Function Block - Allen-Bradley Logix5000 Reference Manual

Chapter 11 Program Control Instructions (JMP, LBL, JSR, RET, SBR, JXR, TND, MCR, UID, UIE, AFI, NOP, EOT, SFP, SFR, EVENT)
Condition
Instruction execution.
Input Parameters
Logic execution begins in routine
identified by JSR.
RET Instruction
End Of Subroutine
Rung-condition-out is set to false.
Continue executing routine.
Postscan
Condition
Prescan
Instruction first scan
Instruction first run
Normal execution
Postscan
458
Relay Ladder Action
Yes
No
Yes
No
Yes
No
Rung-condition-out is set to true.
Logic execution returns to JSR.
Same action as prescan described above.

Function Block

Action
No action taken.
No action taken.
No action taken.
1. If the routine contains an SBR instruction, the controller first executes the SBR instruction.
2. The controller latches all data values in IREFs.
3. The controller executes the other function blocks in the order that is determined by their wiring. This includes
other JSR instructions.
4. The controller writes outputs in OREFs.
5. If the routine contains an RET instruction, the controller executes the RET instruction last.
The subroutine is called.
If the routine is an SFC routine, the routine in initialized the same as it is during prescan.
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Structured Text Action
JSR copies input parameters to
appropriate SBR tags.
Yes
Return Parameters
No
End
Same action as prescan described above.
RET copies return parameters to
appropriate JSR tags.