Rockwell Automation 1771-IFE , D17716.5.90 USER MNL. ANALOG INPUT Module - Manual (Page 27)

Module Programming
Chapter 3
3-3
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 your module (when programming a block transfer
write) or from your module (when programming a block transfer read).
The address of the block transfer data files are stored in the block transfer
control file.
The industrial 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 3.2, and described below.
Figure 3.2
PLCĆ3 Family Sample Program Structure
Block Transfer
EN
BLOCK XFER READ
RACK:
GROUP:
MODULE:
DATA:
LENGTH =
CNTL:
XXX
X
X=XXXX
XXXXX=XXXX
X
XXXXX:XXXX
ENABLE
12
DN
DONE
15
Done Bit
Pushbutton
Power-up
Bit
EN
ENABLE
02
ER
ERROR
03
Block Transfer
Write
Done Bit
DN
DONE
05
1
2 BLOCK XFER WRITE
RACK :
GROUP :
MODULE:
DATA:
XXX
X
X = XXXX
XXXXX = XXXX
LENGTH =
CNTL:
X
XXXXX:XXXX
ER
ERROR
13
At powerĆup, the user program examines, the
BTR done bit in the block transfer read file,
initiates a block transfer write to configure the
module, and then does consecutive block
transfer reads continuously. The powerĆup bit
can be examined and used anywhere in the
program.
Rungs 1 and 2
Rungs 1 and 2 are the block transfer read and
write instructions. The BTR done bit in rung 1,
being false, initiates the first read block transfer.
After the first read block transfer, the module
performs a block transfer write and then does
continuous block transfer reads until the
pushbutton is used to request another block
transfer write. After this single block transfer
write is performed, the module returns to
continuous block transfer reads automatically.
Program Action
Read
BTR
BTW
PLCĆ3 Programming