The ETG 6500 series of gas analyzers by ETG are the ideal solution for Biogas/Biomethane updgrading measurement because of their accuracy, stability, reliability, broad measurement range, and the variety of available form factors. Unlike other analyzers, ETG 6500 non-dispersive infrared (NDIR) sensor can measure multiple gases in a single instrument, using only one optical path platform. ETG analyzers have the ability to measure CO2, H2S and O2 in addition to methane, providing the optimal combination of gases measurement for Biogas/Biomethane plants. We can measure H2S using NDUV technology, which is maintenance free and does not need the replacement of Electrochemical cells. The enhanced optics and electronics of our NDIR analyzers have virtually eliminated zero drift after the initial warm up period. The temperature and pressure compensation eliminates the major causes of span drift in many NDIR instruments.