Measurement Uncertainty of a Temperature Measuring Chain

In order to make measurements comparable, the quality must be disclosed by specifying the measurement uncertainty. The ISO/BIPM "Guide to the Expression of Uncertainty in Measurement", typically known as "GUM" for short, and published in 1993, introduces a uniform method for determining and indicating the measurement uncertainty. This method has been adopted worldwide by calibration laboratories. However, some mathematical knowledge is required for the application. The following chapters take a simplified approach to make measurement uncertainty comprehensible for all users of temperature measuring chains. For example, errors when installing the temperature sensors and connecting the evaluation electronics can cause an increase in the measurement error. On top of this, there are the measurement uncertainty components of the sensor and the evaluation electronics themselves. Following an explanation of the measurement uncertainty components, some practical sample calculations are performed. Familiarity with the measurement uncertainty components and their orders of magnitude, empowers the user to reduce the individual components by changing the installation conditions or selection of devices. The decisive factor is always the measurement uncertainty required for a measurement task. For example, if a standard specifies limit values for the deviation of the temperature from the setpoint value, the measurement uncertainty of the measurement method used should not exceed one third of the limit value. This brochure provides a tool for assessing measurement uncertainty, in particular with the sample calculations provided in Chapter 3. If problems arise, we are happy to discuss the specific cases with our customers and provide practical assistance.