Rockwell Automation 1772-L8_LW_LWP_LX_LXP,D17726.5.8 User Manual User Manual

Page 398

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Programming Technique

Chapter 25

25-8

Figure 25.7

Recording Temperature Values Every 5 Seconds

200

100

X

202

000

G

201

009

G

X

203

900

203

900

:

205

180.000

G

204

005

G

206

:

205

180

212

G

207

032

G

210

+

030

15

TON

1.0

030

PR 005

AC 000

030

15

JSR

02

LBL

06

RET

SUBROUTINE AREA

Here is an explanation of each rung:

Rung 1:

When rung 1 is true, the timer (this is an example of a free
running timer) starts.

Rung 2:

The JSR instruction jumps to the subroutine area label
instruction when the timer’s accumulated value reaches
5 seconds.

Rungs 3-5: Converts Celsius temperature to Fahrenheit temperature

exactly as in application one.

Rung 6:

The Return instruction signals the processor to return to
the main program area.

ATTENTION: You should make allowances for conditions
which could be created by the use of the Jump To Subroutine
instruction. The processor does not scan the subroutine
program unless initiated by a Jump To Subroutine in the main
program. Timers and counters within these rungs cease to
function. You should reprogram critical rungs in the main
program area.

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