Siemens SINUMERIK 840D sl Function Manual page 330

G2: Velocities, setpoint / actual value systems, closed-loop control
7.3 Metric/inch measuring system
The following machine data are automatically switched over consistently for all configured
channels:
● MD10240 $MN_SCALING_SYSTEM_IS_METRIC
● MD20150 $MN_GCODE_RESET_VALUES
Reset position
When the system of units is switched over, the reset position of the G group 13 is automatically
adapted.
● MD20150 $MC_GCODE_RESET_VALUES[12] = <current system of units>
Note
The availability of the softkey and, therefore, its functionality, can be configured using the
compatibility machine data:
MD10260 $MN_CONVERT_SCALING_SYSTEM
If several NCUs are linked by NCU-link, the switchover has the same effect on all linked NCUs.
If the requirements for a switchover are not fulfilled on one of the connected NCUs, no
switchover will take place on any of the NCUs. It is assumed that interpolations between several
NCUs will take place on the existing NCUs, whereby the interpolations can provide correct
results only if the same systems of units are used.
References:
Function Manual, Extended Functions; Several Control Panels on Multiple NCUs, Distributed
Systems (B3)
System data
When the system of units is switched over, from the user's viewpoint, all length-related
specifications are converted to the new system of units automatically.
This includes:
● Positions
● Feedrates
● Accelerations
● Jerk
● Tool offsets
● Programmable, settable and external zero offsets and DRF offsets
● Compensation values
● Protection zones
● Machine data
● Jog and handwheel factors
After the changeover, all of the above data is available in physical quantities.
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Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions