Rockwell Automation 8520-ARM2 9/Series CNC AMP Reference Manual Documentation Set - Manual (Page 340)

Spindle 1 Parameters
Chapter 12
12-12
These parameters are relevant only if your spindle provides position
feedback and is capable of orienting to a specific position.
Important: It is possible to perform coarse spindle orients without
position feedback through proper PAL programming and the use of
mechanical switches mounted on the spindle mechanism. These
parameters are not relevant for such an application.
The spindle orient feature (Figure 12.1) lets the control stop the spindle at
either a predefined angle set in AMP or a programmed angle. The spindle
orient feature is discussed in the Lathe and Mill Operation and
Programming Manuals.
Spindle Homing
Closed loop spindle orients require a marker be found on the spindle
encoder before the orient is performed. If the spindle has not found a
marker before an orient is requested (M19), a homing operation will be
initiated. (Note that spindle homing may also be forced when the spindle
enters the virtual C mode as discussed in chapter 28.) Spindle homing
consists of the spindle decelerating to the orient spindle RPM, and finding
the encoder marker (or null position). Once this position is found, the
spindle moves on to the spindle marker calibration point that determines
the location of the zero point of the spindle relative to the encoder marker
position. After this location is reached, the spindle moves to the location
requested in the M19 block. This homing operation is typically only
required once after every power cycle.
Important: Note that the use of a spindle with feedback must have only
one encoder marker per revolution of the spindle. If more than one
encoder marker is present, inconsistent homing results depending on which
marker is found first when the spindle homing operation is activated.
Figure 12.1
Parameters for Spindle Orient
ORIENT DIRECTION
Typically this is positive ( + )
as viewed from headstock
Encoder marker position
relative to spindle rotation 0 degree
ORIENT
INPOSITION
BAND
Typical
commanded
position
SPINDLE
MARKER
CALIBRATION
distance
12.8
Spindle Orienting
Parameters