Rockwell Automation 1791-XXXX ANALOG BLOCK I/O - Manual (Page 52)

Programming Your Analog Module
Chapter 6
6-2
Block transfer instructions with the PLC-3 processor use one binary file in
a data table section for module location and other related data. This is the
block transfer control file. The block transfer data file stores data that you
want transferred to the module (when programming a block transfer write)
or from the module (when programming a block transfer read). The
address of the block transfer data files are stored in the block transfer
control file.
The programming terminal prompts you to create a control file when a
block transfer instruction is being programmed. The same block transfer
control file is used for both the read and write instructions for your
module. A different block transfer control file is required for every
module.
A sample program segment with block transfer instructions is shown in
Figure 6.1, and described below.
Figure 6.1
PLCĆ3 Family Sample Program Structure
EN
BTR
BLOCK XFER READ
RACK:
GROUP:
MODULE:
DATA:
XXX
X
X = XXXX
XXXX:XXXX
LENGTH:
CNTL:
00
XXXX:XXXX
EN
BTW
BLOCK XFER WRITE
RACK:
GROUP:
MODULE:
DATA:
XXX
X
X = XXXX
XXXX:XXXX
DN
LENGTH:
CNTL: 00
XXXX:XXXX
Block Transfer
Read Done Bit
ER
Enable
Done
Error
12
15
13
Enable
Done
Error
02
05
03
Block Transfer
Write Done Bit
1
2
DN
ER
At powerĆup, the user program examines the BTR
done bit in the block transfer read file, initiates a
write block transfer to configure the module, and
then does consecutive read and write block
transfers continuously.
Program Action
PLCĆ3 Program Example