A Converter to RDF is a tool which converts application data from an application-specific format into RDF for use with RDF tools and integration with other data. Converters may be part of a one-time migration effort, or part of a running system which provides a semantic web view of a given application. See also: RDFImportersAndAdapters
RDF Translator is a multi-format conversion tool for structured markup. It provides translations between data formats ranging from RDF/XML to RDFa or Microdata. The service allows for conversions triggered either by URI or by direct text input. Furthermore it comes with a straightforward REST API for developers.
Is the RDF model an entity-relationship mode? Yes and no. It is great as a basis for ER-modelling, but because RDF is used for other things as well, RDF is more general. RDF is a model of entities (nodes) and relationships.