An electro-pneumatic converter device with modular components and with supporting housing structure enabling the device to be readily convertible from a current to pressure positioner to a current to pressure transducer. A valve positioner with an enclosure having a housing, a modular base, and a separable...http://www.google.com/patents/US5439021?utm_source=gb-gplus-sharePatent US5439021 - Electro-pneumatic converter
