Datasheet Specifications

The measurement uncertainty of a high-quality measurement system is usually stated in the data sheet. Let us look at an example:

\[ \begin{gathered} \text{Measuring range: } T = [-30\,°\mathrm{C} \ldots 200\,°\mathrm{C}] \\[6pt] \text{Measurement uncertainty: } \Delta T = \pm\left(0.15\,°\mathrm{C} + 0.002 \cdot |T|\right) \end{gathered} \]

The measuring range in the square brackets lies between −30 °C and 200 °C. Within this range, the measurement uncertainty is as stated; outside the range, it is probably higher than stated here. There is a constant uncertainty of ±0.15 °C for every measured value within the measuring range. An uncertainty term that depends on the measured value is added to it. At T = 0 °C, the uncertainty remains ±0.15 °C. At T = 100 °C, the term 0.002 ∙ 100 °C = 0.2 °C is added. Overall, the uncertainty at T = 100 °C is ±0.35 °C.

The measurement uncertainty is also often given in percent. The constant part is then given as a percentage of the measuring range. The part that depends on the measured value is given as a percentage of the measured value.

\[ \begin{gathered} \text{Measuring range: } T = [-30\,°\mathrm{C} \ldots 200\,°\mathrm{C}]\text{:} \\[6pt] \rightarrow 230\,°\mathrm{C} \text{ wide measuring range (MR)} \\[6pt] 0.15\,°\mathrm{C} \text{ corresponds to } 0.065\,\% \text{ of the measuring range} \\[6pt] 0.002 \text{ corresponds to } 0.2\,\% \text{ of the measured value (MV)} \\[6pt] \text{Measurement uncertainty: } \Delta T = \pm\left(0.065\,\%\ (\mathrm{MR}) + 0.2\,\%\ (\mathrm{MV})\right) \end{gathered} \]