Attention

IronPLC supports IEC 61131-3 Structured Text excluding I/O mapping.

P4013

Code

P4013

Message

POU declaration name is duplicated

This error occurs when a POU (Program Organization Unit) declaration name is duplicated within the same scope.

Example

The following code will generate error P4013:

FUNCTION_BLOCK MyFunction
END_FUNCTION_BLOCK

FUNCTION_BLOCK MyFunction  (* Error: Duplicate POU name *)
END_FUNCTION_BLOCK

The function block MyFunction is declared twice, which is not allowed.

To fix this error, ensure all POU names are unique within their scope:

FUNCTION_BLOCK MyFunction1
END_FUNCTION_BLOCK

FUNCTION_BLOCK MyFunction2  (* Correct: Different name *)
END_FUNCTION_BLOCK