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  • Library:
  • ONS block


The ONS block implements the ONS instruction. The block makes the remainder of the rung true every time the rung-condition-in transitions from false to true.



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Controls the execution of the block. EnableIn reflects the rung state preceding the block. If the rung state preceding the block is false, EnableIn is false, the block does not execute and the outputs are not updated.


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By default, EnableOut follows the state of EnableIn. If the EnableIn input to the block is false, the logic implemented by the block is not executed and EnableOut signal is set to false.


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Internal storage bit that retains the rung-condition-in from the last time the instruction was executed. Specified in the format of tags. In Ladder Diagrams, tags (variables) are used for representing all inputs, outputs, and internal memory with attributes such as Data Type, Initial Value, and size. To change the attributes of the Operand Tag, open the Program Variables table within the Ladder Diagram Program block.

Programmatic Use

Block Parameter: PLCOperandTag
Type: character vector
Value: character vector
Default: 'SB'

See Also


Introduced in R2019a