Compiler Warning C0533

Message: The default value for a VAR_OUTPUT is not used in abstract or interface methods

Possible error cause: In a method of an abstract POU, an initial value is assigned to a VAR_OUTPUT.

In the case of interface methods and abstract methods, the initial value at the output has no effect, in contrast to initial values at the input.

Error correction: Remove the initial value from the affected VAR_OUTPUT.

Example of the warning:

FUNCTION_BLOCK ABSTRACT POU

METHOD METH: BOOL
VAR_INPUT
      iPar : INT;
      xPar : BOOL;
END_VAR
VAR_OUTPUT
      iOut : INT;
      xOut : BOOL := TRUE;
END_VAR

The declaration of the variable xOut produces the following warning.

Message:

C0533: The default value for a VAR_OUTPUT is not used in abstract or interface methods