Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 325)

Coordinate System Offsets
Chapter 11
11-9
Figure 11.7
Results of Example 11.3
Tool position
G54 Work coordinate system
after changing table value
Machine coordinate system zero point
20 30 40 50
G54 Work
coordinate system
X
Y
Y
Y
X
X
15
25
15 25
20
30
40
50
The external offset allows all work coordinate system zero points to be
shifted simultaneously, relative to the machine coordinate system. This
offset can compensate for part positioning shifts that result when a
different tool is installed. It can also compensate for tool position shifts
that result from a different tool fixture.
The external offset can also be used to match the work coordinate systems
on mechanically different machines. The machines can then use the same
part program with the same G54-G59.3 coordinate values. This allows
part programs to be less machine dependant.
Four methods are available to modify the external offset:
Method: Active Immediately
after block execution
Active next Cycle Stop Active next re-home or
power cycle
Programming a G10 X
System installer PAL offset X
Manually through table X
Paramacro Programming X
11.3
Work Coordinate System
External Offset