Rockwell Automation 1784-PM16SE SoftLogix Motion Card Setup and Configuration Manual - Manual (Page 304)

Publication 1784-UM003A-EN-P – June 2003
296 Motion Object Attributes
When this sequence is performed in the Active Homing Mode, the axis moves
in the specified Home Direction at the specified Home Speed until the home
switch is detected. The axis continues in the same direction at the Home Speed
until the first marker event is detected. The Home Position is assigned to the
axis position at the precise position where the marker was detected, and the
axis then decelerates to a stop. If Home Offset is non-zero, then the Home
Position will be offset from the point where the marker was detected by this
value. The controller then continues to move the axis to the Home Position at
the specified Home Speed using a trapezoidal move profile. By setting a Home
Offset greater than the deceleration distance, unidirectional motion to the
Home Position is insured. However, if the Home Offset value is less than the
deceleration distance, then the axis is simply decelerated to a stop. The axis
does NOT reverse direction to move to the Home Position. In this case, the
PC-bit leg of the associated MAH instruction is not set when the IP-bit leg is
cleared.
In the case where this homing sequence is performed on a rotary axis and the
Home Offset value is less than the deceleration distance when the home event
is detected, the control automatically adds one or more revolutions to the
move distance. This guarantees the resulting move to the Home Position is
unidirectional.
Passive Homing
Passive Immediate Home
This is the simplest passive homing sequence type. When this sequence is
performed, the controller immediately assigns the Home Position to the
current axis actual position. This homing sequence produces no axis motion.
Passive Home with Switch
This passive homing sequence is useful for when an encoder marker is not
available or a proximity switch is being used.
When this sequence is performed in the Passive Homing Mode, an external
agent moves the axis until the home switch is detected. The Home Position is
assigned to the axis position at the moment that the limit switch is detected. If
Home Offset is non-zero, then the Home Position will be offset from the
point where the switch is detected by this value.
Passive Home with Marker
This passive homing sequence is useful for single turn rotary and linear
encoder applications.