Siemens SINUMERIK 840D sl Function Manual page 326

G2: Velocities, setpoint / actual value systems, closed-loop control
7.3 Metric/inch measuring system
The following length-related data is displayed in the programmed system of units:
● Data in the workpiece coordinate system
Reading in part programs from external sources
If part programs, including data sets (zero offsets, tool offsets, etc.), programmed in a system
of units other than the basic system are read in from an external source, the initial setting must
first be changed in machine data MD10240.
NC/PLC interface signals
In the case of NC/PLC interface signals containing dimension information, e.g. feedrate for
path and positioning axes, data exchange is carried out with the PLC in the configured basic
system.
G functions G700/G710
The G functions G700/G710 extend the functionality of G70/G71 as follows:
1. The feedrate is interpreted in the programmed system of units:
– G700: length parameters [inch]; feedrates [inch/min]
– G710: length parameters [mm]; feedrates [mm/min]
The programmed feedrate is modal and therefore remains active after subsequent G70/G71/
G700/G710 commands. If the feedrate is to apply in the new G70/G71/G700/G710 context,
it must be re-programmed.
2. System variables and machine data specifying lengths in the part program are read and
written in the programmed system of units.
Differences during the reading and writing of machine data and system variables
The following differences exist between G70/G71 and G700/G710 in terms of reading and
writing machine data and system variables in the part program:
● G70/G71: Reading and writing takes place in the configured basic system.
● G700/G710: Reading and writing is performed in the configured system of units.
Example
The following part program is executed with an initial metric state:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC = 1
Program code
N100 R1=0 R2=0
N120 G01 G70 X1 F1000
N130 $MA_LUBRICATION_DIST[X]=10
N150 IF ($AA_IW[X] > $MA_LUBRICATION_DIST[X])
N160
326
R1=1
Comment
; Programmed system of units: inch
; MD=10 [mm] (basic system)
; [mm] > [mm] (basic system)
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions