Rockwell Automation 1771-IFE ANALOG INPUT MODULE - Manual (Page 29)

3–3 Module Programming
Publication 1771Ć6.5.115 - February 1999
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 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
10955ĆI
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