Siemens Sinumerik 840D sl Programming Manual page 209

Note
Path specification: Short designations
The following short designations can be used to specify the path:
• LOCAL_DRIVE: for local drive
• CF_CARD: for CompactFlash Card
• USB: for USB front connection
CF_CARD: and LOCAL_DRIVE: can be alternatively used.
Note
Execute from external source via USB drive
If external part programs are to be transferred from an external USB drive via a USB
interface, only the interface via X203 (with the name "TCU_1") can be used.
NOTICE
Execute from external source via USB FlashDrive (at the USB front connection)
It is not recommended to directly execute from a USB FlashDrive inserted at the front USB
port. This is because an interrupted connection to the USB FlashDrive while executing the
part program (as a result of contact problems, the USB drive falling out, interruption or
accidentally knocking or withdrawing it) immediately stops machining. The tool and/or
workpiece could be damaged.
Example
Execute from local drive
Main program:
Program code
N010 PROC MAIN
N020 ...
N030 EXTCALL ("ROUGHING")
N040 ...
N050 M30
External subprogram:
Program code
N010 PROC ROUGHING
N020 G1 F1000
N030 X= ... Y= ... Z= ...
N040 ...
...
...
N999999 M17
Job planning
Programming Manual, 02/2011, 6FC5398-2BP40-1BA0
Flexible NC programming
1.25 Subprogram technique
209