Calibration of resistance thermometers

DAkkS calibration of resistance thermometers (Pt100, Pt25, etc.)

Calibration of resistance thermometers (temperature sensors such as Pt100, Pt25, etc.) and indicators with DAkkS calibration certificate is done at slim ITS-90 fixed points. It is also possible to make calibrations according to the comparison method in liquid baths or calibration furnaces according to the guideline DKD-R 5-1 “Calibration of resistance thermometers”.

  • Guideline DKD-R 5-1 “Calibration of resistance thermometers” from -196°C to 962°C
  • Fixed point calibration from -189°C to 962°C
  • Turnaround time is five working days
  • Temperature probes from a length of 300mm can be calibrated
  • Temperature probes and indicators

DAkkS Uncertainty of Measurement: Calibration at Temperature Fixed Points

Fixed point Temperature Triple point Melting point Freezing point
Argon -189,3442°C 10 mK
Mercury -38,8344°C 3,5 mK
Water 0,01°C 2,5 mK
Gallium 29,7646°C 2,5 mK
Indium 156,7646°C 5,5 mK
Tin 231,928°C 7 mK 3 mK
Zinc 419,527°C 12 mK 3 mK
Aluminium 660,323°C 20 mK 5 mK
Silver 961,78°C 10 mK
The measurement uncertainties are k=2, include an ITS-90 characteristic curve (characteristic curve approximation according to ITS-90) and are given for the relevant range.

DAkkS Messunsicherheit: Vergleichskalibrierung

Vergleich mit Normal-Widerstandsthermometern



Uncertainty of measurement

-196°C in liquid nitrogen with calibration insert
DKD-R 5-1:2018
-80°C to -60°C in the calibration furnace or liquid bath
DKD-R 5-1:2018, KA16-10-05:2018-01
15 mK
 > -60°C to 90°C 10 mK
> 90°C to 200°C in a calibration furnace, liquid or solid bath
DKD-R 5-1:2018 KA16-10-05:2018-01
30 mK
> 200°C to 500°C 40 mK
> 500°C to 660°C 50 mK
> 660°C to 962°C 150 mK

Calibration at temperature fixed points

Klasmeier’s calibration service calibrates not only SPRTs but also resistance thermometers (Pt100, Pt25, Pt1000, working standard thermometers, etc.) using ITS-90 temperature fixed points for you. Each resistance thermometer is annealed at the highest temperature of use before calibration and the annealing drift is determined using the water triple point. Self-heating errors and hydrostatic pressure effects are investigated and taken into account during calibration. During each calibration, the hysteresis and the ITS-90 characteristic curve are also checked. The DAkkS calibration certificate is internationally accepted and can also be used abroad.

Short immersion depth from 300mm

By using slim and large temperature fixed points, as well as the modern ISO towers, standard thermometers of the ITS-90 (SPRTs as Pt100 or Pt25) and industrial reference thermometers (Pt100) can be calibrated from an immersion depth of 300mm with excellent measurement uncertainties.


Comparison of SPRTs with IPRTs at temperature fixed points

When calibrating reference thermometers at temperature fixed points of the ITS-90, there is the question of the required calibration points. In order to make sure that the number of temperature fixed points of the ITS-90 is also enough in the higher temperature range, we have done extensive investigations. As a result of these investigations, the following graph shows the comparison of a standard thermometer (SPRT) with a reference thermometer.


The temperature difference shows that the maximum characteristic curve difference of approx. 25mK is within the measurement uncertainty. For DAkkS calibrations in the higher temperature range, a plausibility check of the characteristic curve is done in addition to the mentioned tests. The test temperature is between the fixed point temperatures.



New digital archive Klasmeier Cloud: Calibration documents quickly and easily available

The new Klasmeier Cloud – the perfect archive for all calibration documents. From now on, our customers will find a QR code on all devices calibrated by Klasmeier, with which they can quickly and easily access our digital archive. Especially useful: In addition to all calibration documents, the contact details of the relevant contact person at Klasmeier are also always available there. So even five or more years from now, if you have any questions about your calibration product, you can find the information you need with just one click.


Questions about calibration?

Contact: Boris Kalb –