sentences: )or from sophisticated chemical analyzers (providing composition of one or more components in the chemical stream), are typically used as inputs to process control algorithms to give a "snapshot" of the process operation and to control the process to ensure it is operating efficiently and safely
  
  Traditionally, most of the measurements (with the exception of temperature, pressure and flow) were performed "off-line" by taking a sample from the process and analyzing it in the laboratory.Beginning in the latter of part of the 1930s a trend aimed at moving the analysis from the laboratory to the process plant began.