Pewatron's 'Smartmodul' Basic Evo series gas sensors are available for various gas types, including refrigerants commonly used in refrigeration systems. These refrigerants include R404a, R507, R410a, R22, R134a, R407a/c, R124yf, R123, R125, R290 and R744. The gas sensors are based on non-dispersive infrared absorption (NDIR). With this sensor principle, the gas quality is evaluated and infrared radiation is absorbed at a specific, characteristic wavelength. The sensors work very selectively and show virtually no cross-sensitivity to other gases. The matchbox-sized sensor module can be integrated into a wide range of applications. Data communication can take place via Modbus ASCII or RTU, allowing the module to be connected to a controller. Other features include atmospheric pressure compensation, a built-in LED status display, temperature compensation and low drift.