Ceiling Mount Occupancy Sensor, Ultrasonic, Low Voltage

Model: OAC-U

The MicroSet Ultrasonic Low Voltage Occupancy Sensing Ceiling Sensor is a motion sensing lighting control that is used for energy savings and convenience.

The ultrasonic sensor uses the Doppler principle. It produces a low intensity, inaudible sound and detects changes in sound waves caused by motion, such as walking into the room,  reaching for the telephone, or turning in a chair. They are volumetric in nature and therefore not line-of-sight dependant. Since they fill the space with these sound waves, they are  excellent in bathrooms with stalls, enclosed hallways, or other oddly shaped rooms. In addition, they are much more sensitive to smaller motions. The sensor includes self-adaptive technology that continuously self-adjusts sensitivity and Time Delay in real-time, maximizing the potential energy savings that are available in the particular application. In Automatic On Mode, the lights turn ON when a person enters the room. In Manual On Mode (-R model only), the lights are turned ON by activating a momentary switch (model # GMDS-*) that is connected to the sensor. The MicroSet Ultrasonic Low Voltage Ceiling Sensor has an ambient light level sensor. When enabled, the daylighting feature (-R models only) prevents lights from turning ON when the room is adequately illuminated by natural light.


Ceiling Mount Occupancy Sensor, Ultrasonic, Low Voltage



  • Ultrasonic (US)

Power Requirements:

  • Input:
    • 10-30 VDC from Greengate Switchpack or system
    • Maximum current needed is 25mA per sensor
  • Output:
    • Open collector output to switch up to ten Greengate Switchpacks
    • BAS with Isolated Form C Relay in (-R) model
    • Isolated Form C Relay Ratings: 1A 30 VDC/VAC

Time Delays:

  • Self-adjustable, 15 seconds/test (10 minutes Auto), or Selectable 5, 15, 30 minutes, or Zero Time Delay


  • 500, 1000, and 2000 sq. ft. (56 ft. x 16 ft. corridor)

Light Level Sensing (-R Models):

  • 0 to 300 foot-candles

Operating Environment:

  • Temperature: 32°F - 104°F (0°C - 40°C)
  • Relative humidity: 20% to 90%, non-condensing
  • For indoor use only


  • Durable, injection molded housing. Polycarbonate resin complies with UL 94V-0
  • Size 1.42”H x 4.5”W (36.068mm x 114.3mm)
  • Mounting Mounts directly to ceiling tile, to a 4” square box and round mud ring or to 4” octagon box

LED Indicators:

  • Green LED for Ultrasonic detection


  • FCC Compliant
  • cULus Listed
  • RoHS Compliant
  • MicroSet self-adjusting time delay and sensitivity
  • Optional built-in light level sensor  
  • Optional BAS/HVAC isolated relay
  • Products tested to NEMA WD 7 - 2011 Occupancy Motion Sensors Standard
  • Selectable Walk-Through Mode 
  • Dual Relay control