Allen-Bradley 1747-SN - Page 118

5–41RIO Block Transfer
Publication 17476.6 - July 1996
Rung 2:7
WHEN A BTW SUCCESSFULLY COMPLETES, UNLATCH THE BTW ENABLE BIT AND THE BTW
PENDING BIT TO COMPLETE A BTW SEQUENCE. ALSO, LATCH THE BIT THAT CONTINUES
CHECKING THE BTW STATUS UNTIL THE SN MODULE TURNS THE DONE BIT OFF.
| |
| |
| VIRTUAL |
| BTW DONE BTW |
| BIT PENDING |
| N7:64 B3 |
|––––] [––––––––––––––––––––––––––––––––––––––––––––––––––––––––+––––(U)–––––+–|
| 13 | 1 | |
| | | |
| | | |
| | VIRTUAL | |
| | BTW ENABLE | |
| | BIT | |
| | N7:53 | |
| +––––(U)–––––+ |
| | 15 | |
| | | |
| | | |
| | | |
| | CHECK BTW | |
| | STATUS | |
| | B3 | |
| +––––(L)–––––+ |
| 3 |
Rung 2:8
WHEN A BTW UNSUCCESSFULLY COMPLETES, BUFFER THE ERROR CODE AND UNLATCH THE BTW
ENABLE BIT AND THE BTW PENDING BIT. ALSO, LATCH THE CHECK BTW STATUS BIT IN
ORDER TO CONTINUE READING THE STATUS INFORMATION FROM THE SCANNER UNTIL IT
TURNS OFF THE ERROR BIT, COMPLETING THE HAND–SHAKE PROCESS.
| |
| |
| VIRTUAL |
| BTW ERROR BTW ERROR |
| BIT CODE |
| N7:64 +MOV–––––––––––––––+ |
|––––] [––––––––––––––––––––––––––––––––––––––––––––––+–+MOVE +–+–|
| 12 | |Source M1:1.203| | |
| | | *| | |
| | |Dest N7:1| | |
| | | 0| | |
| | +––––––––––––––––––+ | |
| | | |
| | | |
| | | |
| | BTW | |
| | PENDING | |
| | B3 | |
| +––––(U)–––––––––––––––+ |
| | 1 | |
| | | |
| | | |
| | | |
| | | |
| | | |
| | VIRTUAL | |
| | BTW ENABLE | |
| | BIT | |
| | N7:53 | |
| +––––(U)–––––––––––––––+ |
| | 15 | |
| | | |
| | | |
| | | |
| | CHECK BTW | |
| | STATUS | |
| | B3 | |
| +––––(L)–––––––––––––––+ |
| 3 |