Analyser / On-Line Analyser / Process Analyser / Process Stream Analyser / Quality Analysers / Quality Measurement Instruments (QMI). An instrument used to measure continuously and automatically a particular property or chemical composition of a process stream. The input to the instrument is a sample or portion of the process stream, either introduced continuously or at specific points in the analyser operating cycle. The sample is conditioned in a particular way, for example; flow, pressure, temperature or cleanliness. The output is a transmitted result or reading displayed on suitable read out instrumentation such as a control system screen or other operator interface. The analyser is normally located permanently within the process area.