Abstract: A gas sensor which works according to the principle of thermal conductivity is functionally tested. In the method, a calibration cycle is conducted in which a membrane of the gas sensor is immersed in a fluid calibration medium having a known concentration of a target gas. After the calibration cycle, a measurement chamber of the gas sensor is purged with a purging gas. Then, a measuring cycle is conducted, using a thermal conductivity sensor to measure the target gas in the measurement chamber. Using a calibration baseline established from the calibration cycle and a measurement baseline in the measurement cycle, a baseline comparison value is obtained and compared to a predetermined baseline threshold value. An error message, indicating a malfunction in the purging gas supply, is generated when the baseline comparison value exceeds the predetermined baseline threshold value.

Abstract: A gas sensor which works according to the principle of thermal conductivity is functionally tested. In the method, a calibration cycle is conducted in which a membrane of the gas sensor is immersed in a fluid calibration medium having a known concentration of a target gas. After the calibration cycle, a measurement chamber of the gas sensor is purged with a purging gas. Then, a measuring cycle is conducted, using a thermal conductivity sensor to measure the target gas in the measurement chamber. Using a calibration baseline established from the calibration cycle and a measurement baseline in the measurement cycle, a baseline comparison value is obtained and compared to a predetermined baseline threshold value. An error message, indicating a malfunction in the purging gas supply, is generated when the baseline comparison value exceeds the predetermined baseline threshold value.