Rockwell Automation 8520-ARM2 9/Series CNC AMP Reference Manual Documentation Set - Manual (Page 341)

Spindle 1 Parameters
Chapter 12
12-13
Function
Use this parameter to define a precise mechanical zero position for the
spindle without requiring a mechanical adjustment of the encoder
mounting on the spindle shaft. When the spindle is homing, the control is
looking for the location of the encoder marker. After this marker is found,
the spindle continues on moving the angular distance specified with this
parameter. When this move is completed, the control calls its new rotary
position angle zero for all future orient and virtual C operations.
Specify the rotary distance (in degrees) from the encoder marker (or null)
to the “zero” angle position desired for the spindle. This distance defines
the location from the encoder null to the spindle orientation position that is
to be defined as home (orientation zero). If the location of the encoder
null position is the same as the position to be defined as spindle home,
enter a value of zero for this parameter.
The sign associated with this parameter simply allows this angular distance
to be specified as a positive or negative value. This sign has no effect on
the actual direction of rotation used to position to the calibration angle.
This direction of rotation is the same direction used to find the encoder
marker. Note that positive angles are typically measured from the encoder
null in the clockwise direction (M03 spindle direction).
Spindle Parameter
Number
1 [857]
Range
--360.000000 to 360.000000 degrees
Notes
This parameter can also be used to compensate for mechanical changes
that otherwise would have relocated the zero position for the spindle. For
example, the encoder orientation relative to the spindle position may
change when repairing gears or gear belts. Consequently the distance that
the axis moves from the encoder marker during homing may be different.
That difference can be measured and entered as, or added to, the Spindle
Marker Calibration value.
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.
This parameter must be set for each spindle axis.
12.9
Spindle Marker Calibration