
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

Accredited calibration according to DIN EN ISO/IEC 17025 (DAkkS) of a resistance thermometer at temperature fixed points (PRT, Pt 100, Pt 1000)
The accredited calibration according to DIN EN ISO/IEC 17025 (DAkkS) of resistance thermometers (Pt100, Pt1000) is performed at ITS-90 fixed points.
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Accredited calibration according to DIN EN ISO/IEC 17025 (DAkkS) of a resistance thermometer at the fixed points (melting points & triple points) of the ITS-90. Achievable DAkkS measurement uncertainties, including the ITS-90 deviation function (k=2):
Temperature Fixed Point | in °C | Measurement Uncertainty |
Argon Triple Point | -189.3442 °C | 10 mK |
Mercury Triple Point | -38.8344 °C | 3.5 mK |
Water Triple Point | 0.01 °C | 2.5 mK |
Gallium Melting Point | 29.7646 °C | 2.5 mK |
Indium Freezing Point | 156.5985 °C | 5.5 mK |
Tin Freezing Point | 231.928 °C | 7.0 mK |
Zinc Freezing Point | 419.527 °C | 12 mK |
Aluminum Freezing Point | 660.323 °C | 20 mK |
The fixed points are selected based on the temperature ranges of the ITS-90. The temperature ranges of the ITS-90 are as follows:

Prior to calibration, the resistance thermometer is sufficiently aged. Hydrostatic pressure effects occurring in the fixed-point cells are corrected. The self-heating of the resistance thermometer is examined before the start of the calibration and taken into account when presenting the calibration results. The calibration results include the resistance and W-values of the resistance thermometer, as well as two calibration curves (coefficients) calculated according to ITS-90 (with measurement currents of 0 mA and 1 mA, unless otherwise specified).
The minimum immersion depth of the resistance thermometer is:
at –189 °C: 400 mm
in range -38 °C bis 660 °C: 300 mm
The maximum outer diameter is 8 mm.
Calibration duration: approximately 5 working days or as agreed.
Accredited calibration according to DIN EN ISO/IEC 17025 (DAkkS) for resistance thermometers via comparison calibration from -196 °C to 961 °C
Accredited calibration according to DIN EN ISO/IEC 17025 (DAkkS) of a resistance thermometer in the range from -196 °C to 961 °C.
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Accredited calibration according to DIN EN ISO/IEC 17025 (DAkkS) of a resistance thermometer in a calibration bath, calibration furnace, nitrogen cryostat, or boiling nitrogen at 5 temperature points (distributed across the calibration range or as specified by the customer). The following measurement uncertainties can be achieved (depending on the test specimen):
Calibration Range | Measurement Uncertainty | Calibration Method |
-196 °C | 15 mK | Boiling Nitrogen Point |
-180 °C to -80 °C | 60 mK | Nitrogen Cryostat |
-80 °C to -60 °C | 15 mK | Calibration Bath |
-60 °C to 90 °C | 10 mK | |
90 °C to 200 °C | 30 mK | |
200 °C to 500 °C | 40 mK | Calibration Furnace |
500 °C to 660 °C | 50 mK | |
660 °C to 961 °C | 150 mK |
Prior to calibration, the resistance thermometer is sufficiently aged. The self-heating and hysteresis of the resistance thermometer are examined before the start of the calibration and are taken into account when presenting the calibration results.
Calibration duration: approximately 5 working days or as agreed.
Uncertainty of measurement during DAkkS calibration
Temperature range | Procedure | Uncertainty of measurement |
---|---|---|
-189,3442 °C | DKD-R 5-1:2018 Argon triple point | 4,0 mK |
-38,8344 °C | DKD-R 5-1:2018 Mercury triple point | 2,5 mK |
0,01 °C | DKD-R 5-1:2018 Water triple point | 1,5 mK |
29,7646 °C | DKD-R 5-1:2018 Gallium melting point | 2,0 mK |
156,5985 °C | DKD-R 5-1:2018 Indium melting point | 4,5 mK |
231,928 °C | DKD-R 5-1:2018 Tin freezing point | 3,0 mK |
231,928 °C | DKD-R 5-1:2018 Tin melting point | 6,0 mK |
419,527 °C | DKD-R 5-1:2018 Zinc freezing point | 3,0 mK |
419,527 °C | DKD-R 5-1:2018 Zinc melting point | 10 mK |
660,323 °C | DKD-R 5-1:2018 Aluminium freezing point | 5,0 mK |
660,323 °C | DKD-R 5-1:2018 Aluminium melting point | 18 mK |
961,78 °C | DKD-R 5-1:2018 Silver freezing point | 10 mK |

Temperature range | Procedure | Uncertainty of measurement |
---|---|---|
-189,3442 °C to 0 °C | DKD-R 5-1:2018 fixed points: Ar, Hg, TPW | 5,5 mK |
-38,8344 °C to 29,7646 °C | DKD-R 5-1:2018 fixed points: Hg, TPW, Ga | 3,5 mK |
0 °C to 29,7646 °C | DKD-R 5-1:2018 fixed points: TPW, Ga | 2,5 mK |
0 °C to 156,5985 °C | DKD-R 5-1:2018 fixed points: TPW, In melting points | 5,5 mK |
0 °C to 231,928 °C | DKD-R 5-1:2018 fixed points: TPW, In, Sn melting points | 7,0 mK |
0 °C to 419,527 °C | DKD-R 5-1:2018 fixed points: TPW, Sn, Zn freezing points | 4,5 mK |
0 °C to 419,527 °C | DKD-R 5-1:2018 fixed points: TPW, Sn, Zn melting points | 12 mK |
0 °C to 660,323 °C | DKD-R 5-1:2018 fixed points: TPW, Sn, Zn, Al freezing points | 7,0 mK |
0 °C to 660,323 °C | DKD-R 5-1:2018 fixed points: TPW, Sn, Zn, Al melting points | 20 mK |
0 °C to 961,78 °C | DKD-R 5-1:2018 fixed points: TPW, Sn, Zn, Al, Ag freezing points | 12 mK |

Temperature range | Procedure | Uncertainty of measurement |
---|---|---|
-196 °C | DKD-R 5-1:2018 in liquid nitrogen with compensation block | 15 mK |
-180 °C to -80 °C | DKD-R 5-1:2018 in cryostat | 60 mK |
-80 °C to -60°C | DKD-R 5-1:2018 in calibration furnace or liquid bath | 15 mK |
> -60 °C to 90 °C | DKD-R 5-1:2018 in calibration furnace or liquid bath | 10 mK |
> 90 °C to 200 °C | DKD-R 5-1:2018 in calibration furnace, liquid- or solid bath | 30 mK |
> 200 °C to 500 °C | DKD-R 5-1:2018 in calibration furnace, liquid- or solid bath | 40 mK |
> 500 °C to 660 °C | DKD-R 5-1:2018 in calibration furnace, liquid- or solid bath | 50 mK |
> 660 °C to 962 °C | DKD-R 5-1:2018 in calibration furnace, liquid- or solid bath | 0,15 K |


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 300 mm 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. 25 mK 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.
Finding the right calibration solution for you

Questions about our calibration services?
Please send your questions or enquiries to Mr Boris Kalb: