Rockwell Automation GMLC Reference Manual - Manual (Page 725)

Publication GMLC-5.2 - November 1999
688 Using the RIO Adapter Option
Homing Axes
To directly home an axis from the PLC, select the axis by setting the
appropriate axis select bit (0 – 3) and the home selected axes bit (SLC
output 8, PLC output 10). To home more than one axis simultaneously, set
more than one axis select bit. Axes can be homed using this bit only while
there is no application program running in the motion controller. This bit
has no effect if it is set while the application program is running.
Note: Do not set the Home Selected Axes bit while the application
program in the motion controller is running.
The home selected axes bit turns feedback ON for the selected axes and
initiates homing using the power up homing configuration set for each
selected axis in the Homing page of the Configure Axis Use dialog box.
The power up homing configuration can be active, passive, or absolute,
depending on the requirements of the application.
The home selected axes input is edge-sensitive, not level-sensitive. The
motion controller must see a transition of this bit from 0 to 1 to initiate
homing. After homing has been initiated, the select axis bits and the home
selected axes bit are cleared.