Manual
74 Publication LOGIX-UM001B-EN-P - April 2010
Appendix A Equipment Phase Instructions (PSC, PCMD, POVR, PFL, PCLF, PXRQ, PRNP, PPD, PATT, PDET)
Arithmetic Status Flags: not affected
Fault Conditions: none
Execution:
To clear the failure code, use a PCLF
instruction.
You must use a PCLF instruction to clear the failure code of an equipment phase. Instructions
such as a CLR or MOV won’t change the failure code. See Equipment Phase Clear Failure
(PCLF) instruction on page 76.
Guideline Details
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 sets the value of the failure code for
the equipment phase.
The instruction sets the value of the failure code for
the equipment phase.
postscan The rung-condition-out is set to false. No action taken.