This series of detectors adopts integrated functional module design, which is convenient for on-site hot swapping and replacement. It can be equipped with various types of sensors, such as catalytic sensor, semiconductor sensor, electrochemical sensor, infrared (IR) sensor, photoion (PID) sensor, etc. and can detect various toxic and combustible gas concentrations (ppm /% LEL /% VOL) on site. The detector has the characteristics of flexible combination, quick and easy replacement, stable performance, good consistency, high sensitivity, low power consumption, multiple outputs and optional detection methods. It is widely used in petroleum, chemical industry, pharmacy, steel, special industrial plants and other places with combustible or toxic and harmful gases.