SO-411 Oxygen Sensor
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SO-411Oxygen Sensor

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Measure gaseous oxygen in the lab or field

The Apogee SO-411 Oxygen Sensor provides reliable, affordable measurement of gaseous oxygen in the laboratory, soil, and porous media. It’s used in compost piles and mine tailings, for monitoring redox potential in soils, for determination of respiration rates through measurement of O2 consumption in sealed chambers, and for measurement of O2 gradients in soil or porous media.

Plug and play technology—remote data access

Incredibly simple to set up, you just plug the oxygen sensor into the ZL6 data logger which self-identifies each sensor and automatically records important metadata such as GPS location. Get instant remote data access from the cloud wherever you are on your computer, tablet or smartphone. 

Ruggedized and robust

The SO-411 is housed in a tough polypropylene body, ideal for long-term deployment in porous media, including acidic environments (mine tailings). It also includes a diffusion head that creates a small air pocket for measurement in porous media.

Simply smarter

Designed with an internal thermistor, the oxygen sensor allows for temperature monitoring and correction of signal for temperature effects. Plus it comes with a resistive heater to raise the temperature of the membrane approximately two degrees above ambient temperature. This keeps condensation from occurring on the Teflon membrane and blocking the diffusion path of the sensor.*  

Calibration made easy

In order to accurately output oxygen concentration in units of % oxygen, all oxygen sensors must be calibrated under ambient conditions at the elevation of the location where they will be installed. The SO-411 combined with ZENTRA loggers and software make this calibration as easy as the press of a button. The ZENTRA loggers and software also make an optional zero offset with N2 gas simple and foolproof (recommended for measurements below 10% O2).  

Guaranteed to last

The rugged, reliable SO-411 Oxygen Sensor is backed by an industry-leading four-year warranty and is perfect for long-term, continuous monitoring in the lab or field. But the best part? It’s compatible with the ZL6 and ZENTRA Cloud for easy remote data access, so you can see your data anywhere, anytime.     


*NOTE: To operate the heating element, a user-supplied 12 V source must be attached to the two heater leads. For most installations a 12 V battery is the power supply of choice with either mains power charging, solar charging at remote locations, or simple periodic battery replacement if no battery charging is available. 


Measurement range

0 to 100% O2

Measurement repeatability

Less than 0.1% of mV output at 20.95% O2


Less than 1%

Long-term drift (non-stability)

1 mV per year

Oxygen consumption rate

0.1 μmol O2 per day at 20.95% O2 and 23 C (galvanic cell sensors consume O2 in a chemical reaction with the electrolyte, which produces an electrical current)

Response time

60 s

Operating environment

-20 to 60 C; 0 to 100% relative humidity (non-condensing); 60 to 114 kPa

NOTE: Electrolyte will freeze at temperatures lower than -20 C. This will not damage the sensor, but the sensor must be at a temperature of -20 C or greater in order to make measurements.

Heater voltage requirement

12 V DC continuous

Heater current draw

6.2 mA (74 mW power requirement when powered with 12 V DC source)


32 mm diameter, 68 mm length

Directional (Cosine) response

± 2% at 45 ° zenith angle, ± 5% at 75 ° zenith angle (see directional response below)


5 m or 10 m sensor cable splitting into 2 m stereo cable for ZENTRA logger and 2 m cable with pigtail termination for 12 V heater power supply.


175 g (with 5 m of lead wire)


4 years against defects in materials and workmanship

Data logger compatibility (not exclusive)

METER EM60 series, ZL6 series, ZSC


Apogee Oxygen Sensor Manual Manual PDF, 1.2MB

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