Attention

IronPLC can only run very simple programs. The steps described are accurate but many language features are not yet supported.

PROGRAM

A program is the top-level executable unit in IEC 61131-3. Programs are instantiated within resources and scheduled by tasks.

IEC 61131-3

Section 2.5.3

Support

Supported

Syntax

PROGRAM program_name
    variable_declarations
    statement_list
END_PROGRAM

Example

PROGRAM main
    VAR
        counter : INT := 0;
    END_VAR

    counter := counter + 1;
END_PROGRAM

Programs can contain local variables (VAR), input variables (VAR_INPUT), and output variables (VAR_OUTPUT). Unlike functions, programs retain their variable values between execution cycles.

See Also