NC block that also contains radius
compensation RL or RR. M120 is then effective from this block until
n radius compensation is canceled, or
n M120 LA0 is programmed, or
n M120 is programmed without LA.
n
another program is called with PGM CALL
M120 becomes effective at the start of block.
Limitations
n
After an external or internal stop, you can only re-enter the contour
with the function RESTORE POS. AT N.
n
If you are using the path functions RND and CHF, the blocks before
and after RND or CHF must contain only coordinates of the working
plane.
n If you want to approach the contour on a tangential path, you must
use the function APPR LCT. The block with APPR LCT must contain
only coordinates of the working plane.
n If you want to approach the contour on a tangential path, use the
function DEP LCT. The block with DEP LCT must contain only
coordinates of the working plane.