Siemens SINUMERIK 840D sl Programming Manual page 264

Motion commands
9.12 Tapping without compensating chuck (G331, G332)
Example 5: Gear stage cannot be changed → monitoring of gear stage
If the spindle speed is programmed in addition to the geometry in the G331 block when using
the second gear-stage data record, if the speed is not within the preset speed range (defined
by the maximum and minimum speed thresholds) of the active gear stage, it will not be
possible to change gear stages, because the path motion of the spindle and the infeed axis
(axes) would not be retained.
As in the example above, the speed and gear stage are monitored in the G331 block and
alarm 16748 is signaled if necessary.
Program code
N05 M40 S500
...
N55 SPOS=0
N60 G331 Z-10 K5 S800
Example 6: Programming without SPOS
Program code
N05 M40 S500
...
N50 G331 S800
N60 G331 Z-10 K5
Thread interpolation for the spindle starts from the current position, which is determined by
the previously processed section of the part program, e.g. if the gear stage was changed.
Therefore, it might not be possible to remachine the thread.
Note
Please note that when machining with multiple spindles, the drill spindle also has to be the
master spindle. SETMS(<spindle number>) can be programmed to set the drill spindle as
the master spindle.
264
Comment
; Gear stage 1 is selected.
; Gear stage cannot be changed, monitoring of spindle
speed 800 rpm with gear-stage data record 2: Gear
stage 2 should be active, alarm 16748 is signaled.
Comment
; Gear stage 1 is selected.
; Master spindle with second gear-stage data record: Gear
stage 2 is selected.
; Machine thread, spindle acceleration from second gear-stage
data record.
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
Fundamentals