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Ametek / AEI Oxygen Analyzer (S-3A/1)

Fast Response Zirconia sensor

Photo shows both Ametek O2 and CO2 analyzers on VacuMed Metabolic Cart model MX-Ametek.


The Applied Electrochemistry Model S-3A Oxygen Analyzer continuously measures the concentration of oxygen. There are two models: The S-3A/I Single-Channel Analyzer and the S-3A/II Dual-Channel Analyzer. Both instruments feature the same high accuracy, rapid response, and excellent sensitivity.


  • High accuracy at all oxygen concentrations
  • Rapid response-ideal for accurate breath-by-breath measurements
  • High sensitivity plus exceptional stability - capable of detecting changes of 0.001% oxygen at air composition
  • Solid ceramic oxide sensing element for long term maintenance-free operation
  • Single gas calibration (room air may be used)

The Gold Standard in laboratory oxygen analysis
for over 30 years, worldwide.


A complete Model S-3A consists of a sensor, readout/control unit, and cable. When the sample gas is passed through the sensor, a voltage that is a function of the oxygen concentration of the gas is generated. This voltage is fed to the readout/control unit via a connecting cable.

The optional R-1 (Single Channel) or R-2 (Dual Channel) Flow Control Unit can be used to draw the sample through the sensor. Each flow control unit contains a pump, a needle valve, and a flowmeter for each channel. Other gas handling equipment can be used if preferred such as VacuMed's low cost flow controller below.


Speed of Response:
100 milliseconds to 90% of final value for a step change in oxygen concentration.

± 0.01% O2 on the %O2 scale, equivalent accuracy on other scales, within working range

Working Range:
Calibration gas value ± 5% of full scale value

± 0.01% oxygen in 24 hours with constant temperature and pressure

± 0.001% oxygen or equivalent on other scales

Digital Display: ± 0.01 on each scale

Analog Output:
0-5V buffered output for 0-100% O2

Sample Flow Rate:
10-300 ml/min, 50-125 ml/min recommended for most applications; for other flows, consult the factory

Flow Dependence:
± 0.02% O2 at flow rates of 50-125 ml/min, calibrated at 20.61% O2 and 95 ml/min

Additional Specifications for Model S-3A/II, Channel Delta (1-2)

± 0.003% O2

± 0.003 in any 4 hour period

± 0.001 on the digital display

Analog Outputs:
Buffered analog output of 0-10V for 0-100% O2 on channels 1 and 2;
0 to ± 10V for 0 to ± 10% O2 on channel Delta (1-2)

Requires flow controller. Dual flow controller may be used if you buy both O2 and CO2 analyzer.

18 months warranty on all Ametek products
See VacuMed No. 17001 or 17003 PC Interface to construct a VO2 measurement system.

See also VacuMed No. 17503 Low cost flow controller.

Last Updated: 28 Mar 2017

Qty Product Catalog Number Price

Ametek OXYGEN ANALYZER (S-3A/1)115 Volts 17210 12,850.00

Ametek O2 Analyzer (S-3A/I) 230 Volts 17211 12,850.00

Dual Channel Oxygen Analyzer 17250 16,600.00

Ametek Flow Controller (110V) 17240 1,800.00

Ametek Dual Flow Controller (110V) 17241 2,592.00

Ametek Flow Controller (220V) 17242 1,800.00

Ametek Dual Flow Controller (220V) 17243 2,775.00

Dryer Kit (Nafion/dessiccant Combo) 17245 900.00

VacuMed Flow Controller 17503 995.00