Siemens SINUMERIK 840D sl Programming Manual page 537

used for the path of subprogram "SP_1" and is also not rewritten in the main program.
Therefore, the complete path has to be specified when subprogram "SP_2" is called.
Main program "MAIN"
Program code
N010 PROC MAIN
N020 ...
N030 EXTCALL("SP_1")
N030 EXTCALL("USB:WKS.DIR/WST1.WPD/SP_2")
N050 ...
N060 M30
Further information
EXTCALL call with absolute path name
If the subprogram exists under the specified path, it is executed with the EXTCALL call. If the
subprogram does not exist under the specified path, the program execution is aborted with the
EXTCALL call.
EXTCALL call with relative path name / without path name
In the event of an EXTCALL call with a relative path name or without a path name, the available
program memories are searched as follows:
1. If a path name is preset in SD42700 $SC_EXT_PROG_PATH, the data specified in
the EXTCALL call (program name or with relative path name) is searched for first, starting
from this path. The absolute path is obtained from linking the following characters:
– Default path specification in SD42700 $SC_EXT_PROG_PATH
– Separator "/"
– Path specification and subprogram name in the EXTCALL command
2. If the subprogram was not found under 1., the directories of the user memory are searched.
The search ends when the subprogram is found for the first time. If the subprogram is not found,
the program execution is aborted with the EXTCALL call.
Adjustable reload memory (FIFO buffer)
A reload memory is required for the execution of an external subprogram. The size of the reload
memory is preset with 30 kB and can only be changed by the machine manufacturer (using
MD18360 MM_EXT_PROG_BUFFER_SIZE).
Note
Subprograms with jump commands
For external subprograms that contain jump commands (GOTOF, GOTOB, CASE, FOR, LOOP,
WHILE, REPEAT, IF, ELSE, ENDIF etc.) the jump destinations must lie within the post loading
memory.
NC programming
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
Work preparation
3.2 Subprogram technique
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