674
Subroutines Section 3-18
Example 3: Nested Subroutines
When CIO 0.00 is ON in the following example, subroutine 1 is executed. If
CIO 0.01 is ON, subroutine 2 is executed from within subroutine 1 and pro-
gram execution returns to the next instruction after SBS(091) 2 when subrou-
tine 2 is completed. Execution of subroutine 1 continues and program
execution returns to the next instruction after SBS(091) 1 when subroutine 1
is completed.
3-18-2 MACRO: MCRO(099)
Purpose Calls the subroutine with the specified subroutine number and executes that
program using the input parameters in S to S+3 and the output parameters in
D to D+3.
Ladder Symbol
1
5
2
4
3
CIO 0.00 ON
CIO 0.01 ON
1
2
2
1
A→S1-1→S2→S1-2→B
A→S1-1→S1-2→B
A→B
A→B
0.00
0.00
0.01
0.01
Subroutine 1
Subroutine 2
Order of execution
MCRO(099)
N
S
D
N: Subroutine number
S: First input parameter word
D: First output parameter word
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