Interscan started the real analytics movement in the field of gas detection, to demonstrate that at least one company is serious about assuring the best possible analytical accuracy in every measurement our instruments make. After all, the very term “gas detector,” which is far more common than “gas analyzer,” immediately reminds one of detector tubes,…
This one is courtesy of our friends at the American Chemistry Council A part-per-million can be thought of as: A credit card lying in the middle of a football field One step, on a 568–mile (914 km) walk One minute, in a two-year span A part-per-billion can be thought of as: One thousand times smaller…
Rise time to 50% of final value, rise time to 90% of final value, and fall time to 10% of original value are typical specifications presented for gas detection instruments. The 50% figure is useful when considering how fast an instrument will respond in a critical (alarm) situation, whereby “full” response is not as important…
“Minimum Detectability” is one of those instrumentation terms that is used frequently, but is seldom defined. Indeed, even though you will encounter this term on many data sheets, its definition does not appear in any of the usual learned references, including Process Instrumentation Terminology, ANSI/ISA—51.1—1979(R1993) and Standard Terminology Relating to Sampling and Analysis of Atmospheres,…
Definitions “Accuracy” as defined in the ANSI/ISA—51.1—1979 (R1993) standard Process Instrumentation Terminology is: [T]he degree of conformity of an indicated value to a recognized accepted standard value, or ideal value. Two common methods of rating or expressing accuracy are: As a percent of scale length (or percent of full scale). This rating method is most…