SILAREX from smartGAS Applications such as the emission measurement of several gases like CO2, CO and SO2 or the measurement of TOC (Total Organic Carbon) require multi-channel sensors. SILAREX gas sensors have been developed for this application case and enable parallel concentration measurement of up to three measuring gases or three detection ranges with one single NDIR gas sensor. The cross-sensitivities of the individual gases are compensated directly inside the SILAREX sensor, providing the user with fully prepared and corrected measuring values via Modbus ASCII / RTU for further processing. Compared to measuring with three individual sensors, the advantages are obvious: Only one sensor needs to be calibrated and maintained; varying sample preparation, different accuracies or life cycles of the sensors do not need to be considered.