API RP 555-2013 (R2020)

Process monitors that measure and transmit information about chemical composition, physical properties, or chemical properties are known as process analyzer systems. Many of these systems were first developed for laboratory analysis. Today they are primarily used as continuous on-line analyzers.

A process monitoring system usually requires a sample conditioning system, a process analyzer, and one or more data output devices. Properly designed systems also require overall considerations as to calibration, utilities, sample disposal, safety, and systems packaging.

Process analyzers measure chemical concentrations or physical or chemical properties that can be used as control variables instead of relying on indirect physical parameters, such as pressure, temperature, and inferred data from computer models. Process analyzer systems can provide a significant economic return when incorporated into process optimization and advanced control loops or when used for product quality control.