(* main.st *)
FUNCTION_BLOCK Counter
VAR_INPUT
    inc : BOOL;
END_VAR
VAR_OUTPUT
    q : INT;
END_VAR
VAR
    count : INT;
END_VAR
    IF inc THEN
        count := count + 1;
    END_IF
    q := count;
END_FUNCTION_BLOCK

PROGRAM MAIN
VAR
    c1 : Counter;
    c2 : Counter;
END_VAR
    c1(inc := TRUE);
    c2(inc := TRUE);
    c2(inc := TRUE);
    a := c1.q * 100 + c2.q;
END_PROGRAM