Rockwell Automation 8520-ARM2 9/Series CNC AMP Reference Manual Documentation Set - Manual (Page 106)

Home Parameters
Chapter 5
5-4
9. If the distance to nearest null is out--of--tolerance, then the home
procedure is aborted and an error message is displayed in yellow
“axis names HOME TOLERANCE EXCEEDED”. Refer to
Figure 5.1 and Figure 5.2 for an example.
10. If the distance from the null is within tolerance, the distance to null is
added to the Home Calibration parameter to calculate the axis home
position.
11. The axis moves at Home Speed from Limit Switch to the calculated
home position (this can be in either direction, depending on the result
of the previous calculations).
12. The control defines this position as the home position for the axis,
and assigns it the coordinate value entered for the parameter
Axis Position after Homing.
A typical homing sequence is illustrated in Figure 5.1. This figure
assumes that the value entered for the AMP parameter Dir. to Move Off
Limit Switch is opposite the direction moved to the switch (opposite of
G28 Direction to Home for automatic homing). It also assumes that the
sum of the distance to the nearest marker and the Home Calibration
distance, result in a move in the same direction as Dir. to Move Off
Limit Switch.
The following procedure applies to revision 12.x or earlier. Refer to
page 5-2 if the software revision of your system is 13.x or greater:
1. Set the Mode Select switch to “Manual,” and the Jog Select switch to
“Home” (assuming the Standard MTB Panel is being used).
2. Press the appropriate Axis/Direction button to move the axis in the
direction of the home limit switch. Initial speed for this move can be
selected through the use of the jog speed and feedrate override
switches.
Once the homing sequence is initiated, the jog speed switch has no
effect on the speed of the axis. However, the feedrate override switch
still effects speed.
ATTENTION: Some mechanical switches will turn “OFF” at a
different location when approached from different directions.
In those cases, it is essential that the home limit switch be
approached from the same direction every time the axis is
homed. This can be assured by proper switch positioning, PAL
programming, AMP programming and/or operator instruction.