Tunable diode laser spectrometers (TDLS) allow for real-time gas analysis to increase efficiency, safety, throughput, quality, and environmental compliance. The non-contacting sensor allows measurement under severe conditions, such as high temperature, high pressure, corrosive/abrasive conditions, high dust concentration, etc. Maintenance can also be performed without taking the process offline because the TDLS is isolated from the process. The TDLS is a robust process analyzer that contributes to stable and efficient operation.