Btr And Btw Control Logic Examples; Block Transfer Read Control Logic Example - Allen-Bradley 1747-SN User Manual

BTR and BTW Control
Logic Examples
Rung 2:0
CONFIGURE THE BTR OPERATION TYPE, LENGTH AND RIO ADDRESS AT POWER–UP. BIT
B3:100/7 MUST BE SET PRIOR TO GOING TO RUN TO INDICATE A BTR 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 A BINARY FILE WHICH WILL BE USED THROUGHOUT THE
PROGRAM. THIS AVOIDS ADDRESSING THE M1 FILE MULTIPLE TIMES DURING EACH PROGRAM
SCAN. EACH TIME AN INSTRUCTION CONTAINING AN M1 FILE BIT, WORD OR FILE IS
SCANNED BY THE PROCESSOR, AN IMMEDIATE DATA TRANSFER TO THE MODULE OCCURS AND
THEREFORE WILL IMPACT THE OVERALL PROCESSOR SCAN TIME.
| SERVICE
| THE BTR
| STATUS/
| BTR
| PENDING
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|–+––––] [–––––+––––––––––––––––––––––––––––––––––––––––––+COPY FILE
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| | CHECK BTR
| | STATUS
| | UNTIL DN
| | OR ER BIT
| | IS OFF
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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 BIT IS SET. THE LADDER PROGRAM MUST THEN UNLATCH THE ENABLE
BIT, THEN WAIT FOR THE SN MODULE TO TURN OFF THE DONE 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
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|–+––––]/[–––––+–––––––––––––––––––––––––––––––––––––––––––––––––––––––(U)–––––|
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| | VIRTUAL
| | BTR ERROR
| | BIT
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| +––––]/[–––––+
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The following pages contain generic BTR and BTW control logic
examples. Refer to chapter 7, Application Examples for specific
product applications using BT examples.

Block Transfer Read Control Logic Example

15
B3:5
0 |
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B3:5 |
1
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B3:0
13 |
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B3:0 |
12
RIO Block Transfer
BTR
CONTROL
+COP–––––––––––––––+ |
+–|
|Source #B3:100| |
|Dest #M0:1.100| |
|Length 3| |
+––––––––––––––––––+ |
BTR STATUS
+COP–––––––––––––––+ |
+–|
|Source #M1:1.100| |
|Dest #B3:0| |
|Length 4| |
+––––––––––––––––––+ |
CHECK BTR
STATUS
UNTIL DN
OR ER BIT
IS OFF
B3:5
1
Publication 1747 6.6 - July 1996
5–23
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