Plcć3 programming – Rockwell Automation 1771-IFE , D17716.5.90 USER MNL. ANALOG INPUT Module User Manual

Page 27

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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

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