Siemens SINUMERIK 840D Function Manual page 779

Process sequence of the gear stage change
If the new gear stage is preselected, the following sequence is implemented:
1. Changeover sequence
The two following NC/PLC interface signals are set:
DB31, ... DBX82.0-82.2 (setpoint gear stage A to C)
DB31, ... DBX82.3 (change over gear stage)
In accordance with the point at which NC/PLC IS:
DB31, ... DBX18.5 (oscillation speed)
is set, the spindle decelerates to a standstill at the acceleration for oscillation or at the
acceleration for speed control / position control.
Oscillation can be activated at the latest when the spindle reaches a standstill:
DB31, ... DBX61.4 (axis/spindle stationary)
with NC/PLC IS:
DB31, ... DBX18.5 (oscillation speed).
In principle, the new gear stage can also be engaged without oscillation
When the new gear stage is engaged, the following NC/PLC interface signals are set by the
PLC program:
DB31, ... DBX16.0-16.2 (actual gear stage A to C)
DB31, ... DBX16.3 (gear is changed)
2. End of gear stage change
The gear stage change is treated as completed (spindle operation type "oscillation mode"
is deselected), if the following NC/PLC interface signal is set:
DB31, ... DBX16.3 (gear is changed)
The new actual gear stage is changed to the servo and interpolation parameter set when the
motor is stationary.
With NC/PLC interface signal:
DB31, ... DBX16.3 (gear is changed)
is used to communicate to the NC that the new gear stage is valid and the oscillation mode
can be completed.
The NC/PLC interface signal:
DB31, ... DBX82.3 (change gear)
is reset by the NC,
which causes the PLC program to reset NC/PLC IS:
DB31, ... DBX16.3 (gear changed).
In this case, it does not matter whether NC/PLC IS:
DB31, ... DBX18.5 (oscillation mode)
is still set.
The actual gear stage, which should correspond to the set gear stage, is relevant
for selecting the parameter set.
If this is not the case, then Alarm 22010 :
MD11410 $MN_SUPPRESS_ALARM_MASK, Bit 3 = 0
is output.
Following acknowledgment of gear stage change via the PLC
with NC/PLC IS:
DB31, ... DBX16.3 (gear changed)
the spindle is in speed control mode (DB31, ... DBX84.7).
Further information
For further instructions on signal exchange between PLC and NC, see Function Manual
Basic Functions; Diverse NC/PLC interface signals and functions.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
S1: Spindles
18.4 Configurable gear adaptations
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