Siemens SINUMERIK 840D sl Programming Manual page 528

Work preparation
3.2 Subprogram technique
Note
The data definition area at the start of the subprogram is only executed once when executing
the block with the programmed MCALL call. For the following subprogram calls, after the
traversing blocks, the data definition area is no longer executed. This means that a value
assigned in the definition of a local user variable (LUD) is no longer available after the first call,
but the value that was last written in the cycle. The variable is not recreated after the first call
but keeps the last value from the previous call. To work around this response, we recommend
that the LUD definition and the value assignment are separated from one another, and the
value assignment is programmed in a dedicated block after the data definition area.
NOTICE
Modal subprogram calls without path motion
In the following situations the modal subprogram is also called without programming path
motion:
● Programming addresses S or F if G0 or G1 is active.
● If G0 or G1 were programmed alone in the block or with additional G commands.
Syntax
MCALL <program name>
...
MCALL
Meaning
MCALL <program
name>:
<program name>:
MCALL:
Boundary conditions
ASUB
If the part program processing is interrupted by an ASUB (see Chapter "Interrupt routine
(ASUB) (Page 539)"), then no modal subprogram calls are executed in this ASUB.
If an ASUB is started in the "Reset" channel state, then it behaves just like a normal part
program with regard to the modal subprogram calls.
Tool change cycle
If the "Modal subprogram call" function is deselected during the tool change cycle, note that the
tool change cycle is called implicitly, even after a block search, via the search ASUB, or
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Activate the "Modal subprogram call" function
Name of subprogram
The "Modal subprogram call" function is deactivated with MCALL without
specification of a program name.
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
NC programming