Bidirectional Continuous Block Transfer Example - Allen-Bradley 1747-SN User Manual

5–38 RIO Block Transfer
Rung 2:0
CONFIGURE THE BT OPERATION TYPE, LENGTH AND RIO ADDRESS (R,G,S IN DECIMAL) AT
POWER–UP. BIT N7:50/7 MUST BE SET TO A "1" TO INDICATE A BTR AND BIT N7:53/7
MUST BE A LOGICAL "0" TO INDICATE A BTW OPERATION.
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| POWER–UP
| BIT
| S:1
|––––] [––––––––––––––––––––––––––––––––––––––––––––––+–+COPY FILE
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Rung 2:1
COPY THE BTR STATUS AREA TO AN INTEGER FILE ONLY WHEN A BTR IS IN PROGRESS.
THIS STATUS INFORMATION WILL THEN BE USED THROUGHOUT THE PROGRAM AND WILL LIMIT
THE NUMBER OF M–FILE ACCESSES.
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| BTR
| PENDING
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|–+––––] [–––––+––––––––––––––––––––––––––––––––––––––––––+COPY FILE
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| | CHECK BTR
| | STATUS
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| +––––] [–––––+
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Rung 2:2
UNLATCH THE BIT THAT CONTINUES TO CHECK THE BTR STATUS. WHEN A BTR 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 DONE/ERROR BIT
BEFORE ANOTHER BTR TO THE SAME M–FILE LOCATION CAN BE INITIATED. THIS IS ONE
COMPLETE BTR CYCLE.
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| VIRTUAL
| BTR DONE
| BIT
| N7:60
|–+––––]/[–––––+–––––––––––––––––––––––––––––––––––––––––––––––––––––––(U)–––––|
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| | VIRTUAL
| | BTR ERROR
| | BIT
| | N7:60
| +––––]/[–––––+
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Publication 1747 6.6 - July 1996

Bidirectional Continuous Block Transfer Example

The following rungs demonstrate a bidirectional continuous block
transfer. The BTR and BTW will each execute as fast as possible,
continuously and independently of one another.
15
B3
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B3 |
2
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12
BTR
CONTROL
+COP–––––––––––––––+
+–+–|
| |Source #N7:50| | |
| |Dest #M0:1.100| | |
| |Length 3| | |
| +––––––––––––––––––+ | |
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| BTW
| CONTROL
| +COP–––––––––––––––+ | |
+–+COPY FILE +–+ |
|Source #N7:53|
|Dest #M0:1.200|
|Length 3|
+––––––––––––––––––+
BTR STATUS
+COP–––––––––––––––+ |
|Source #M1:1.100| |
|Dest #N7:60| |
|Length
+––––––––––––––––––+ |
CHECK BTR
STATUS
B3
2
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