Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 115)

Manual/MDI Operation Modes
Chapter 4
4-11
The machine home return operation means the positioning of a specified
linear or rotary axis to a machine-dependent fixed position, which is called
the machine home. This position is established via a home limit switch
mounted on the machine and the marker on your feedback device.
The execution of machine home establishes the machine coordinate
system. Since all of the AMP assigned work coordinate systems and all of
the programmable zones are referenced from the zero point of the machine
coordinate system, none of these features are available until you have
conducted the machine homing operation. Homing the axis should be the
first operation done on the control after power has been turned on.
Figure 4.4
Machine Home
Machine coordinate
system zero point
+Z
+X
Machine home
point
A
B
AMP defined home
coordinates
X = A
Z = B
12002-I
The following procedure describes how you home the control manually by
using the pushbuttons on the standard MTB panel. Manual homing can be
different for some machines depending on the PAL program written by
your system installer.
Important: When a homing request is made the feedback device for the
axis (typically an encoder) must encounter at least one marker before
tripping the homing limit switch. If the axis is close to the home limit
switch you should jog the axis away from this switch before attempting a
homing operation.
Important: An automatic homing feature is available and is executed by
programming a G28 code. For details, see chapter 12.
4.7
Manual Machine Homing