Omron SYSMAC CS Series, Reference Manual, Page: 853 / 1405

813
Subroutines
Section 3-19
Note A subroutine can be called more than once in a program.
Subroutines and
Differentiation Observe the following precautions when using differentiated instructions
(DIFU(013), DIFU(014), or up/down differentiated instructions) in subroutines.
The operation of differentiated instructions in a subroutine is unpredictable if a
subroutine is executed more than once in the same cycle. In the following
example, subroutine 0001 is executed when CIO 000000 is ON and
CIO 000100 is turned ON by DIFU(013) when CIO 000001 has gone from
OFF to ON. If CIO 000001 is ON in the same cycle, subroutine 0001 will be
executed again but this time DIFU(013) will turn CIO 000100 OFF without
checking the status of CIO 000001.
Execution condition ON
Main program
Execution condition ON
Subroutine
program n
Two-level
nesting
Subroutine
program m
Program end
1
3
2
4
5
1
1
1
Subroutine
0001
The subroutine is
executed again.