Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set User Manual
Page 361
Chapter 11
Coordinate Control
11-45
Example 11.14
Absolute vs. Incremental Commands
Absolute Command
Incremental Command
G90X20.Z10.;
G91X10.Z-25.;
Figure 11.26
Results of Example 11.14
20
10
X
Z
Start point
End point
10
35
12181-I
You can program a G70 to select the inch system or a G71 to select the
metric system. These unit system G codes should be among the first
blocks written in a program.
Both G70 and G71 are modal, and cancel each other. The default unit
system selected by the control at power-up, end of program (M02, M30, or
M99) and control reset is determined in AMP by your system installer.
The currently active unit system is usually displayed on the screen for
softkey level 1 in lines 3 or 4 between the [ ] symbols. If the screen
selected for display of softkey level 1 is the status screen, the active system
G code (G71 or G70) is displayed among the active system G codes.
Following is a list of some of the functions that are affected by the active
unit system (inch or metric):
Position commands
Feedrate commands
Axis feed amount for fixed amount feed operation
Unit system for hand pulse generator (HPG)
11.10
Inch/Metric Modes (G70,
G71)