Siemens SINUMERIK 840Di Function Manual page 1541

Fig. 2-7
Permanently defining the gear step with M41 to M45
The gear step can be permanently defined in the part program with M41 to M45.
If a gear step is specified by M41 to M45, which is not the same as the current (actual) gear
step, NC/PLC IS:
DB31, ... DBX82.3 (Change gear)
and
DB31, ... DBX82.0-82.2 (Set gear step A to C)
are set.
The programmed spindle speed (S value) then refers to this permanently defined gear step.
If a spindle speed is programmed, which exceeds the max. speed of the defined gear step,
the spindle speed is limited to the max. speed of the gear step:
MD35130 $MA_GEAR_STEP_MAX_VELO_LIMIT
and NC/PLC IS:
DB31, ... DBX83.1 (setpoint speed limited)
is set.
Spindles (S1)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Example for two "gear steps with overlapping speed ranges" for automatic gear step
change (M40)
Detailed Description
2.3 Configurable gear adaptation
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