Rockwell Automation Publication 1756-RM006K-EN-P - November 2018 473
Execution
Ladder Diagram
Condition Action Taken
Prescan The rung-condition-out is set to false.
Rung-condition-in is false The rung-condition-out is set to false.
Rung-condition-in is true The instruction executes.
The rung-condition-out is set to true.
Scan of structured text No action taken
Instruction execution The instruction tries to take ownership of the specified Equipment
Sequence.
Postscan The rung-condition-out is set to false.
Structured Text
Condition Action Taken
Prescan No action taken.
Rung-condition-in is false No action taken.
Rung-condition-in is true No action taken.
Scan of structured text In structured text, instructions execute each time they are scanned. To
limit the scan of an instruction, use a qualifier of an SFC action or a
structured text construct that includes a condition, such as if, then, or else
Instruction execution The instruction tries to take ownership of the specified Equipment
Sequence.
Postscan No action taken.
See also
Result codes for SCLF instructions on page 482
SDET instruction examples on page 487
Equipment Sequence Instructions on page 465
Use the Equipment Sequence command (SCMD) instruction to change the state
of an Equipment Sequence. The SCMD instruction can send the following
commands to an Equipment Sequence: START, RESTART, HOLD, STOP,
ABORT, and RESET. The program must attach to an Equipment Sequence
before the SCMD instruction can run. Use the SATT instruction to attach to an
Equipment Sequence.
Like the SCMD instruction, the Equipment Sequence Override instruction
(SOVR) also changes the state of an Equipment Sequence, but it changes the state
command (SCMD)
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