Spirax Sarco”s SP400 and SP500 positioners consume approximately 1 percent of the air of a traditional electropneumatic positioner and have low impedance. Spirax Sarco has responded to the market need for a simple, easy-to-use digital smart positioner with the new SP400. The SP400 has a very simple menu system and can perform an auto-stroke calibration at the press of a single button, resulting in reduced commissioning time. For those users who require more functionality, the SP500 is a full-featured smart digital positioner with optional retransmission of valve position; software switches, ability to use a separate 24 Vdc power supply and communications protocols as well as diagnostics.