Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 320)

Coordinate System Offsets
Chapter 11
11-4
When cutting a workpiece using a part program made from a part drawing,
it is desirable to match the zero point on the coordinate system of the part
drawing with the zero point of the work coordinate system.
As shown in the illustrations in Figure 11.3, the work coordinate system is
established by programming the distance between the desired zero point of
the work coordinate system and the zero point of the machine coordinate
system.
Figure 11.3
Work Coordinate System
Zero point on the
work coordinate
system
Workpiece
Workpiece
Table
Zero point on the
part drawing
Tool position at machine
coordinate zero point
X distance
to be designated
Z distance
to be designated
Y distance
to be designated
Y
Y
Z
Z
X
X
There are 9 preset work coordinate systems selectable using G54 - G59.3.
The required work coordinate system can be selected by specifying any of
these G--codes in the program.
Work coordinate systems called out by G54 - G59.3 have zero points that
are entered in a work coordinate system table (see section 3.3). These zero
points are in the form of offset values from the machine coordinate system
zero point.
11.2
Preset Work Coordinate
Systems (G54-59.3)