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Comparison of the characteristics of small commercial NDIR CO2 sensor models and development of a portable CO2 measurement device.

Yasuda T, Yonemura S, Tani A - Sensors (Basel) (2012)

Bottom Line: When the correction was applied to the sensors, the accuracy of measurements improved significantly in the case of the K30 and AN100 units.In particular, in the case of K30 the relative RMS error decreased from 24% to 4%.This indicates that acceptable accuracy can be realized using the calibration method developed in this study.

View Article: PubMed Central - PubMed

Affiliation: Plant and Environmental Sciences, Department of Environmental Health Science, University of Shizuoka, Shizuoka Japan. p09402@u-shizuoka-ken.ac.jp

ABSTRACT
Many sensors have to be used simultaneously for multipoint carbon dioxide (CO(2)) observation. All the sensors should be calibrated in advance, but this is a time-consuming process. To seek a simplified calibration method, we used four commercial CO(2) sensor models and characterized their output tendencies against ambient temperature and length of use, in addition to offset characteristics. We used four samples of standard gas with different CO(2) concentrations (0, 407, 1,110, and 1,810 ppm). The outputs of K30 and AN100 models showed linear relationships with temperature and length of use. Calibration coefficients for sensor models were determined using the data from three individual sensors of the same model to minimize the relative RMS error. When the correction was applied to the sensors, the accuracy of measurements improved significantly in the case of the K30 and AN100 units. In particular, in the case of K30 the relative RMS error decreased from 24% to 4%. Hence, we have chosen K30 for developing a portable CO(2) measurement device (10 × 10 × 15 cm, 900 g). Data of CO(2) concentration, measurement time and location, temperature, humidity, and atmospheric pressure can be recorded onto a Secure Digital (SD) memory card. The CO(2) concentration in a high-school lecture room was monitored with this device. The CO(2) data, when corrected for simultaneously measured temperature, water vapor partial pressure, and atmospheric pressure, showed a good agreement with the data measured by a highly accurate CO(2) analyzer, LI-6262. This indicates that acceptable accuracy can be realized using the calibration method developed in this study.

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f1-sensors-12-03641: Experimental apparatus.

Mentions: CO2 concentrations of standard reference gases were measured with the individual sensors, and the outputs of each sensor were recorded. Four samples of the prepared standard gas (CO2_ref) with CO2 concentrations of 0, 407, 1,110, and 1,810 ppm (N2-based, Taiyo Nippon Sanso Corporation, Japan) were used. To operate the 13 sensors simultaneously, the individual sensors were arranged in a small box (230 × 170 × 40 mm, 1.5 L) made of polyethylene (Figure 1). This was similar to the Dynamic Enclosure Approach method [23,24]. To control the ambient temperature of the individual sensors, the box was placed in a temperature-controlled incubator (DKM600, Yamato). Universal asynchronous receiver transmitter (UART) cables from the individual sensors were passed through a small hole made on the wall of the incubator and connected to a computer. The output shielded cables of the temperature sensors (LM35DZ, National Semiconductor) and humidity sensors (CHS-UPS, TDK) were also passed outside and connected to a data logger (CR1000, Campbell Scientific). The flow rate of the standard gases into the box was controlled with a flow meter (FS-25CO2, Yamato).


Comparison of the characteristics of small commercial NDIR CO2 sensor models and development of a portable CO2 measurement device.

Yasuda T, Yonemura S, Tani A - Sensors (Basel) (2012)

Experimental apparatus.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376595&req=5

f1-sensors-12-03641: Experimental apparatus.
Mentions: CO2 concentrations of standard reference gases were measured with the individual sensors, and the outputs of each sensor were recorded. Four samples of the prepared standard gas (CO2_ref) with CO2 concentrations of 0, 407, 1,110, and 1,810 ppm (N2-based, Taiyo Nippon Sanso Corporation, Japan) were used. To operate the 13 sensors simultaneously, the individual sensors were arranged in a small box (230 × 170 × 40 mm, 1.5 L) made of polyethylene (Figure 1). This was similar to the Dynamic Enclosure Approach method [23,24]. To control the ambient temperature of the individual sensors, the box was placed in a temperature-controlled incubator (DKM600, Yamato). Universal asynchronous receiver transmitter (UART) cables from the individual sensors were passed through a small hole made on the wall of the incubator and connected to a computer. The output shielded cables of the temperature sensors (LM35DZ, National Semiconductor) and humidity sensors (CHS-UPS, TDK) were also passed outside and connected to a data logger (CR1000, Campbell Scientific). The flow rate of the standard gases into the box was controlled with a flow meter (FS-25CO2, Yamato).

Bottom Line: When the correction was applied to the sensors, the accuracy of measurements improved significantly in the case of the K30 and AN100 units.In particular, in the case of K30 the relative RMS error decreased from 24% to 4%.This indicates that acceptable accuracy can be realized using the calibration method developed in this study.

View Article: PubMed Central - PubMed

Affiliation: Plant and Environmental Sciences, Department of Environmental Health Science, University of Shizuoka, Shizuoka Japan. p09402@u-shizuoka-ken.ac.jp

ABSTRACT
Many sensors have to be used simultaneously for multipoint carbon dioxide (CO(2)) observation. All the sensors should be calibrated in advance, but this is a time-consuming process. To seek a simplified calibration method, we used four commercial CO(2) sensor models and characterized their output tendencies against ambient temperature and length of use, in addition to offset characteristics. We used four samples of standard gas with different CO(2) concentrations (0, 407, 1,110, and 1,810 ppm). The outputs of K30 and AN100 models showed linear relationships with temperature and length of use. Calibration coefficients for sensor models were determined using the data from three individual sensors of the same model to minimize the relative RMS error. When the correction was applied to the sensors, the accuracy of measurements improved significantly in the case of the K30 and AN100 units. In particular, in the case of K30 the relative RMS error decreased from 24% to 4%. Hence, we have chosen K30 for developing a portable CO(2) measurement device (10 × 10 × 15 cm, 900 g). Data of CO(2) concentration, measurement time and location, temperature, humidity, and atmospheric pressure can be recorded onto a Secure Digital (SD) memory card. The CO(2) concentration in a high-school lecture room was monitored with this device. The CO(2) data, when corrected for simultaneously measured temperature, water vapor partial pressure, and atmospheric pressure, showed a good agreement with the data measured by a highly accurate CO(2) analyzer, LI-6262. This indicates that acceptable accuracy can be realized using the calibration method developed in this study.

Show MeSH