Trace Oxygen Transmitters Series 3500/3510

Trace Oxygen Transmitters Series 3500/3510

The Trace Oxygen Transmitters Series 3500/3510 are AOI 3500 3510 trace oxygen transmitter blind transmitters designed to provide exceptional performance, accuracy, and stability.  

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).  A 4-20 mADC output is provided that can be used with a data logger, recorder, PLC, DCS, etc. Options include pressure regulators, flow meters, sample filters, and explosion proof (NEMA 7) housings.

The Series 3510 Trace Oxygen Transmitter is the AC powered (115/230 VAC, 50-60 Hz) counterpart to the Series 3500 and is recommended when  AC power is available or preferred. Also, available in optional 24VDC. IIn addition to the optional equipment mentioned above, the Series 3510 can be equipped with sample pumps, solenoid valves, and flowmeters. A 4-20 mADC analog output is provided.

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: A factory Certificate of Performance Verification and Calibration is included at no additional charge. The product performance is verified in accordance with manufacturing specifications using a National Institute of Standards and Technology (NIST) traceable transfer calibrated standard gas mix.
  •  NEMA 4 Enclosure Greater installation flexibility with a dust and waterproof enclosure.




  • 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)
  • 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


  • Enclosure: Polycarbonate, rated NEMA 4X (IP66) without optional equipment.
  • 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.

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.

Questions? We’re here to help.

Alpha Omega Instruments
4140 World Houston Pkwy, Suite 180
Houston, TX 77032 USA