Sensors are used for process monitoring and for process control. These are essential elements of safe and profitable plant operation that can be achieved only if the proper sensors are selected and installed in the correct locations. While sensors differ greatly in their physical principles, their selection can be guided by the analysis of a small set of issues, which are will be presented in next posts.
When defining sensor requirements and principles, the engineer should use terminology that has a unique meaning, which is not easily achieved. Therefore, the engineer should refer to accepted standards and use the terminology provided in the standards. For instrumentation, standards published by the ISA (formerly, Instrument Society of America) are the most relevant. This post and the next posts will use terms from the ISA wherever possible.