Nynas, a Sweden-based specialised oil producer, has selected PlantWeb(R) field-based architecture with Foundation(TM) fieldbus digital communications from Emerson Process Management to automate critical control loops at its bitumen refinery in Sweden. The architecture was considered ideal for the project because of its implementation of fault tolerant redundancy with the fieldbus technology. Baumann 24000S series control valves, fitted with Fieldvue® Digital Valve Controllers, were selected to control the steam flow used to maintain the tanks and process lines at the right temperature. These valves are installed on the same Foundation fieldbus segment as the relevant temperature transmitters, which are the dual sensor Rosemount type 3244MV. The Hot Backup(TM) feature in this transmitter allows connection of two independent temperature-monitoring elements. If the first, primary temperature sensor element should be detected as having failed, there is a seamless transfer of the 3244MV transmitter output to follow the second element.