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Configuration Error (PLCN0021): The connected port '...' is not referenced in any program instance.

A port which is assigned in the GDS Port List of the controller cannot be found in any program instance of the project.

Possibly, the port has been renamed in the local POU type. After renaming the port in the local variable grid, it is automatically added to the GDS Port List. However, the origin port remains in the Port List and is still assigned to another port or process datum.
It is also possible that the POU containing the suspected port has been deleted (either a local one or a library POU). This occurs typically after a library update.

In case of an unassigned port, the semantic error SEM1087 is reported instead.

Remedy

  1. Double-click the error message to open the 'GDS Port List' editor of the 'PLCnext' node in the PLANT. The suspected table line is marked.
  2. Make sure that the suspected port is declared in any program type.

    Alternatively, you can remove the assignment of the non existing port and then delete it. (Afterwards assign the port used instead, if required.)

    In case of a missing POU, make sure that the POU is available.