PIR technology senses occupancy by detecting the difference between heat emitted from the human body in motion and the background space. Relying on a clear line-of sight view, passive infrared sensors make 100% coverage cut off possible. These sensors utilize a unique fresnel lens which divides the coverage area into zone, enhancing detection of small movement. Using the doppler principle, ultrasonic sensors work by bouncing ultrasonic sound waves off objects in an area and measuring the time it takes for the waves to return. Movement by a person in the area causes the sound waves to return at a changed frequency, resulting in a doppler shift and occupancy detection.

WattStopper®, DT-355, Ceiling Mount Occupancy Sensor, Dual Technology Line Voltage Low Profile, Series: DT Series, 24 VAC/VDC, 0 to 1500 W Power, Passive Infrared/Ultrasonic Sensor, 1000 sq-ft Coverage, 360 deg Viewing, 5 to 30 min Time Delay, LED/Tungsten Lamp, 40 kHz Response, Flying Lead Connection, Automatic On/Automatic Off Control Output, 35 deg C, Plastic, White, 4.5 in Dia x 1.02 in D Dimensions

• https://externalassets.unilogcorp.com/ASSETS/DOCUMENTS/ITEMS/EN/WattStopper_DT355_Catalog.pdf https://www.iesbuy.com//ASSETS/DOCUMENTS/ITEMS/EN/https://externalassets.unilogcorp.com/ASSETS/DOCUMENTS/ITEMS/EN/WattStopper_DT355_Catalog.pdf
• https://externalassets.unilogcorp.com/ASSETS/DOCUMENTS/ITEMS/EN/WattStopper_DT355_Installation_Manual.pdf https://www.iesbuy.com//ASSETS/DOCUMENTS/ITEMS/EN/https://externalassets.unilogcorp.com/ASSETS/DOCUMENTS/ITEMS/EN/WattStopper_DT355_Installation_Manual.pdf
• https://externalassets.unilogcorp.com/ASSETS/DOCUMENTS/ITEMS/EN/WattStopper_DT355_Line_Drawing.pdf https://www.iesbuy.com//ASSETS/DOCUMENTS/ITEMS/EN/https://externalassets.unilogcorp.com/ASSETS/DOCUMENTS/ITEMS/EN/WattStopper_DT355_Line_Drawing.pdf
• https://externalassets.unilogcorp.com/ASSETS/DOCUMENTS/ITEMS/EN/WattStopper_DT355_Specification_Sheet.pdf https://www.iesbuy.com//ASSETS/DOCUMENTS/ITEMS/EN/https://externalassets.unilogcorp.com/ASSETS/DOCUMENTS/ITEMS/EN/WattStopper_DT355_Specification_Sheet.pdf

• Operates at 120, 230 (single phase), 277 or 347 VAC, 50/60 Hz
• Terminal wiring for quick and easy installation
• Walk-through mode increases savings potential
• Architecturally appealing low profile appearance
• Ultrasonic diffusers give more comprehensive coverage