458 Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Chapter 11 Program Control Instructions (JMP, LBL, JSR, RET, SBR, JXR, TND, MCR, UID, UIE, AFI, NOP, EOT, SFP, SFR, EVENT)
Function Block
Instruction execution.
Postscan Same action as prescan described above. Same action as prescan described above.
Condition Relay Ladder Action Structured Text Action
Input Parameters
Yes
No
JSR copies input parameters to
appropriate SBR tags.
End
Logic execution begins in routine
identified by JSR.
End Of Subroutine
Yes
No
Rung-condition-out is set to false.
Continue executing routine.
Return Parameters
Yes
No
RET copies return parameters to
appropriate JSR tags.
Rung-condition-out is set to true.
Logic execution returns to JSR.
RET Instruction
Yes
No
Condition Action
Prescan No action taken.
Instruction first scan No action taken.
Instruction first run No action taken.
Normal execution 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.
Postscan The subroutine is called.
If the routine is an SFC routine, the routine in initialized the same as it is during prescan.
To Next Page
Loading...
Need help?
General
