Siemens SINUMERIK 840D sl Function Manual page 408

Detailed description
2.2 Metric /inch measuring system
2.2.2 Conversion of basic system by parts program
Conversion factor
The factor for the inch to metric conversion for the data input and output can be adapted via
the following machine data:
MD10250 $MN_SCALING_VALUE_INCH (conversion factor for switchover to inch system)
Note
The machine data element is not visible unless the password of protection level "Siemens" is
set.
By changing the default value, the control can be adapted to a customerspecific measuring
system.
When programming, it is possible to change over between measuring systems for some
workpiece-related specifications with G70/G71/G700/G710. The data that can be influenced
by G70/G71/G700/G710 is described in the Programming Guide.
The basic position G70/G71/G700/G710 can be assumed channel-specifically via the initial
setting (reset) of the G groups in the machine data:
MD20150 $MC_GCODE_RESET_VALUES[12]
.
When changing the measuring system via the relevant soft key on the HMI, these initial
settings are automatically predefined to appropriate settings for the new measuring system
with G700 or G710.
With the axis-specific machine data:
MD31200 $MA_SCALING_FACTOR_G70_G71
(factor for converting values with active G70/G71/G700/G710)
can be used to freely select the conversion factor between metric and inch conversion with
G70/G71/G700/G710 programming.
The controller can be adapted to a customized measuring system by changing the
predefined settings. The factor only takes effect if parts program programming differs from
the initial state.
Example:
Initial state: inch; (MD10240 $MN_SCALING_SYSTEM_IS_METRIC=0)
Parts program:
N15 G70
N20 G71
The current setting (selected with G70/G71) and the initial state can be the same or differ at
any given time. The current setting is channelspecific, the initial state applies to all channels.
20
; Factor is not effective, since the setting is exactly the same as the initial
state.
; Factor is effective.
Basic logic functions: Velocities, Setpoint/Actual Value Systems, Closed-Loop Control (G2)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0