Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 130)

Preface MicroLogix 1000 Programmable Controllers User Manual
7–8
Comparison Instructions in the Paper Drilling Machine
Application Example
This section provides ladder rungs to demonstrate the use of comparison
instructions. The rungs are part of the paper drilling machine application example
described in appendix E. You will be adding an instruction to file 2 and beginning a
subroutine in file 7.
Adding to File 2
To begin you will need to return to the rungs first entered in chapter 6. One more
instruction needs to be added to the first rung to keep track of the drill life. This
rung is indicated below by the shading. Notice that text has also been added to the
rung comment.
Note Do not add this instruction if you are using a 16 I/O controller. Address O:0/6 is
only valid for 32 I/O controllers.
Rung 2:3
Starts the conveyor in motion when the start button is pressed.
However, there are other conditions that must also be met before we
start the conveyor. The are: the drill must be in its fully
retracted position (home); the drill bit must not be past its maximum
useful life. This rung also stops the conveyor when the stop button
is pressed or when the drill life is exceeded.
| START |Drill STOP |change | Machine |
| Button |Home LS Button |drill bit | RUN |
| |NOW | Latch |
| I:0 I:0 I:0 O:0 B3 |
|–+––––] [––––––––][–––––+––––]/[––––––––]/[––––––––––––––––––( )––––|
| | 6 5 | 7 6 0 |
| | Machine | |
| | RUN | |
| | Latch | |
| | B3 | |
| +––––] [––––––––––––––––+ |
| 0 |