Application Example Programs
E–15
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| |
| +––––––––––––––––––+ |
Rung 7:4
Ensures that the operator cannot select a paper thickness of 0. If this
were allowed, the drill bit life calculation could be defeated
resulting in poor quality holes due to a dull drill bit. Therefore the
minimum paper thickness used to calculate drill bit wear is 1/4 in.
| debounced debounced |
| BCD BCD |
| value value |
| +EQU–––––––––––––––+ +MOV–––––––––––––––+ |
|–+EQUAL +–––––––––––––––––––––––––––+MOVE +–|
| |Source A N7:12| |Source 1| |
| | 0| | | |
| |Source B 0| |Dest N7:12| |
| | | | 0| |
| +––––––––––––––––––+ +––––––––––––––––––+ |
Reference
efesotomasyon.com - Allen Bradley,Rockwell,plc,servo,drive
