Metric/Inch Measuring System; Conversion Of Basic System By Part Program - Siemens SINUMERIK 840D sl Function Manual

7.3

Metric/inch measuring system

7.3.1

Conversion of basic system by part program

Programmable switchover of the system of units
The basic system can be switched over within a part program via the G functions G70/G71/
G700/G710 (G group 13). The programmed system of units (G70/G71/G700/G710) and the
basic system may be identical or different at any time. Switchover of the system of units within
a particular section of the part program could, for example, be used to machine an inch thread
on a workpiece within a metric basic system.
The following section of the part program is executed in "metric" in the basic system:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC = 1
Program code
N100 G71
....
N200 G70
...
N300
...
Initial state of the G functions
The initial state for the G functions is set for each channel in the following machine data:
MD20150 $MC_GCODE_RESET_VALUES[12] (reset position for G group 13)
When the system of units is changed via the HMI user interface, the reset position is
automatically preset for compatibility with the new system of units with G700 or G710.
Displaying length-related data on the HMI
Length-related data are displayed in the parameterized basic system on the HMI:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC (basic system metric)
The following length-related data is displayed in the configured basic system:
● Machine data
● Data in the machine coordinate system
● Tool data
● Zero offsets
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
G2: Velocities, setpoint / actual value systems, closed-loop control
Comment
; Switchover to metric machining
; The conversion factor does not come into effect because the
programmed
; system of units does not differ from the basic system
; Metric machining
; Switchover to machining in inches
; The conversion factor comes into effect
; Machining in inches
; Switchover to metric machining
; Metric machining
7.3 Metric/inch measuring system
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