Manual Switchover Of The Basic System - Siemens SINUMERIK 840D sl Function Manual

References:
Programming Manual, Fundamentals; List of Addresses
NC-specific conversion factor
The default conversion factor in the machine data:
MD10250 $MN_SCALING_VALUE_INCH (conversion factor for switchover to inch system)
is set to 25.4 for converting from the metric to the inch system. By changing the conversion
factor, the control system can also be adapted to customer-specific systems of units.
Axis-specific conversion factor
The default conversion factor in the axis-specific machine data:
MD31200 $MA_SCALING_FACTOR_G70_G71 (conversion factor when G70/G71 is active)
is set to 25.4 for converting from the metric to the inch system. By changing the conversion
factor, the control system can also be adapted to customer-specific systems of units for each
axis.
7.3.2

Manual switchover of the basic system

General
The control system can operate with the metric or inch system. The initial setting of the system
of units (basic system) is defined in the following machine data:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC (basic system metric).
Depending on the basic system, all length-related data is interpreted either as metric or inch
measurements.
The relevant softkey on the HMI in the "Machine" operating area is used to change the system
of units of the controller.
The system of units is only switched over under the following supplementary conditions:
● MD10260 $MN_CONVERT_SCALING_SYSTEM=1
● MD20110 $MC_RESET_MODE_MASK, bit 0 is set in every channel.
● All channels are in the Reset state.
● Axes do not currently traverse with JOG, DRF, or PLC.
● Constant grinding wheel peripheral speed (GWPS) is not active.
Actions such as part program start or mode change are disabled while the system of units is
being switched over.
The actual change in the system of units is made by writing all the necessary machine data
and subsequently activating them.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
G2: Velocities, setpoint / actual value systems, closed-loop control
7.3 Metric/inch measuring system
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