Reference – Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers User Manual

Page 361

Application Example Programs

E–11

Rung 4:6
Signals the main program (file 2) to initiate a drilling sequence. The
high-speed counter has already stopped the conveyor at the correct
position using its high preset output pattern data (clear O:0/0). This
occurred within microseconds of the high preset being reached (just
prior to entering this high-speed counter interrupt subroutine). The
drill sequence subroutine resets the drill sequence start bit and sets
the conveyor drive bit (O:0/0) upon completion of the drilling
sequence.

| interrupt occurred | Drill Sequence Start |
| due to high preset reached | |
| C5:0 B3 |
|––––] [––––––––––––––––––––––––––––––––––––––––––––––––––––––(L)–––––|
| IH 32 |

Rung 4:7

| |
|–––––––––––––––––––––––––––––––+END+–––––––––––––––––––––––––––––––––|
| |

Rung 6:0
This section of ladder logic controls the up/down motion of the drill
for the book drilling machine. When the conveyor positions the book
under the drill, the DRILL SEQUENCE START bit is set. This rung uses
that bit to begin the drilling operation. Because the bit is set for
the entire drilling operation, the OSR is required to be able to turn
off the forward signal so the drill can retract.

Rung 6:1
When the drill has drilled through the book, the body of the drill
actuates the DRILL DEPTH limit switch. When this happens, the DRILL
FORWARD signal is turned off and the DRILL RETRACT signal is turned on.
The drill is also retracted automatically on power up if it is not
actuating the DRILL HOME limit switch.

| Drill Drill |
| Depth LS Forward |
| I:0 O:0 |
|–+––––] [––––––––––––––––+––––––––––––––––––––––––––––+––––(U)–––––+–|
| | 4 | | 3 | |
| | 1’st |Drill | | Drill | |
| | Pass |Home LS | | Retract | |
| | S:1 I:0 | | O:0 | |
| +––––] [––––––––]/[–––––+ +––––(L)–––––+ |
| 15 5 2 |

Reference