Rockwell Automation 1772-LS_LSP,D17726.8.6 PROG/OPER MANUAL-MINI PLC-2/05 - Manual (Page 215)

Programming Techniques
Chapter 18
18-7
Figure 18.7
Recording Temperature Values Every 5 Seconds
030
15
030
1.0
15
030 02
JSR
TON
PR 005
AC 000
06
LBL
100
200 203
X
900 009
201
G G
202
X
000
900
203 206
:
005
204
G G
205
:
180. 000
180
205 210
+
032
207
G G
212
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 timing.
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: Make allowances for conditions which could be
created by the use of the Jump to Subroutine instruction.
Subroutine program rungs are not scanned by the processor
unless initiated by the Jump to Subroutine is initiated by the
main program. 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.