Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 101)

Manual/MDI Operation Modes
Chapter 4
4-9
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 encoder marker.
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 the machine
homing operation has been conducted. Homing the axis should be the first
operation done on the control after power-up.
Figure 4.3
Machine Home
Machine coordinate
system zero point
+Z
+X
Machine
home
point
A
B
AMP-defined home
coordinates
X = A
Z = B
The following procedure describes how the control is homed manually by
using the pushbuttons on the MTB panel. Manual homing may 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: Automatic homing is available. Refer to page 14-12.
4.4
Manual Machine Homing