| 摘要 |
A gas sensor for determining a concentration of a predetermined gas in a measurement volume E comprises light source C and detector J to receive light passed through the measurement volume. During a first measurement period, the detector makes a first measurement of an amount of light received in at least one wavelength band absorbed by the gas. The first measurement is compared to a predetermined threshold value. If the threshold is crossed, during a second measurement period the detector makes a second measurement of an amount of light received in at least one wavelength band absorbed by the gas. Gas concentration is calculated using the first and/or second measurement. A sampling rate, the light intensity or emitting surface area of the light source may be varied between first and second measurement periods. A further embodiment specifies a wireless sensor and the second measurement using a greater amount of light than the first. |
