Title: Calibration of resistance thermometers : Guideline DKD-R 5-1
Authors: Augustin, Silke, TU Ilmenau, llmenau
Bünger, Lars, Physikalisch-Technische Bundesanstalt (PTB), Fachbereich 7.4, Temperatur
Friederici, Sven, Physikalisch-Technische Bundesanstalt (PTB), Fachbereich 7.4, Temperatur
Hager, Helmut, Techmetrics GmbH, Winnenden
Mammen, Helge

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Contributors: HostingInstitution: Physikalisch-Technische Bundesanstalt (PTB), ISNI: 0000 0001 2186 1887
Resource Type: Text / Technical Requirement
Publisher: Physikalisch-Technische Bundesanstalt (PTB)
Rights: https://creativecommons.org/licenses/by-nc-nd/3.0/de/
CC by-nc-nd 3.0
Relationships: IsVariantFormOf: DOI 10.7795/550.20231130
Dates: Available: 2023-12-08
Created: 2023-11
File: Download File (application/pdf) 1.38 MB (1451815 Bytes)
MD5 Checksum: 6bea50416af3cfe92d2d6f57dc52fce1
SHA256 Checksum: b0b0910375e600d96c87e74edc3dd87f53933a237f8ad77217da96cee21a065a
Keywords: DKD guideline ; resistance thermometer ; calibration ; SPRT ; IPRT ; NTC ; PTC ; ITS-90
Abstract: This guideline has been prepared to define the technical requirements necessary for the calibration of resistance thermometers in accredited calibration laboratories. In many cases, the hysteresis effect has turned out to be the largest contribution to the measurement uncertainty, so it will be discussed in more detail. There are also references to further literature and documents of a higher level.

This guideline specifically covers the calibration of
· standard platinum resistance thermometers (SPRT); temperature range: -189.3442 °C to 961.78 °C)
· industrial platinum resistance thermometers according to DIN EN 60751 in the temperature range from -200 °C to 850 °C
· resistance thermometers made of other metallic conductors (e.g., Cu, Ni)
· semiconductor resistance thermometers (thermistors: NTC, PTC)

Furthermore, the guideline analogously applies to:
· direct-reading electronic thermometers with resistance sensor,
· electronic thermometers with resistance sensor and digital interface,
· data loggers with a resistance sensor,
· resistance thermometers with a transmitter and an analogue output signal

For fixed-point calibrations of standard platinum resistance thermometers (SPRT) which meet the requirements for interpolation instruments of the International Temperature Scale of 1990 (ITS-90), higher-level guidelines apply]. These are developed and updated by the Consultative Committee for Thermometry (CCT). It is also possible to calibrate standard platinum resistance thermometers using the comparison method described here. However, the user should bear in mind that calibration at the defining fixed points of the ITS-90 means that only significantly lower measurement uncertainties can be achieved.

The results of a calibration are only valid within the calibration range between the maximum and minimum calibration temperature. The only permissible exception is within the temperature range of approximately 77.3 K to 83.8058 K. If an ITS-90-compliant standard thermometer has been calibrated in the range between the water triple point (273.16 K) and the argon triple point (83.8058 K), the calibration function may be extrapolated to approx. 77.3 K (boiling point of nitrogen). The measurement uncertainty for the extrapolated range must be increased accordingly.
Citation: Guideline DKD-R 5-1 Calibration of resistance thermometers, Edition 11/2023, Revision 0, Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin. DOI: 10.7795/550.20231207