If the string representation of a certain field is equal to the specified value, then the value is set the null (empty). You can add all fields from the input stream(s) using Get Fields.
Note: When a conversion for non-string fields is needed (like Date or Number data types) the conversion mask is taken from the existing conversion mask of the meta data in the stream of this field and not the default conversion mask. This has been implemented in PDI 7.1 by PDI-14101. Before, it took the default conversion mask. When upgrading to 7.1, you need to make sure that the conversion mask fits to the meta data in the stream and does not rely on the default conversion mask.
All fields of this step support metadata injection. You can use this step with ETL Metadata Injection to pass metadata to your transformation at runtime.