1747-6.22, Backup Scanner User Manual
1747-6.22, Backup Scanner User Manual
1747-6.22, Backup Scanner User Manual
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RIO Block Transfer 7-127<br />
Rung 2:1<br />
Copy the BTW status area to a binary file which will be used throughout the program, only when a BTW is pending.<br />
This avoids accessing the M1 file multiple times during each program scan. Each time an instruction containing an<br />
M1 file bit, word or file is scanned by the processor, an immediate data transfer to bit, word or file is scanned by the<br />
processor, an immediate data transfer to the module occurs and therefore will impact the processor scan time.<br />
| SERVICE |<br />
| THE BTW |<br />
| STATUS/ |<br />
| BTW |<br />
| PENDING BTW STATUS |<br />
| B3:5 +COP---------------+ |<br />
|-+----] [-----+------------------------------------------+COPY FILE +-|<br />
| | 0 | |Source #M1:1.100| |<br />
| | | |Dest #B3:0| |<br />
| | | |Length 4| |<br />
| | | +------------------+ |<br />
| | | |<br />
| | CHECK BTW | |<br />
| | STATUS | |<br />
| | UNTIL DONE | |<br />
| | BIT IS OFF | |<br />
| | B3:5 | |<br />
| +----] [-----+ |<br />
| 1 |<br />
Rung 2:2<br />
Unlatch the bit that continues to check the BTW status. when a BTW is complete, the done bit is set. The ladder<br />
program must then unlatch the enable bit. Then wait for the SN module to turn off the done bit before another BTW to<br />
the same M-file location can be initialized. This is one complete BTW cycle.<br />
| | CHECK BTW |<br />
| VIRTUAL | STATUS |<br />
| BTW DONE | UNTIL DONE |<br />
| BIT | BIT IS OFF |<br />
| B3:0 B3:5 |<br />
|-+----]/[-----+-------------------------------------------------------(U)-----|<br />
| | 13 | 1 |<br />
| | | |<br />
| | VIRTUAL | |<br />
| | BTW ERROR | |<br />
| | BIT | |<br />
| | B3:0 | |<br />
| +----]/[-----+ |<br />
| 12 |<br />
Rung 2:3<br />
When a BTW successfully completes, unlatch the BTW enable bit. Also, unlatch the BTW pending bit and latch the<br />
bit that continures checking the BTW status until the SN module turns off the done bit.<br />
| SERVICE |<br />
| THE BTW |<br />
| VIRTUAL STATUS/ |<br />
| BTW DONE BTW |<br />
| BIT PENDING |<br />
| B3:0 B3:5 |<br />
|----] [--------------------------------------------------------+----(U)-----+-|<br />
| 13 | 0 | |<br />
| | | |<br />
| | | |<br />
| | VIRTUAL | |<br />
| | BTW ENABLE | |<br />
| | BIT | |<br />
| | B3:100 | |<br />
| +----(U)-----+ |<br />
| | 15 | |<br />
| | | |<br />
| | CHECK BTW | |<br />
| | STATUS | |<br />
| | UNTIL DONE | |<br />
| | BIT IS OFF | |<br />
| | B3:5 | |<br />
| +----(L)-----+ |<br />
| 1 |<br />
Publication <strong>1747</strong>-<strong>6.22</strong>