Allen-Bradley LOGIX 5000 Reference Manual page 445

Equipment Phase Instructions
Structured Text
The operands are the same as those for the Ladder Diagram PFL instruction.
Guidelines for using the PFL Instruction
Guideline Details
Put the PFL The PFL instruction sets the failure code for the equipment phase in which the instruction is put. There
instruction in the is no operand to identify a specific equipment phase.
equipment
Typically, put the PFL instruction in a prestate routine for the equipment phase.
phase.
• The controller always scans the prestate routine, even when an equipment phase is in the idle
state.
• The controller scans the prestate routine before each scan of a state.
Number
Use the progress routine to continuously monitor the health of an equipment phase as it progresses
through its states.
Prioritize failure The PFL instruction sets the failure code only to a value greater than its current value.
codes.
• For example, if a PFL instruction sets the failure code = 102, another PFL instruction can only set
the failure code > 102.
• Make sure to assign higher values to exceptions that require higher priority in their handling.
Otherwise, a lower priority exception may overwrite a more critical exception.
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
Description
Prestate routine
Current state routine
Chapter 7
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