Siemens SINUMERIK 840D sl Function Manual page 910

Detailed description
2.4 Frames
2.4.9 Subroutine return with SAVE
Settable frames G54 to G599
If the same G code is active on the subroutine return as in the subroutine call, then the active
settable frame is retained.
If this is not the case, the settable frame at the instant the subroutine was called is
reactivated (response as now).
The new response can be deactivated by setting bit 0 in machine data
MD10617 $MN_FRAME_SAVE_MASK
.
Basic frames $P_CHBFR[ ] and $P_NCBFR[ ]
The active total basic frame is retained on return from a subroutine.
The new response can be deactivated by setting bit 1 in machine data
MD10617 $MN_FRAME_SAVE_MASK
.
Programmable frame
The programmable frame is recreated when the subroutine return is carried out.
System frames $P_TRAFR, $P_SETFR, $P_EXTFR, $P_PARTFR, $P_TOOLFR, $P_WPFR,
$P_CYCFR
These system frames are not affected by the SAVE attribute. A compatibility machine data is
not provided.
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Basic logic functions: Axes, coordinate systems, frames (K2)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0