1756-PM003H-EN-E, SFC and ST Programming Languages ...

10-6 Program Control Instructions (JSR, RET, SBR)
The following diagram illustrates how the instructions operate.
Calling Routine
Subroutine
SBR
1. If the JSR instruction has an input
parameter, enter an SBR instruction.
JSR
1. If you want to copy data to a tag in
the subroutine, enter an input
parameter.
2. If you want to copy a result of the
subroutine to a tag in this routine,
enter a return parameter.
3. Enter as many input and return
parameters as you need.
JSR
SBR
RET
RET
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2. Place the SBR instruction as the first
instruction in the routine.
3. For each input parameter in the JSR
instruction, enter the tag into which
you want to copy the data.
RET
1. If the JSR instruction has a return parameter, enter an RET
instruction.
2. Place the RET instruction as the last instruction in the routine.
3. For each return parameter in the JSR instruction, enter a return
parameter to send to the JSR instruction.
4. In a ladder routine, place additional RET instructions to exit the
subroutine based on different input conditions, if required.
(Function block routines only permit one RET instruction.)
There are no restrictions, other than controller memory, on the
number of nested routines you can have or the number of parameters
you pass or return.
level 1
subroutine action_1
level 2
subroutine action_2
level 3
subroutine action_3
main routine
action_1
SBR
SBR
SBR
JSR
action_2
action_3
JSR
JSR
RET
RET
RET
Publication 1756-PM003H-EN-E (excerpt from 1756-RM003H-EN-P) - August 2005