Trace Oxygen Transmitters Series 3500/3510 EX

Trace Oxygen Transmitter Series 3500/3510 EX

Trace Oxygen Transmitters Explosion Proof Series 3500/3510 are blind transmitters designed to provide exceptional performance, accuracy, and stability.  Shown here with its explosion-proof enclosure.

The Series 3500 Trace Oxygen Transmitter is a true loop powered (14-32 VDC) trace oxygen transmitter designed to provide accurate and dependable trace oxygen measurements in a variety of background gases.  Measurement ranges available are from 0-10 PPM to 0-20,000 PPM.

The Series 3500 enclosure is made from durable polycarbonate and is rated for NEMA 4 (IP 66) service (may change with the addition of certain optional equipment). Also available in an optional NEMA 7 (explosion proof).

Competitively priced.   


  • Long Life Trace Oxygen Sensor:  Provides up to three times the functional life of most “fuel cell” type sensors. Reliability is dramatically increased while maintenance costs are reduced.
  • Sealed Sensor:  Eliminates handling potassium hydroxide (caustic), a hazardous material or having to frequently “recharge” the electrolyte.
  • CO2 Resistant Sensor:  Optional CO2 resistant sensor is designed to operate with sample gases containing up to 100% CO2. Conventional “fuel cell” type sensors using potassium hydroxide (KOH) electrolyte can be poisoned from CO2.
  • Affordable: Affords savings of up to 30% and more over other manufacturers trace oxygen transmitters.
  • Wide Measurement Range:  Measure from under 1 PPM to as high as 20,000 PPM oxygen.
  • Factory Calibration:  Factory calibration included at no additional charge. Upon request, NIST calibration certificates available.
  • NEMA 4 Enclosure:  NEMA 4 Enclosure (Optional NEMA 7 explosion proof enclosure available)

High Performance Trace Oxygen Sensor

The Series 3500 Trace Oxygen Transmitters feature  Alpha Omega Instrument’s long-life ambient temperature electrochemical sensor that has a functional life of up to three times that of most “fuel cell” type sensors. The enhanced mechanical design of the sensor ensures longer life, and virtually eliminates leakage of caustic electrolyte, a nagging (and expensive) problem associated with sensors that require periodic electrolyte maintenance. And, because the sensor is sealed, it is not position sensitive. In addition, unlike some electrochemical sensors, Alpha Omega Instruments readings from the Series 3500 do not require manual adjustment based on changes in the molecular weights of the sample gas i.e. helium, hydrogen, etc. a major advantage for continuous measuring applications. The output from the sensor is both linear and temperature compensated to provide optimum performance.

Now Featuring a CO2-Resistant Sensor

A nemesis for many conventional “fuel cell” type trace oxygen sensors are their inability to measure oxygen in gases containing carbon dioxide. Carbon dioxide reacts with potassium hydroxide electrolyte to form carbonic acid and in short time destroys the sensor. Not anymore. Alpha Omega Instruments offers an optional CO2 tolerant trace oxygen sensor with proprietary electrolyte. The CO2 tolerant sensor is capable of providing accurate oxygen readings in gases containing up to 100% CO2 without shortening the life of the sensor.



  • Improved reliability
  • Lower cost of ownership 
  • Improved product quality
  • Efficiency
  • Meet compliance requirements
  • Backed by global service and support

Process Insights is committed to solving our customers’ most complex analytical and process challenges.  


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EMEA +49 69 20436910
China/APAC +86 400 086 0106



  • Measurement Ranges: (parts per million) 0-10, 0-50, 0-100, 0-500, 0-1,000, 0-5,000, 0-10,000, and 0-20,000
  • Accuracy¹: ±1% of full scale (± 5% of full scale on ranges ≤ 0-5ppm)
    • ¹Stated at constant temperature and pressure
  • Linearity: + 1% of full scale.
  • Response Time: 90% of full scale response in less than 10 seconds (typical). The response time for ranges of 0-50 PPM or less depend to a great extent on the design of the sample delivery system including the materials used.
  • Sensor Type: Long-life Ambient Temperature Electrochemical Sensor (Optional CO2 Resistant Sensor Available).
  • Temperature Compensation: Standard.
  • Operating Temperature Range: 40° to 104° F (5° to 40° C) <40° F (<5° C) use heated sensor enclosure >104° F (>40° C) cooling of sample gas/sensor required
  • Warranty: Two years electronics, one year sensor


  • Series 3500 Loop Powered Trace Oxygen Transmitter: Input power 14-32 VDC
  • Analog Output: 4-20 mADC with a loop resistance of 600 ohms @ 24 VDC (consult factory for other resistance values).


  • Sample Flow Rate: 1.0 to 2.0 standard cubic feet per hour (SCFH). 0.5 to 1.0 liters/ minute (LPM).
  • Sample Gas Temperature: 40° to 104° F (5° to 40° C)
  • Sample Gas Pressure Limits: 0.1 to 1.5 psig (0.007 to 0.1 kg/cm2).
  • Entrained Solids: <3 mg/ft³: no in-line filter required >3 mg/ft³: in-line filter is required
  • Hydrocarbon Mist: <0.7 mg/ft³: no in-line filter required >0.7 mg/ft³: in-line filter is required


  • Polycarbonate, rated NEMA 4X (IP66) without optional equipment. (Optional NEMA7 explosion-proof enclosure available)
  • Dimensions: 5.5 in (139.9 mm) height. 8.8 in (223.5 mm) width. 3.4 in (86.4 mm) deep. Note: All dimensions are without optional equipment
  • Gas Connections: 1/4” stainless steel compression fittings.

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