Rockwell Automation 1794-Lxxxx PhaseManager - Manual (Page 60)

60 Publication LOGIX-UM001B-EN-P - April 2010
Appendix A Equipment Phase Instructions (PSC, PCMD, POVR, PFL, PCLF, PXRQ, PRNP, PPD, PATT, PDET)
Guidelines for Using the PSC Instruction
Arithmetic Status Flags: not affected
Fault Conditions: none
Execution:
Guideline Details
Use the PSC instruction in each
phase state routine that you add to
an equipment phase. 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 your phase state routine.
• When the state is done (complete), execute the PSC instruction.
Remember that the PSC instruction
does not stop the current scan of a
routine. 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 termiN/Ate
the execution of the routine.
Do not use a PSC instruction in a
prestate routine. Use the PSC instruction only to signal the transition from one state to another.
In the holding state routine, use
the PSC instruction to let the
equipment phase go to the Held
state.
Condition Relay Ladder Action Structured Text Action
prescan The rung-condition-out is set to false. No action taken.
rung-condition-in is false The rung-condition-out is set to false. N/A
rung-condition-in is true The instruction executes.
The rung-condition-out is set to true.
N/A
scan of structured text N/A In structured text, instructions execute each time
they are scanned. To limit the scan of an instruction,
use a qualifier of an SFC action and/or a structured
text construct.
instruction execution The instruction signals that the state is complete. The instruction signals that the state is complete.
postscan The rung-condition-out is set to false. No action taken.