Siemens SINUMERIK 828D Function Manual page 1297

• If a spindle speed is programmed and it is more than the maximum speed of the permanently defined gear
stage (MD35130 $MA_GEAR_STEP_MAX_VELO_LIMIT), then the speed is decreased to this limit and the
following NC/PLC interface signal is set:
DB31, ... DBX83.1 (Setpoint speed restricted)
• If a spindle speed is programmed and it is less than the minimum speed of the permanently defined gear
stage (MD35140 $MA_GEAR_STEP_MIN_VELO_LIMIT), then the speed is increased to this minimum and
the following NC/PLC interface signal is set:
DB31, ... DBX83.2 (Setpoint speed restricted)
Block change
When programming the gear stage change in the part program, the gear stage change set remains active until
the gear stage change is aborted by PLC.
This corresponds to the effect as if the following NC/PLC interface signal were set:
DB21, ... DBX6.1 (read-in disable)
Specification of gear stage via PLC with FC18
The gear stage change can also be performed by function block FC18 during a part program, in the reset state or
in all operating modes.
If the speed and direction of rotation is specified with FC18, the NC can be requested to select the gear stage as
appropriate for the speed. This corresponds to an automatic gear stage change with M40.
The gear stage is not changed if:
• the spindle is positioned via FC18.
• the spindle is traversed in the axis mode.
Further instructions on function block FC18 can be found under:
References:
Function Manual Basic Functions; PLC Basic Program (P3)
Specification of a gear stage in synchronized actions
The gear stage change can be requested by synchronized actions using:
• DO M40 S...
Automatic gear stage selection to the programmed speed S...
• DO M41... M45
Direct selection of gear stages 1 ... 5
• DO M70
For MD35014 $MA_GEAR_STEP_USED_IN_AXISMODE = 1 ... 5
(see "Configurable gear step in M70 [Page 1320]")
The gear stage is not changed if:
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
S1: Spindles
16.4 Configurable gear adaptation
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