DWYER INSTRUMENTS Pressure Switch, NPT 1/8 in Female 0psi to 0.54 psi

Dwyer Instruments A3000 series Photohelic® dual switch and gauge function as versatile, highly repeatable pressure switches combined with a precise pressure gauge. The A3000 measures and controls positive, negative or differential pressures of air and compatible gases. Two phototransistor actuated, DPDT relays are included for low/high limit control. Easy to adjust set point indicators controlled by knobs on the gauge face. Gauge reading is continuous and unaffected by switch operation, even during loss of electrical power.

In typical applications, these switch/gauges controls between high and low-pressure set points. When pressure changes, reaching the set point pressure, the infrared light to the limiting phototransistor is cut off. The resulting phototransistor signal is electronically amplified to actuate its DPDT slave relay and switching occurs.