Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 86)

Chapter
Programming Block-Transfers 5
5 -12
You can use this ladder logic program with PLC-5/250 Family processors.
This program assumes that your application requires a single
block-transfer-read (BTR) and block-transfer-write (BTW) to pass data
between the processor and the BASIC module (transfer of 64 words or
less). If the transferred data exceeds 64 words you must program multiple
file-to-file moves to move different data sets to and from the
block-transfer files.
The first two rungs of the sample program toggle the requests for
block-transfer-reads (BTR) and block-transfer-writes (BTW). When the
BTW is completed, the BTR enables immediately following the BTW
scan. The interlocks shown do not allow a BTR and BTW instruction to
enable at the same time.
When a BTW is successfully completed, its done bit sets. A COP
instruction can move the BTR data file into a storage file.
DN
EN
DN
/
/ /
BTR
EN
Rung 1 Step 2:0
BR001:0 BW001:0
BLOCK XFER READ
Rack 000
Group
1
Module 0
Control Block BR001:0
Data File 1BTD0:0
BT Length 5
Continuous NO
BT Timeout 4
ER
ER
BTW
BLOCK XFER WRITE
Rack
000
Group 1
Module 0
Control Block BW001:0
Data File
1BDT1:0
BT Length 5
Continuous NO
BT Timeout 4
Rung 1 Step 2:1
BR001:0 BW001:0
Rung 1 Step 2:2
[END OF FILE]
1
2
3
EN EN
EN EN
Editing and
Debugging
6
G
Edit a Program Line
G
Delete a Program Line
G
Renumber a Program
G
Debug a Program
PLC-5/250

Family Processors
Ladder Logic
What’s Next?