Product details:
Series A3000 Photohelic Pressure Switch/Gage, 2-0-2" cm w.c.3-in-1 Indicating Gage, Lo-limit and Hi-limit Control - 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. 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. 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. - Product Applications - Air Conditioner Systems - Clean Rooms - Fume Exhaust SystemsFeaturesBezel and front cover (with set point knobs and zero adjustment screw) removed to expose Photohelic switch/gage set point mechanism. - Cover is clear polycarbonate plastic. - Gage pointer and light shutter are mounted on helix and balancing counterweight. Shutter passes through slot in optical limit switch to expose phototransistors to integral inf
