Equipment Sequence Clear Failure (SCLF)

This instruction applies to the
Logix Designer
 5580 P-controllers. The
Logix Designer
 5580 P-controllers also support controller redundancy.
TIP:
When using this instruction with
ControlLogix
 redundancy system, outputs controlled by this instruction may not be bumpless during redundancy switchover, if the instruction and sequence program are not scheduled in the highest priority task.
WARNING:
When using redundancy with an
Equipment Sequence
, sequence execution may not be as expected after switchover if the phase and sequence are not scheduled on the same task.
Use the
Equipment Sequence
 Clear Failure (SCLF) instruction to clear the failure code of an
Equipment Sequence
. Keep this in mind when using the SCLF instruction.
  • A CLR instruction, MOV instruction, or assignment does not change the failure code of an
    Equipment Sequence
    .
  • The
    Equipment Sequence
     cannot have other owners when you use the SCLF instruction. The SCLF instruction does not clear the failure code if the
    Logix Designer
     application,
    FactoryTalk Batch
     software, or another program owns the
    Equipment Sequence
    .
  • An
    Equipment Sequence
     refuses a RESUME command until it is cleared of failures.
This is a transitional instruction. Follow these steps when using it:
  • In ladder logic, insert an instruction to toggle the rung-condition-in from false to true each time the instruction should execute.
  • In a Structured Text routine, insert a condition for the instruction to cause it to execute only on a transition.
Available Languages
The SCLF instruction is available in these languages.
  • Ladder diagram
    L5K_SILC_SCLFLadderExampleSmall
  • Structured text: SCLF(SequenceName)
Supported Operands
The SCLF instruction uses these operands.
Operand
Type
Format
Description
Sequence Name
Sequence
name of the
Equipment Sequence
Equipment Sequence
 for which you want to clear a failure code.
Result
DINT
Immediate tag
For an instruction to return a success or failure code, enter a DINT tag where the result code is stored. Otherwise, enter
0
.
Arithmetic status flags and fault conditions
Arithmetic status flags are not affected by the SCLF instruction. The SCLF instruction cannot trigger a fault, so there are no fault conditions for this instruction.
Instruction execution
The table describes the execution steps for SCLF instructions.
Condition
ladder_icon Ladder Diagram Action
st_icon 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 or a structured text construct that includes a condition, such as if, then, or else.
Instruction execution
The instruction clears the value of the failure code for the specified
Equipment Sequence
.
The instruction clears the value of the failure code for the specified
Equipment Sequence
.
Postscan
The rung-condition-out is set to false.
No action taken.
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