HEIDENHAIN TNC 426B (280 472) ISO programming - Manual (Page 258)

9 Programming: Subprograms and Program Section Repeats 242
9.1 Mar
king Subpr
ogr
ams and Pr
ogr
am Section Repeats;
9.2 Subprograms
9.1 Marking Subprograms and
Program Section Repeats
Subprograms and program section repeats enable you to program a
machining sequence once and then run it as often as desired.
Labels
The beginnings of subprograms and program section repeats are
marked in a part program by G98 labels.
A label is identified by a number between 1 and 254. Each label can
be set only once with G98 in a program.
If a label is set more than once, the TNC sends an error
message at the end of the G98 block.
For the TNC 426, TNC 430:
With very long programs, you can limit the number of
blocks to be checked for repeated labels with MP7229.
Label 0 (G98 L0) is used exclusively to mark the end of a
subprogram and can therefore be used as often as desired.
9.2 Subprograms
Operating sequence
1 The TNC executes the part program up to the block in which a
subprogram is called with Ln.0. n can be any label number
2 The subprogram is then executed from beginning to end. The
subprogram end is marked with G98 L0.
3 The TNC then resumes the part program from the block after the
subprogram call Ln.0.
Programming notes
■ A main program can contain up to 254 subprograms.
■ You can call subprograms in any sequence and as often as
desired.
■ A subprogram cannot call itself.
■ Write subprograms at the end of the main program (behind the
block with M2 or M30).
■ If subprograms are located before the block with M02 or M30,
they will be executed at least once even if they are not called.
% ...
L1,0
G00 Z+100 M2
G98 L1 *
G98 L0 *
N99999 % ...
Lkap9.pm6 29.06.2006, 08:07 242