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Plc-5 programming – Rockwell Automation 1794-IT8,D17946.5.7 Thermocouple/Millivolt Input Module User Manual

Page 25

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3–3

Module Programming

Publication 1794-6.5.7

PLC-5 Programming

The PLC-5 program is very similar to the PLC-3 program with the
following exceptions:

1.

Block transfer enable bits are used instead of done bits as the
conditions on each rung.

2.

Separate block transfer control files are used for the block
transfer instructions.

Figure 3.2
PLC-5 Family Sample Program Structure

BTR Enable Bit

EN

DN

BTW Enable Bit

1

2

ER

EN

DN

ER

BTR

BLOCK TRANSFER READ

RACK:
GROUP:
MODULE:

DATA FILE:
LENGTH:
CONTINUOUS:

N

BTW

BLOCK TRANSFER WRITE

RACK:

GROUP:
MODULE:

LENGTH:
CONTINUOUS:

N

2
1
0

N13:0

11

2

1
0

3

Program Action

CONTROL:

N12:0

DATA FILE:

N13:20

CONTROL:

N12:5

N12:5

15

N12:0

15

Thereafter, the program continuously per-
forms read block transfers.

Pushbutton

The pushbutton allows the user to
manually request a block transfer write.

N13:10

03

Power-up Bit

At power-up in RUN mode, or when the
processor is switched from PROG to RUN,
the user program enables a block transfer
read. Then it initiates a block transfer write
to configure the module.