An expression is a construct that returns a value following its evaluation.
Expressions consist of operators and operands. In ⮫ Extended Structured Text (ExST), ⮫ Extended Structured Text (ExST), ⮫ Extended Structured Text (ExST), you can also use assignments as expressions. An operand can be a constant, variable, function call, or another expression.
Special ST expressions are also:
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Access to
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Elements of array variables
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Components of a structure variable
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Variables of a function block instance or a program
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Method call
Examples
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Constant, literal |
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Variable |
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Function call |
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Expression |
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In ExST: Assignment |