Series A3000 Photohelic® Pressure Switch/ Gage

The SERIES A3000 Photohelic® Switch/ Gages function as versatile, highly repeatable pressure switches combined with a precise pressure gage employing the time-proven Magnehelic® gage design.The Photohelic® switch/ gage measures and controls positive, negative or differential pressures of air and compatible gases. Standard models are rated to 25 psig ( 1.7 bar) with options to 35 ( 2.4) or 80 ( 5.5 bar) psig. Two phototransistor actuated, DPDT relays are included for low/ high limit control. Easy to adjust set point indicators are controlled by knobs located on the gage face. Individual set point deadband is one pointer width - less than 1% of full scale. Set points can be interlocked to provide variable deadband - ideal for control of fans, dampers, etc. Gage reading is continuous and unaffected by switch operation, even during loss of electrical power. Choose from full scale pressure ranges from a low 0-.25 in ( 0-6 mm) w.c. up to 30 psi ( 21 bar) ; single positive pressure to 6000 psig ( 413 bar) . Photohelic Sensing - How It Works In typical applications, these Dwyer switch/ gages control between high and low pressure set points. When pressure changes, reaching either set point pressure, the infrared light to the limiting phototransistor is cut off by the helix-driven light shutter. The resulting phototransistor signal is electronically amplified to actuate its DPDT slave relay and switching occurs. Dead band between make and break is 1% of full scale or less - just enough to assure positive, chatter-free operation. Relay-Transformer Features A plastic housing protects all electronic components. Solid-state and integrated circuit electronics are on glass-epoxy printed circuit boards and self-extinguishing terminal boards. Please see SERIES AT3A3000 for ATEX approved. Product Applications Air Conditioner SystemsClean RoomsFume Exhaust Systems