Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) - Manual (Page 446)

Appendix E
Application Example Programs
E–3
Drill Mechanism Operation
When the operator presses the start button, the drill motor turns on. After the
book is in the first drilling position, the conveyor subroutine sets a drill
sequence start bit and the drill moves toward the book. When the drill has
drilled through the book, the drill body hits a limit switch and causes the drill
to retract up out of the book. When the drill body is fully retracted, the drill
body hits another limit switch indicating that it is in the home position.
Hitting the second limit switch unlatches the drill sequence start bit and
causes the conveyor to move the book to the next drilling position.
Conveyor Operation
When the start button is pressed, the conveyor moves the books forward. As
the first book moves close to the drill, the book trips a photo-eye sensor.
This tells the machine where the leading edge of the book is. Based on the
position of the selector switch, the conveyor moves the book until it reaches
the first drilling position. The drill sequence start bit is set and the first hole
is drilled. The drill sequence start bit is now unlatched and the conveyor
moves the same book to the second drilling position. The drilling process is
repeated until there are the desired holes per book. The machine then looks
for another book to break the photo-eye beam and the process is repeated.
The operator can change the number of drilled holes by changing the selector
switch.
Drill Calculation and Warning
The program tracks the number of holes drilled and the number of inches of
material that have been drilled through using a thumbwheel. The
thumbwheel is set to the thickness of the book per 1/4 inch. (If the book is 1
1/2 inches thick, the operator would set the thumbwheel to 6.) When 25,000
inches have been drilled, the Change Drill Soon pilot light turns on. When
25,500 inches have been drilled, the Change Drill Soon pilot light flashes.
When 26,000 inches have been drilled, the Change Drill Now pilot light
turns on and the machine turns off. The operator changes drill bits and then
resets the internal drill wear counter by turning the Drill Change Reset
keyswitch.