P2040¶

Code: P2040
Message: Real literal is outside the range the real type can represent

This error occurs when a real literal names a value too large in magnitude for its type to represent.

A real literal’s type is the type it is used as. REAL holds values up to about 3.4E38 in magnitude, and LREAL up to about 1.8E308. A value beyond that range has no finite number to be stored as, so the compiler reports it rather than storing infinity in place of the number the program wrote.

Example¶

The following code will generate error P2040:

Try it

Source

PROGRAM main
    VAR
        limit : REAL;
    END_VAR
    limit := 1.0E300;  (* Error: beyond REAL *)
END_PROGRAM

To fix this error, use a value the type can hold, or declare a type wide enough for the value you want:

Try it

Source

PROGRAM main
    VAR
        limit : LREAL;
    END_VAR
    limit := 1.0E300;
END_PROGRAM

The same applies to a variable’s initial value, an element of an array or structure initializer, the default of a structure field or type declaration, an argument passed to a REAL parameter, an operand of an operator that computes at REAL, and a value the compiler computes from constants, such as 1.0E30 * 1.0E30.

No real type holds a value such as 1.0E400, so it is reported wherever it is written.

A prefixed literal states its own type¶

A literal with the REAL# or LREAL# prefix names its type, and is held to that type’s range wherever it is written:

Try it

Source

PROGRAM main
    VAR
        limit : LREAL := REAL#1.0E40;  (* Error: beyond REAL *)
    END_VAR
END_PROGRAM

Drop the prefix, or write LREAL#, to keep the value.

Think IronPLC is wrong about this?

If you believe this diagnostic is incorrect, open an issue on GitHub with a small sample that demonstrates the problem.