Reference condition
A reference condition is a general condition that is prescribed or agreed for an investigation and must be kept constant. In many areas of science it serves to compare the results of different studies.
The term has a particular meaning in measurement technology . There, a reference condition is a specification for an operating condition of a measuring device during a quality check. To ensure that reference conditions are as uniform as possible, these are partly the subject of standardization .
Metrological application
The aim of a measurement is to obtain a display or other quantitative statement about a measured variable , i.e. about the physical variable to which the measurement applies. Very often, however, the measuring device reacts with a change in its display not only to a change in its measured variable, but also to changes in other variables. A variable that influences the measured value but is not the subject of the measurement is called an influencing variable . The influence is always irrelevant if a measuring device is operated under the same conditions as during its adjustment or test . A reference condition to be complied with is therefore a specification for a physical variable acting on the measuring device to which the measurement does not apply, e.g. B. for the temperature of a pressure gauge.
In order to get the smallest possible measurement deviation , a measuring device should be operated under reference conditions. The remaining measurement deviation is called the intrinsic deviation . Insofar as a manufacturer guarantees a limit deviation for the intrinsic deviation of his measuring device , this only applies if all reference conditions are observed and only within the measuring range .
Information
A reference condition for a physical quantity can be specified
- as a reference value, e.g. B. 23 ° C (with permissible deviations, e.g. ± 2 ° C) or
- as a reference range, e.g. B. 45 ... 65 Hz.
In addition, a limit deviation is sometimes specified for the influencing effect of the respective influencing variable, insofar as this is not on the reference condition but is in a nominal range of use to be specified . There is extensive standardization in EN 60051 for direct-acting electrical measuring devices with a scale display .