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OX-A431 Oxidising Gas Sensor

OX-A431 Oxidising Gas Sensor

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OX-A431 Oxidising Gas Sensor

Product catalog summary

Performance Specifications

Sensitivity: For O₃, sensitivity ranges from -200 to -650 nA/ppm at 1ppm. For NO₂, it ranges from -200 to -550 nA/ppm at 2ppm.
Response Time: The t90 response time from zero to 1ppm is less than 45 seconds for both O₃ and NO₂.
Zero Current: In zero air at 20°C, the zero current ranges from -50 to 70 nA.
Noise: Noise is ±2 standard deviations, equivalent to 15 ppb.
Range: The performance warranty limit is 20 ppm for both gases.
Linearity: The ppm error at full scale is less than ±0.5 for both gases.
Overgas Limit: Maximum ppm for stable response to gas pulse is 50 ppm.

Lifetime Specifications

Zero Drift: Zero drift is 0 to 20 ppb equivalent change per year in lab air.
Sensitivity Drift: Sensitivity drift is less than -20 to -40% change per year in lab air.
Operating Life: The sensor has an operating life of more than 24 months until 50% of the original signal is reached.

Environmental Specifications

Temperature Sensitivity: At -20°C, sensitivity is 60 to 80% of the output at 20°C for O₃ and 50 to 80% for NO₂. At 40°C, sensitivity is 80 to 105% for O₃ and 115 to 130% for NO₂.
Zero Current: At -20°C, zero current ranges from 0 to 25 nA, and at 40°C, it ranges from 20 to 90 nA.

Cross Sensitivity

H₂S: Sensitivity is less than 100% for 5ppm H₂S.
NO: Sensitivity is less than 5% for 5ppm NO.
Cl₂: Sensitivity is less than 85% for 5ppm Cl₂.
SO₂: Sensitivity is less than -6% for 5ppm SO₂.
CO: Sensitivity is less than 0.1% for 5ppm CO.
C₂H₄: Sensitivity is less than 0.1% for 100ppm C₂H₄.
NH₃: Sensitivity is less than 0.1% for 20ppm NH₃.
H₂: Sensitivity is less than 0.1% for 100ppm H₂.
CO₂: Sensitivity is 0.1% for 5% Vol CO₂.
Halothane: Sensitivity is less than 0.1% for 100ppm Halothane.

Key Specifications

Temperature Range: -30 to 40°C
Pressure Range: 80 to 120 kPa
Humidity Range: 15 to 85% rh continuous
Storage Period: 6 months at 3 to 20°C in a sealed pot
Load Resistor: 33 to 100 Ω (AFE circuit recommended)
Weight: Less than 6g

Figures and Diagrams

Figure 1: OX-A431 Schematic Diagram showing top, bottom, and side views.
Figure 2: Sensitivity temperature dependence to 1ppm O₃.
Figure 3: Zero temperature dependence showing variation in zero output due to temperature changes.
Figure 4: Response from 200 ppb to 0 ppb O₃.
Figure 5: Sensitivity temperature dependence to 2ppm NO₂.
Figure 6: Response to 50ppb NO₂.
Figure 7: Response from 200 ppb to 0 ppb NO₂.

Additional Notes

The OX-A431 sensor detects both ozone and nitrogen dioxide, while the NO2-A43F measures only nitrogen dioxide, filtering out ozone. To calculate O₃ concentration, subtract the corrected NO2-A43F concentration from the corrected OX-A431 concentration, ensuring corrections for electronic zero offset, sensor zero offset, temperature dependence, and sensitivity calibration.

All sensors are tested at ambient environmental conditions with a 47 ohm load resistor unless otherwise stated. Customers should test under their own conditions to ensure suitability for their requirements.

Catalog excerpts

OX-A431 Oxidising Gas Sensor Ozone + Nitrogen Dioxide 4-Electrode Figure 1 OX-A431 Schematic Diagram Sensing area Oo riot obscure Specification O3 Sensing PERFORMANCE Sensitivity Response time Zero current Noise* Range Linearity Overgas limit All dimensions in millimetres (± 0.15mm) 'J Bottom View Side View nA/ppm at 1ppm O3 t90 (s) from zero to 1ppm O3 nA in zero air at 20°C ±2 standard deviations (ppb equivalent) ppm O3 limit of performance warranty ppm error at full scale, linear at zero and 20ppm O3 maximum ppm for stable response to gas pulse * Tested with Alphasense AFE low noise circuit LIFETIME Zero drift ppb equivalent change/year in lab air Sensitivity drift % change/year in lab air, monthly test Operating life months until 50% original signal (24 month warranted) sensitivity % measured gas sensitivity % measured gas sensitivity % measured gas sensitivity % measured gas sensitivity % measured gas sensitivity % measured gas sensitivity % measured gas sensitivity % measured gas sensitivity % measured gas sensitivity % measured gas KEY SPECIFICATIONS Temperature range Pressure range Humidity range Storage period Load resistor Weight °C kPa % rh continuous months @ 3 to 20°C (stored in sealed pot) Q (AFE circuit recommended) g NOTE: all sensors are tested at ambient environmental conditions, with 47 ohm load resistor, unless otherwise stated. As applications of use are outside our control, the information provided is given without legal responsibility. Customers should test under their own conditions, to ensure that the sensors are suitable for their own requirements. Alphasense Ltd, Sensor Technology House, 300 Avenue West, Skyline 120, Great Notley. CM77 7AA. UK Telephone: +44 (0) 1376 556 700 Fax: +44 (0) 1376 335 899 E-mail: [email protected] Website: www.alphasense.com

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Perf erformance Data OX-A431 Performance Data Figure 2 Sensitivity temperature dependence to 1ppm O3 130 Figure 2 shows the mean and 95% confidence levels for the temperature dependence of sensitivity at 1ppm O3. Measuring Ozone at higher temperatures requires good casing design to ensure the Ozone reaches the sensor before reacting. This data is taken from a typical batch of sensors. Figure 3 Zero temperature dependence 200 Figure 3 shows the variation in zero output of the working electrode caused by changes in temperature, expressed as nA. This data is taken from a typical batch of sensors....

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OX-A431 Oxidising Gas Sensor Ozone + Nitrogen Dioxide _4-Electrode_ Patented The OX-A431 detects both ozone and nitrogen dioxide (O3 +NO2). The NO2-A43F measures only nitrogen dioxide, filtering out ozone. Using these sensors together allows you to calculate the O3 concentration by subtracting the corrected NO2-A43F concentration from the corrected OX-A431 concentration. Before subtracting to determine ozone concentration, ensure that the signals from the two sensors have been corrected for electronic zero offset, sensor zero offset and temperature dependence, and sensitivity (nA/ppm) calibration...

Open the catalog to page 3

Perf erformance Data OX-A431 Performance Data Figure 5 Sensitivity temperature dependence to 2ppm NO2 Figure 5 shows the temperature dependence of sensitivity at 2ppm NO2. This data is taken from a typical batch of sensors. The OX-A431 shows fast response and return to baseline, even at low concentrations. Figure 7 Response from 200 ppb to 0 ppb NO2 340 Figure 7 shows response from 200ppb NO2 to 0ppb NO2. Use of Alphasense AFE circuit reduces noise to 15ppb, with the opportunity of digital smooting to reduce noise even further. Technical Specification Offset voltage is due to intentional AFE...

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OX-A431 Oxidising Gas Sensor

OX-A431 Oxidising Gas Sensor

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