Siemens SINUMERIK 840D sl Programming Manual page 198

Flexible NC programming
1.25 Subprogram technique
Note
For a subprogram return jump with a character string to specify the destination block search,
initially, a search is always made for a jump marker in the calling program.
If a jump destination is to be uniquely defined using a character string, it is not permissible
that the character string matches the name of a jump marker, as otherwise the subprogram
return jump would always be made to the jump marker and not to the character string (refer
to example 2).
General conditions
When making a return jump through several program levels, the SAVE instructions of the
individual program levels are evaluated.
If, for a return jump over several program levels, a modal subprogram is active and if in one
of the skipped programs the de-selection command MCALL is programmed for the modal
subprogram, then the modal subprogram remains active.
The programmer must carefully ensure that for a return jump over several program levels,
the program continues with the correct modal settings. This can be achieved, e.g. by
programming an appropriate main block.
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CAUTION
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
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