Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 318)

Coordinate Control
Chapter 11
11-2
The control has two types of coordinate systems:
machine coordinate system. This is often referred to as the absolute
coordinate system, which is unique to the individual grinding machine
work coordinate system. This is defined based on the coordinate
system used in the part drawing of a part to be ground by the machine
Programs are usually written based on the work coordinate system.
The machine coordinate system is the basic coordinate system set for every
CNC grinder. It is established after completion of the machine homing
operation. It cannot be offset or shifted in any way. Its position is
determined in AMP by your system installer.
Important: You must home the machine before you can activate any
coordinate system. The homing operation refers to the positioning of the
axes to a machine-dependent fixed position, which is called the machine
home. For more on machine homing, see page 4-11.
The zero point of the machine coordinate system is referenced from the
machine home point. This is done by assigning a coordinated location to
the machine home point. The home position for each axis can be given
any legal coordinates such as 15.00, -20.0000, or -2.256.
Once established, the machine coordinate system is not affected by a
control reset operation or any other programming or operator operation.
Figure 11.1
Machine Coordinate System, Home Coordinate Assignment
Chuck
Machine Coordinate System
zero point
+Z
+X
Mechanically fixed
Machine Home
point
15
10
12168-I
11.1
Machine (Absolute)
Coordinate System