Q45D Dissolved Oxygen Transmitter

ATi’s Q45D Transmitter offers Dissolved Oxygen monitoring solutions for applications that require a 2-wire transmitter or battery-operated instrumentation.


Continuous, 2-wire transmitter or battery-operated monitoring

Adaptable to either Optical or Galvanic D.O. sensors, ATi’s Q45D Dissolved Oxygen Monitor is ideal for installations where only analog signals are needed and low power operation is preferred.  ATi’s optical element is designed to last a minimum of 2-years in normal operation, but will more often provide a life of 3-5 years, unless mechanical damage occurs. Optical sensors do not require flow across the sensing element so accurate measurements can be made more accurately in systems with low flows. Unlike some optical sensors, this sensor is not degraded by exposure to sunlight. The Galvanic Dissolved Oxygen sensor uses a rugged 5 mil Teflon membrane to resist mechanical abrasions and tears. The membrane serves as a barrier to allow molecular oxygen to diffuse into the reaction cell where it is reduced, producing a small current which is proportional to oxygen concentration.

For applications requiring AC operation, relay outputs, automatic sensor cleaning, or digital communication, ATi’s Q46D is available. 

Features & specification

  • Loop-powered or battery-operated
  • External 5-17 VDC version for solar power applications
  • Adapts to Optical or Galvanic sensors
  • Submersion or flowcell sensor options
  • Simple air-calibration
  • Large, easy-to-read LCD display
  • Display D.O. in ppm, mg/l, or % saturation
  • Clear menu-driven user interface
  • NEMA 4X (IP-66) enclosure
  • Wall or pipe mounting bracket
  • Built-in PID controller


  • Aeration Systems
  • Fish Farming
  • Wastewater Effluent
  • Rivers & Streams
  • Water Distribution

Key benefits

  • Low powered
  • Optical and galvanic options
  • Analogue signal communications



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