Rockwell Automation 8520-ARM2 9/Series CNC AMP Reference Manual Documentation Set - Manual (Page 108)

Home Parameters
Chapter 5
5-6
Figure 5.1
Typical Homing Sequence
Encoder marker
Home limit switch
(1) (2) (3) (4)
Off On
(5) (6)
(9) (8) (7)
HOME
CALIBRATION
distance
Distance
to nearest
marker
Though not yet homed, the control picks up the encoder
marker and records feedback counts since last marker
Initial move to find home switch
1/8 1/8
Home tolerance exceeded area
Single Turn Absolute Encoder Considerations
In controls that incorporate single turn absolute encoders (8500 series
digital servo motors), the absolute single turns register of these encoders
must be reset to zero after the initial manual homing sequence has taken
place. The single turn absolute encoders should not have to be reset again
unless the encoder’s battery backup fails. The zero position of each
encoder will then be assigned the coordinate value entered for the Axis
Position after Homing parameter of each axis.