The ABB AO2000 – LS25 is a laser gas analyzer module that is part of the ABB AO2000 integrated analyzer system and is designed for continuous measurement of the concentration of individual components in a gas mixture4. It utilizes laser technology based on the principle of single – line spectroscopy1. During measurement, a single absorption line is selected from the gas to be measured in the near – infrared spectral range, where there is no cross – sensitivity from other gases1. The absorption line is scanned, and the receiver on the opposite side detects the absorption effect of the sample gas and calculates the gas concentration accordingly1. The module comes with a transmission and receiver unit and can be used on ducts with a diameter of 0.5 – 6 m1. In practical applications, it can handle process pressures of up to 10 bar and temperatures of up to 1500 °C1. The multi – analyzer system can combine up to four analyzer modules, measuring up to six sample components2. It features automatic calibration via air calibration or an integrated calibration chamber, eliminating the need for standard cylinders, and has a self – check function to indicate when maintenance is required2. Hazardous – site – approved models comply with ATEX and GOST – R, 2G, 3G classes, and CSA Class Ⅰ, Division 2. It also provides Ethernet TCP/IP interfaces, OPC servers, PROFIBUS, and Modbus interfaces2.