Using tunable diode laser absorption spectroscopy (TDLAS) technology, the laser analyzer 5100HD can be configured with one or two absorption cells, providing dual stream analysis and/or the measurement of multiple analytes at the same time. The tunable diode laser technique is inherently free from many problems that affect physical contact sensors, including repeated exposure to contaminants and a delayed measurement response to sudden process upsets. Two separate lasers can be installed in the instrument, sharing a common optical path through the sample. This results in significant cost savings by eliminating the need for a second analyzer in the process. Measuring combinations of water vapor, methane, hydrogen sulfide, carbon dioxide, acetylene and oxygen, the 5100HD TDLAS is designed for applications in the hydrocarbon processing and natural gas industries. Proven, laser-based measurement ensures that the sample never comes into contact with key optical components. This means that both the light source and the detector are unaffected by the gas stream, preventing contamination or damage. The 5100HD TDLAS uses a reference cell to line-lock the laser on a desired wavelength. Any minor shift in the observed spectrum is used as feedback to adjust the laser, ensuring the proper operating wavelength. Thus, there is a real-time confirmation that the laser is locked on the desired absorption line. Housed in an IP 65/Type 4X enclosure for installation in outdoor or hazardous areas, the 5100HD TDLAS can be configured with a fully integrated sample handling system and is capable of operation in a wide range of challenging environments. The 5100HD is our extractive-type TDLAS analyzer for dual analytes, or those streams with high sample dew points.