The sensor is used to determine the quality of the air in ventilation ducts and technical facilities. Measurement results can be displayed via the Modbus. Mentioning the channel sensor of air quality it means VOC/-a detection sensor of the mixed gases. By means of the corresponding algorithm in the device CO2-equivalent is displayed as the smell emission covers CO2 value (see tab.). Continued drifting and ageing of the air quality channel sensor caused by the operation can be eliminated by regular automatic calibration.