The spectrometer utilizes a tunable Fabry-Perot assembly that provides wavelength scanning along with advanced spectral processing that can produce response times as fast as 1 to 10 seconds. Additional measurement options are available depending on the application. This includes component analysis for the HPI market such as ethylene, propylenes, and butenes (Canada, Mexico and Middle East). Sampling is with a flowthrough cell, suitable for continuous, online, unattended operation. The analyzer does not require carrier gas, fuel gas or on-site calibration gas. The standard Envent system configuration provides measurements of up to 100% methane, 25% ethane, 25% propane, 10% butanes and 5% pentanes, 100% H2S and 100% CO2. Diatomic compounds such as nitrogen, oxygen and hydrogen are not measured directly and are combined and reported as one group of unmeasured inert gases.