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Rockwell Automation 1747-PT1, D1747NP002 Hand-Held Terminal User Manual

Page 257

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Instructions

Chapter 18
I/O Message and Communication

18–11

Example 2 – Program File 2 of SLC 5/02 Processor

(U)

B3

0

(EN)

(DN)

(ER)

MSG

READ/WRITE MESSAGE
Read/write

WRITE

Target Device

500CPU

Control Block

N10:0

Control Block Length

7

END

0

2

* MSG instruction
status bits:
13 = DN
15 = EN

]/[

N7:0

0

(L)

B3

0

( )

N7:0

1

(RES)

T4:0

(EN)

(DN)

TON

TIMER ON DELAY
Timer

T4:0

Time Base

0.01

Preset

400

Accum

0

Temperature–sensing
Input Device

] [

S:1

15

] [

S:4

6

3

] [

B3

0

(L)

N7:0

0

] [

S:1

15

] [

I:1.0

5

(EN)

(DN)

(ER)

MSG

READ/WRITE MESSAGE
Read/write

READ

Target Device

500CPU

Control Block

N11:0

Control Block Length

7

] [

N10:0

13*

] [

T4:0

DN

] [

N11:0

13*

(U)

B3

0

(RES)

T4:0

(L)

N7:0

0

(U)

N11:0

15*

(U)

N10:0

15*

Operation notes appear on the following page.

4

5

6

7

Bit 1 of the message
word. Used for fan
control.

Bit 0 of the message
word. This is the
interlock bit.

4–second Timer

Write message instruction.
The source and target file
addresses are N7:0
Target node: 3
Message length: 1 word.

Read message instruction.
The destination and target
file addresses are N7:0
Target node: 3
Message length: 1 word.

Latch – This alarm
instruction notifies the
application if the interlock
bit N7:0/0 remains set for
more than 4 seconds.

First Pass Bit

First Pass Bit

1280 ms Clock Bit

Message Write Done
Bit

Message Read Done
Bit

1

(L)

B3

10