As part of their ongoing development of a wide range of control valves, positioners and accessories, Samson Controls now offers a range of electro pneumatic positioners. These include their Type 3730-3 model, which has been enhanced and incorporates an ESD function to enable partial stroke tests to be carried out, without disrupting the process line. The positioner can be mounted on the valve in addition to the solenoid valve, or to replace it and enables the valve to be moved precisely to follow the set point within the valve’s working range. The partial stroke test is completely integrated into the positioner to detect a sticking valve, caused for example, by corrosion. Test schedules are flexible and can be prolonged if necessary to suit specific application requirements, while test validation can be performed simply by using the corresponding instrumentation and initiating it over a commonly available SIS logic solver.