Samson Controls has launched its Series 3731 explosion-proof valve positioners. These positioners are housed in an enclosure which, even if an explosive atmosphere forms inside the enclosure and ignites, the enclosure will withstand the explosion and will also prevent the passage of flames out to the explosive surroundings. These intrinsically safe positioners can be configured on-site, or by using HART communication. A single rotary pushbutton, which is usable in hazardous areas, is used for start-up; turn to select parameters and then push to activate them. The design of the enclosure with its separate terminal compartment, allows direct cable entry or connection without spark barriers for cable conduit systems. A liquid crystal display ensures that relevant data is visible at a glance and regardless of the valves mounting position, data is never displayed upside down because the display can be rotated by 180 at the push of a button. The analog control helps the positioner achieve positioning accuracy, which allows the microprocessor to concentrate on other tasks. The additional option of fully integrating expert valve diagnostics into the postioner provides all the necessary information for predictive maintenance.