Function

Description

Statements

The Structured Text consists of a series of Statements that are separated by semicolons. A statement can extend over several lines; a line end is treated like a space.

A statement is used to calculate and assign a value, to control the flow of commands and to call or exit a POU.

Expressions

An expression is a construct that returns a value after it has been evaluated.

Expressions are composed of Operators and operands. An operand can be a constant, variable, function call or another expression.

Expressions are evaluated by processing the operators according to certain binding rules. The operator with the strongest binding is processed first, followed by the operator with the next strongest binding. This continues until all operators have been processed.

Comments

Comments are marked with parentheses and an asterisk (* Comment *) and are permitted to appear in all places where spaces are allowed. A comment with parentheses and an asterisk can extend over several lines. Nested comments are not possible.