SFC5500/SFM5500 Mass Flow Controllers/Meters Sensirion SFC5500/SFM5500 Mass Flow Controllers/Meters are digital multi-gas CMOSens®-based devices that measure gas mass flow by means of the calorimetric principle based on heat transfer. The controllers/meters achieve unmatched ratings for speed, accuracy, and repeatability, at a very attractive system cost. A heater element on a thermally insulated membrane and two thermopiles located upstream and downstream are integrated on a single silicon chip. In the presence of gas flow, the temperature distribution up and downstream is disturbed. This asymmetry is then measured. A larger channel design makes the device more resistant to particles, clogging, and humidified gases. Due to the compact single-chip design and mounting between metal parts, CMOSens®-based sensors are also highly resistant to electromagnetic disturbances (EMC).