Siemens SINUMERIK 840D Function Manual page 836

S1: Spindles
18.8 Spindle monitoring
In this case, a distinction is made between the following cases:
● Programmed speed too high
The programmed speed is higher than the configured maximum speed of the numerically
largest gear stage:
S... > MD35110 $MA_GEAR_STEP_MAX_VELO[<n>]
In this case, the highest gear stage is selected (according to MD35090
$MA_NUM_GEAR_STEPS).
● Programmed speed too low
The programmed spindle speed is less than the configured minimum speed of the first gear
stage:
S... < MD35120 $MA_GEAR_STEP_MIN_VELO[1]
In this case, the first gear stage is selected.
● Programmed speed = 0
When programming speed 0 (S0) the behavior depends on the configuration of the
minimum speed of the first gear stage MD35120 $MA_GEAR_STEP_MIN_VELO[1]:
– If MD35120 $MA_GEAR_STEP_MIN_VELO[1] = 0 is configured, then when
– If MD35120 $MA_GEAR_STEP_MIN_VELO[1] > 0 is configured, when
Effectiveness
Selecting the highest gear stage or the first gear stage for automatic gear stage selection (M40)
is active when programming spindle speeds S... using the part program, in synchronized actions
or when entering via PLC FC18.
For speed programming from the part program for tapping with G331, the behavior is also
supported for the second data set to select the gear stage (precondition:
MD35010 $MA_GEAR_STEP_CHANGE_ENABLE, bit 5 = 1).
Supplementary conditions
Enabling the gear stage change
The precondition for the function is that the gear stage change is generally enabled via machine
data:
MD35010 $MA_GEAR_STEP_CHANGE_ENABLE (assign parameters to the gear stage
change).
MD35090 $MA_NUM_GEAR_STEPS (number of gear stages set up)
Example
Automatic gear stage selection M40 is the basic setting after NC reset.
836
programming S0, the first gear stage is selected.
programming S0 no gear stage change is performed and the last gear stage remains
active. This means that it remains possible to stop the spindle with S0 (instead of M5)
without initiating a gear stage change.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA