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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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Relationship between CTCday and length of use in the case of K30 and AN100 (n = 3).
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f5-sensors-12-03641: Relationship between CTCday and length of use in the case of K30 and AN100 (n = 3).

Mentions: The relationship between CTCday and length of use (Figure 5) shows the linearity in the case of K30 and AN100. αT and αday were determined to minimize the RRMS error between CO2_std and CO2_correct obtained from Equation (2). RRMS errors calculated using αT and αday determined for individual sensors and for sensor models are listed in Table 2. RRMS errors determined for individual sensors were lower than those determined for sensor models, and the difference ranged from 4.8% to 23.6%. RRMS errors decreased in both cases with an increase in the number of correction factors considered in the K30 and AN100 sensor models, suggesting that these corrections successfully improve the accuracy of the sensors. In particular, K30 had the highest accuracy, comparable to the reference sensor GMM222C, even when the same coefficients were applied to three sensors of the K30 model (Figure 6). This result suggests that the coefficients determined for sensor models using all the data from three individual sensors can be applied for sensor correction for the K30 model.


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)

Relationship between CTCday and length of use in the case of K30 and AN100 (n = 3).
© Copyright Policy
Related In: Results  -  Collection

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

f5-sensors-12-03641: Relationship between CTCday and length of use in the case of K30 and AN100 (n = 3).
Mentions: The relationship between CTCday and length of use (Figure 5) shows the linearity in the case of K30 and AN100. αT and αday were determined to minimize the RRMS error between CO2_std and CO2_correct obtained from Equation (2). RRMS errors calculated using αT and αday determined for individual sensors and for sensor models are listed in Table 2. RRMS errors determined for individual sensors were lower than those determined for sensor models, and the difference ranged from 4.8% to 23.6%. RRMS errors decreased in both cases with an increase in the number of correction factors considered in the K30 and AN100 sensor models, suggesting that these corrections successfully improve the accuracy of the sensors. In particular, K30 had the highest accuracy, comparable to the reference sensor GMM222C, even when the same coefficients were applied to three sensors of the K30 model (Figure 6). This result suggests that the coefficients determined for sensor models using all the data from three individual sensors can be applied for sensor correction for the K30 model.

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