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Examine If Open

  • XIO block



XIO is one of the building blocks of a ladder diagram. The XIO block implements the XIO ladder logic instruction. The block examines the operand tag (data bit) for an off condition. If the bit is clear, the rung is enabled. If the bit is set, the rung is disabled.


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Specify the data bits to be tested. Data bits are specified in the format of tags. In Ladder Diagrams, tags (variables) are used to represent 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: 'A'

Version History

Introduced in R2019a

See Also

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