Allen-Bradley 1747-SN User Manual page 116

Rung 2:3
COPY THE BTW STATUS AREA TO AN INTEGER FILE ONLY WHEN A BTW IS IN PROGRESS.
THIS STATUS DATA WILL THEN BE USED THROUGHOUT THE PROGRAM AND WILL LIMIT THE
NUMBER OF M–FILE ACCESSES.
|
|
|
| BTW
| PENDING
| B3
|–+––––] [–––––+––––––––––––––––––––––––––––––––––––––––––+COPY FILE
| | 1 |
| | |
| | |
| | |
| | |
| | |
| | |
| | CHECK BTW |
| | STATUS |
| | B3 |
| +––––] [–––––+
| 3
Rung 2:4
UNLATCH THE BIT THAT CONTINUES TO CHECK THE BTW STATUS. WHEN A BTW IS
COMPLETE, THE DONE OR ERROR BIT IS SET. THE LADDER PROGRAM MUST THEN UNLATCH
THE ENABLE BIT, THEN WAIT FOR THE SN MODULE TO TURN OFF THE THE DONE/ERROR
BEFORE ANOTHER BTW TO THE SAME M–FILE LOCATION CAN BE INITIATED. THIS COMPLETES
ONE BTW CYCLE.
|
|
| VIRTUAL
| BTW DONE
| BIT
| N7:64
|–+––––]/[–––––+–––––––––––––––––––––––––––––––––––––––––––––––––––––––(U)–––––|
| | 13 |
| | |
| | |
| | VIRTUAL |
| | BTW ERROR |
| | BIT |
| | N7:64 |
| +––––]/[–––––+
| 12
RIO Block Transfer
BTW
STATUS
+COP–––––––––––––––+ |
+–|
|Source #M1:1.200| |
|Dest #N7:64| |
|Length 4| |
+––––––––––––––––––+ |
BIT
CHECK BTW
STATUS
B3
3
Publication 1747 6.6 - July 1996
5–39
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