Siemens SINUMERIK 802D sl Function Manual page 355

Gear stage change
A new gear stage can only be selected when the spindle is stationary.
The spindle is stopped internally in the control if a gear stage change is requested. If the new
gear stage is preselected by M40 and spindle speed or M41 to M45, the IS "Set gear stage
A" to "...C" (V390x 2000.0 to .2) and the IS "Change gear" (V390x 2000.4) are set. At the
point when the IS "Oscillation speed" (V380x 2002.5) is enabled, the spindle decelerates to a
stop with the acceleration for oscillation or with the acceleration for speed control / position
control.
The next block in the part program after the gear stage change via M40 and S value or M41
to M45 is not performed (same effect as if the IS "Read-in disable" (V3200 0006.1) were
enabled).
When stationary the spindle (IS "Axis/spindle stationary" (V390x 0001.4)) can be activated
with the IS "Oscillation speed" (V380x.2002.5) (see Section "Spindle oscillation mode").
When the new gear stage is engaged, the PLC user sets the IS "Actual gear stage" (V380x
2000.0 to .2) and IS "Gear changed" (V380x 2000.3). The gear stage change is considered
completed (spindle mode "Oscillation mode" is deselected) and the spindle is switched to the
parameter block of the new actual gear stage. The spindle accelerates at the new gear stage
to the spindle speed last programmed (if M3 or M4 are active). The IS "Change gear" (V390x
2000.3) is reset by the NCK, which causes the PLC user to reset the IS "Gear changed"
(V380x 2000.3). The next block in the part program can be executed.
Typical time sequence for the gear stage change:
Turning, Milling, Nibbling
Function Manual, 11/2012, 6FC5397-1CP10-5BA0
Spindle (S1)
20.4 Gear stage change
355