Series 634ES Transmitters sense a single pressure for air, compatible gas or liquid and provide 4-20 mA output signal. Positive pressure can be measured within an accuracy of ±0.5% of span. The Series 634ES uses an isolated piezoresistive pressure sensor to produce a resistance change across a wheatstone bridge. Convenient 2-wire operation simplifies installation. Zero and span adjustments are fully protected inside a rugged die cast aluminum housing with durable gray polyurethane finish. Enclosure is designed to meet NEMA 4X requirements.