Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 177)

Using Data Handling Instructions
9–29
Rung 7:3
Converts the BCD thumbwheel value from BCD to integer. This is done
because the controller operates upon integer values. This rung also
”debounces” the thumbwheel to ensure that the conversion only occurs
on valid BCD values. Note that invalid BCD values can occur while the
operator is changing the BCD thumbwheel. This is due to input filter
propagation delay differences between the 4 input circuits that
provide the BCD input value.
| 1’st previous debounced |
| pass scan’s BCD value |
| bit BCD input |
| value |
| S:1 +EQU–––––––––––––––+ +FRD–––––––––––––––+ |
|–+––]/[––––––+EQUAL +–+–––––––+FROM BCD +–+––+–|
| | 15 |Source A N7:13| | |Source N7:14| | | |
| | | 0| | | 0000| | | |
| | |Source B N7:14| | |Dest N7:12| | | |
| | | 0| | | 0| | | |
| | +––––––––––––––––––+ | +––––––––––––––––––+ | | |
| | | Math Math | | |
| | | Overflow Error | | |
| | | Bit Bit | | |
| | | S:0 S:5 | | |
| | +––––] [–––––––––(U)–––––––––+ | |
| | 1 0 | |
| | this | |
| | scan’s | |
| | BCD input | |
| | value | |
| | +MOV–––––––––––––––+ | |
| +–––––––––––––––––––––––––––––––––––––––––––+MOVE +–+ |
| |Source N7:14| |
| | 0| |
| |Dest N7:13| |
| | 0| |
| +––––––––––––––––––+ |
➀
This rung accesses I/O only available with 32 I/O controllers. Therefore, do not include this rung if you are using
a 16 I/O controller.
Programming