Allen-Bradley LOGIX 5000 Reference Manual page 461

Equipment Phase Instructions
Guideline
Use the PSC instruction in each phase state routine that is added to an equipment phase.
Remember that the PSC instruction does not stop the current scan of a routine.
Do not use a PSC instruction in a prestate routine.
Structured Text
None
Enter the parentheses ( ) after the instruction mnemonic, even though there are no
operands.
Guidelines for using the PSC Instruction
Affects Math Status Flags
No
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
Chapter 7
Details
Without a PSC instruction, the
equipment phase remains in the state
and does not go to the next state.
• Place the PSC instruction as the
last step in the phase state routine.
• When the state is done (complete),
execute the PSC instruction.
In the holding state routine, use the
PSC instruction to let the equipment
phase go to the Held state
When the PSC instruction executes,
the controller scans the rest of the
routine and then transitions the
equipment phase to the next state.
The PSC instruction does not
terminate the execution of the
routine.
Use the PSC instruction only to signal
the transition from one state to
another.
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