Allen-Bradley PLC-2/30

Jump Instructions and
Subroutine Programming
Chapter 11
116
Figure 11.5
Multiple
JUMPS to LABEL in Subroutine Area and Multiple Return Paths
to Main Program
Main Program
( JSR )
03
||
| / ||| ( JSR )
03
||
||
||
( JSR )
03
||
|| ()
|| ()
|| ()
||LBL ()
03
( RET )
(Subroutine)
Subroutine Area
A
B
C
a
b
c
The Label instruction shown in Figure 11.6 is the target destination for
both the Jump and Jump to Subroutine instructions. Labels are assigned
octal identification numbers from 00-77. The label identification number
must be the same as that of the Jump and/or Jump to Subroutine instruction
with which it is used. A label instruction can be defined only once,
meaning that a label with a given identification number can appear in only
one location. However, a Label instruction can be the target of jumps from
more than one location.
Figure 11.6
LABEL
Format
LBL ()
XX
XX = Octal Identification Number
||
11.2
Label Instruction
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