Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 439)

Spindles
Chapter 17
17-3
For each spindle configured in a system, the control is equipped to perform
a spindle orient operation. This operation is used to rotate the spindle to a
given angle. Typically this may be used to orient the spindle for tool
positioning for special machining operations, position a mechanical chuck
for automatic chuck wrench operations, etc. This orient operation is not
the same as using a spindle as an axis for positioning. An orient operation
is performed separately from axis motions and can not be interpolated like
normal axis motions.
There are two types of spindle orients available. They are:
Open loop orient - The spindle does not use a feedback device for this
type of orient. The final destination of the spindle when performing an
open loop orient is determined by PAL. Typically there is some form of
hardware switch used to determine the spindle is at the proper position.
When the open loop orient is performed the spindle is turned at an AMP
defined RPM and in an AMP defined direction.
Closed loop orient - The spindle must be equipped with a feedback
device. The final destination of the spindle when performing a closed
loop orient may be determined in AMP, or entered in a program block
requesting an orient. When the closed loop orient is performed the
spindle is positioned at an AMP defined orient position. The direction
of the orient is as follows:
if the spindle is turning the orient will complete in the same
direction as the spindle is currently revolving. If the spindle is
turning faster than the maximum orient speed (as programmed in
AMP) it will first slow to the orient speed before performing the
orient.
if the spindle is not turning the orient will be performed in
whichever direction that will result in the spindle reaching the
required position using the shortest angular distance.
Important: A spindle orient is also sometimes automatically requested by
the control when performing some of the milling cycles. This milling
cycle orient orients to either the AMP defined position if using a closed
loop orient type or to the position defined as the open loop orient position
by hardware and PAL interface.
Important: In systems allowing multiple spindles (9/260 and 9/290), only
one M19 code can be in a block. If two or more M19 codes appear in one
block, e.g., M19.2 M19#, this error message appears, “ONLY ONE M19
ALLOWED PER BLOCK.”
17.2
Spindle Orientation (M19)