Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 458)

Axis Motion
Chapter 12
12-86
Homing Axes Individually
This method requires that each axis be homed individually. When a
manual home operation is performed, a home request must be made to
each axis in the dual group on an individual method. Refer to chapter 4 for
details on how to request a manual home operation.
Homing Axes Simultaneously
This method allows a request for all axes in the dual group to be homed at
the same time. This does not mean that all axes reach home at the same
time. Keep in mind that your system installer can define different
feedrates and different home positions for each axis in the dual group.
With proper PAL programming, your system installer can configure all
axes in the dual axis group to home when the request is made to the master
axis. If this homing method is used, all unparked axes are homed together.
Refer to chapter 4 for details on how to request a manual home operation
and page 12-27 on how to request an automatic home operation (G28).
Axes in a dual axis group can be positioned using any of the normal
programming or manual motion operations. To position a dual axis, only
the master axis name can be requested. Requests to position a dual axis
can be made in manual, automatic, or MDI mode.
For absolute and incremental moves, regardless of the start-point, each axis
in the dual group reaches the requested position (or travel the requested
distance) at the same time. For absolute moves, this means individual axis
feedrates can be modified, depending on the distance each axis must travel
from start to end of the requested move.
Your system installer can assign different maximum positioning, external
deceleration, and rapid feedrate limitations for each axis in a dual axis
group. The control uses the slowest feedrate for each of these features
from any axis in the dual axis group.
12.13.3
Programming a Dual Axis