Detach from Equipment Sequence (SDET)

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 Detach from
Equipment Sequence
 (SDET) instruction to relinquish ownership of an
Equipment Sequence
. After a program executes an SDET instruction, the program no longer owns the
Equipment Sequence
. The
Equipment Sequence
 is then available for ownership by another program or by
FactoryTalk Batch
 software. Use the SDET instruction only if the program previously took ownership of an
Equipment Sequence
 through an Attach to
Equipment Sequence
 (SATT) instruction.
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 SDET instruction is available in these languages.
  • Ladder diagram
    L5K_SILC_SDETLadderExampleSmall
  • Structured text: SDET(SequenceName)
Supported Operands
The SDET instruction uses this operand.
Operand
Type
Format
Description
Sequence Name
Sequence
name of the
Equipment Sequence
Equipment Sequence
 for which you want to relinquish ownership.
Arithmetic status flags and fault conditions
Arithmetic status flags are not affected by the SDET instruction. The SDET instruction cannot trigger a fault, so there are no fault conditions for this instruction.
Instruction execution
The table describes the execution steps for SDET 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 relinquishes ownership of the specified
Equipment Sequence
.
The instruction relinquishes ownership of the specified
Equipment Sequence
.
Postscan
The rung-condition-out is set to false.
No action taken.
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