4. Standards – interchangeability

Related to the notion of "accuracy" are the sensor interchangeability tolerances imposed by various French and foreign standards for demountable thermometric systems, such as resistors, thermocouples, etc. These tolerances are given in the form of a relative or absolute error characterizing the intrinsic accuracy of the new sensor and therefore its degree of interchangeability. Depending on the type of thermometer, ISO standards give a certified accuracy. For example, for a liquid-in-glass thermometer, the error is less than one division of the scale [R2530] . A thermocouple wire is not necessarily calibrated under the same conditions as it is used... Of course, electronic measuring equipment also has its own standards.

Manufacturers' tolerances are generally quite wide, and global...