SO-411 SDI-12: Soil Response Thermistor Reference Oxygen Sensor

​The SO-411 has a standard response time of 60 seconds and is designed for use in soil applications.

  • Product Name:Soil Response Thermistor Reference Oxygen Sensor
  • Item No.:SO-411 SDI-12
  • Manufacturers:Apogee
  • Country of Origin:USA

The SO-411 has a standard response time of 60 seconds and is designed for use in soil applications. It comes with a thermistor temperature sensor to correct for temperature changes and a restive heater to raise the temperature of the membrane approximately two degrees above ambient temperature to keep condensation from occurring on the Teflon membrane and blocking the diffusion path of the sensor. Typical applications include measurement of O2 in laboratory experiments, monitoring gaseous O2 in indoor environments for climate control, monitoring of O2 levels in compost piles and mine sailings, monitoring redox potential in soils, and determination of respiration rates through measurement of O2 consumption in sealed chambers or measurement of O2 gradients in soil/porous media.

Input Voltage Requirement    5.5 to 24 V DC

Current Drain    0.6 mA (quiescent); 1.3 mA (active)

Measurement Range    0 to 100 % O₂

Measurement Repeatability    Less than 0.1 % of mV output at 20.95 % O₂

Non-linearity    Less than 1 %

Long-term Drift (Non-stability)    1 mV per year

Oxygen Consumption Rate    2.2 µmol O₂ per day at 20.95 % O₂ and 23 C

Response Time    60 s

Operating Environment    -20 to 60 C, 0 to 100 % relative humidity (non-condensing); 60 to 140 kPa

Input Voltage Requirement    12 V DC continuous (for heater), 2.5 V DC excitation (for thermistor)

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

Thermistor Current Drain    0.1 mA DC at 70 C (maximum, assuming input excitation of 2.5 V DC)

Dimensions    32 mm diameter, 68 mm length

Mass    175 g (with 5 m of lead wire)

Warranty    4 years against defects in materials and workmanship