Inch/Metric Input Designation (G20, G21) - Siemens SINUMERIK 802D sl Programming Manual

Movement Control Commands
3.2 Determining the coordinate value input modes
G91;
Incremental
G90;
Absolute
Fig. 3-12
3.2.2

Inch/Metric input designation (G20, G21)

It is possible to select the dimension unit for the input data between "mm" and
"inch". For this selection, the following G codes are used.
Table 3-4
G20
G21
Command format
G20 and G21 should be specified at the beginning of a program in a block without
other commands. When the G code which selects the input dimension unit is
executed, the following values are processed in the selected dimension unit: sub-
sequent programs, offset amount, a part of parameters, a part of manual operation
and display.
G291;
G20;
Fig. 3-13
3-60
Y
Y
3
Y
Y
2
Y Y
1
Absolute/incremental commands (G90, G91)
Dimension unit selection G codes
G code
Input in "inch" system
Input in "mm" system
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·
·
Example pf programming
SINUMERIK 802D sl/840D/840D sl/840Di/840Di sl/810D ISO Milling (PGM) - - 04.07 Edition
+Y-axis
6
5
4
X X
4 5
X
1
X
2
X
3
Function
Designating the input in "inch" system
© Siemens AG 2007 All rights reserved
04.07
+X-axis
X
6
Group
06
06