Initial Values¶

Variables can be assigned initial values in their declaration using the := operator.

IEC 61131-3	Section 2.4.3
Support	Supported

Syntax¶

variable_name : type_name := initial_value ;

The initial value must be a constant expression compatible with the variable’s type.

Example¶

Try it

Source

PROGRAM main
    VAR
        counter : INT := 0;
        active : BOOL := TRUE;
        scale : REAL := 1.5;
    END_VAR

    counter := counter + 1;
END_PROGRAM

If no initial value is specified, the variable is initialized to the default value of its type (typically zero or empty).

See Also¶

Variable Declarations — variable declaration syntax
Data Types — default values for each type