Precise calibration for all resistance thermometers – flexible, accredited, reliable
We calibrate your resistance thermometers (temperature sensors such as Pt100, Pt25, etc.) and direct-reading measuring devices using state-of-the-art methods – either by comparison or fixed-point calibration. Our accredited laboratory (DIN EN ISO/IEC 17025) provides you with internationally recognized calibration certificates (DAkkS-compliant) with individually tailored measurement uncertainties – precisely tailored to your application.
Our services
Accredited calibration of resistance thermometers and direct-reading measuring instruments
Temperature range: -196°C to +961°C – complete coverage of ITS-90
Calibration method: fixed-point calibration at ITS-90 fixed points or comparison calibration
Proficiency testing according to DIN EN ISO/IEC 17043
Repair service for thermometers in our own factory
Your benefits at a glance
Various calibration methods
The choice is yours:
Fixed-point calibration
at melting points
(economical, low measurement uncertainty)
Comparative calibration
(freely selectable measuring points, cost-effective)
Kurze Durchlaufzeiten von 5 Arbeitstagen
→ Minimieren Sie Ausfallzeiten – Ihre Widerstandshermometer sind schnell wieder im Einsatz.
Kleine Messunsicherheiten
→ Profitieren Sie von höchster Präzision:
Wir holen das Beste aus Ihrem Thermometer heraus.
Everything from a single source
→ Complete package from calibration and suitability testing to repairs – all at Klasmeier.
Central location in Fulda
→ Perfect accessibility – bring your thermometer in person or use our secure courier service.
Paperless documentation
→ Accessible at any time, legally binding signature.
Complete transparency and security via our modern cloud solution.
Measurement uncertainties in accredited calibration of resistance thermometers according to DIN EN ISO/IEC 17025 (DAkkS)
| Measuring range | Procedure | Measurement uncertainty |
|---|---|---|
| -189,3442 °C to 0 °C | DKD-R 5-1 Fixed points: Ar, Hg, TPW | 5,5 mK |
| -38,8344 °C to 29,7646 °C | DKD-R 5-1 Fixed points: Hg, TPW, Ga | 3,5 mK |
| 0 °C to 29,7646 °C | DKD-R 5-1 Fixed points: TPW, Ga | 2,5 mK |
| 0 °C to 156,5985 °C | DKD-R 5-1 Fixed points: TPW, In Melting Points | 5,5 mK |
| 0 °C to 231,928 °C | DKD-R 5-1 Fixed points: TPW, In, Sn Melting Points | 7,0 mK |
| 0 °C to 419,527 °C | DKD-R 5-1 Fixed points: TPW, Sn, Zn Melting Points | 12 mK |
| 0 °C to 660,323 °C | DKD-R 5-1 Fixed points: TPW, Sn, Zn, Al Melting Points | 20 mK |
| Measuring range | Procedure | Measurement uncertainty |
|---|---|---|
| -196 °C | DKD-R 5-1 (DIN EN IEC 60751) in liquid nitrogen with compensation block | 15 mK |
| -180 °C to -80 °C | DKD-R 5-1 (DIN EN IEC 60751) in the cryostat | 60 mK |
| -80 °C to -60°C > -60 °C to 90 °C | DKD-R 5-1 (DIN EN IEC 60751) in a calibration oven or liquid bath | 15 mK 10 mK |
| > 90 °C to 200 °C > 200 °C to 500 °C > 500 °C to 660 °C > 660 °C to 962 °C | DKD-R 5-1 (DIN EN IEC 60751) in a calibration furnace, liquid or solid bath | 30 mK 40 mK 50 mK 0,15 K |
Requirements for the calibration of resistance thermometers
| Sensor type | Temperature range | Minimum immersion depth | Max. diameter | Note |
| PRT | -196 °C | 300 mm | <8 mm | Boiling point of nitrogen |
| PRT | -180 °C to -81 °C | 480 mm | <7,5 mm | Low-temperature cryostat |
| PRT | -80 °C to 230 °C | 100 mm | – | Calibration bath, good homogeneity |
| PRT | 231 °C to 700 °C | 300 mm | <8 mm | Calibration furnace |
| PRT | 701 °C to 962 °C | 450 mm | <8 mm | High temperatures, greater depth required |
| Thermocouple | 196 °C | 300 mm | <8 mm | Boiling point of nitrogen |
| Thermocouple | -180 °C to -81 °C | 480 mm | <7,5 mm | Low-temperature cryostat |
| Thermocouple | -80 °C to 230 °C | 100 mm | – | Calibration bath |
| Thermocouple | 231 °C to 1200 °C | 190 mm | <8 mm | Calibration bath |
| Au/Pt & Pt/Pd | 0 °C to 1200 °C | 480 mm | <8 mm | Noble metal thermocouple |
This is why our fixed point calibration is particularly reliable
We calibrate not only SPRTs, but also all types of resistance thermometers at official ITS-90 temperature fixed points—with a clear goal: reliable, long-term stable measurement results for your applications.
Our process includes:
- Aging at maximum operating temperature
- Determination of aging drift at the triple point of water
- Investigation of self-heating errors and pressure effects
- Hysteresis testing and ITS-90 characteristic curve analysis
The result: a fully documented DAkkS-compliant calibration certificate that is internationally recognized—ideal for demanding applications and audits.
Calibration possible from a small immersion depth
Thanks to our specially developed calibration method at narrow temperature fixed points and our modern ISO tower technology, we can calibrate your resistance thermometers from an immersion depth of just 300 mm – with outstanding measurement uncertainty.
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.
Added value for audits & consulting
We can offer you support with audit preparations:
Accredited calibrations across the entire ITS-90 range
→ This means you are perfectly prepared for your next assessment.
Proficiency tests to confirm your measurement uncertainties
Practical tips and advice from an accredited laboratory
→ So that your temperature measurement technology not only looks good on paper, but also performs well in everyday use
Finding the right calibration solution for you
Questions about our calibration services?
Please send your questions or enquiries to Mr Boris Kalb:
Request calibration
What are the costs involved in calibrating resistance thermometers?
When you have a platinum resistance thermometer (PRT) calibrated in our accredited calibration laboratory, the costs always consist of two components:
- the basic costs for calibration
- the costs per selected calibration point
Depending on the temperature range, nitrogen costs may also be incurred.
1. Basic costs (mandatory component of every calibration)
- kk-1436 – Basic cost comparison calibration for PRT: €145
The basic costs include:
• Issuance of an accredited calibration certificate in accordance with DIN EN ISO/IEC 17025 (DAkkS)
• Stabilization of the thermometer through thermal treatment
• Determination of self-heating and hysteresis (both are documented in the calibration certificate)
• Testing and evaluation by our specialists
2. Cost per calibration point
Depending on the temperature range in which you use your thermometer, suitable calibration points can be selected. We perform calibrations with a minimum of 3 calibration points – 5 calibration points are recommended for reliable characterization.
- kk-1476 – Calibration point -180 °C to -81 °C: € 195
(additional nitrogen costs will be charged, see below) - kk-1437 – Calibration point -196 °C (nitrogen boiling point): €130
(additional nitrogen costs will be charged, see below) - kk-1438 – Calibration point -80 °C to +230 °C: € 105
- kk-1439 – Calibration point +231 °C to +962 °C: € 130
3. Nitrogen costs (only at low temperatures)
For calibrations in the cryostat or at -196 °C, liquid nitrogen must be used. This is charged at a flat rate per calibration: - kk-1477 – Nitrogen (50 l) for cryostat: € 490 (for measurements in the range -180 °C to -81 °C)
- kk-1478 – Nitrogen (10 l) for -196 °C calibration: € 100
4. Sample calculation
A typical PRT is calibrated at 5 calibration points, for example:
0 °C, 100 °C, 200 °C, 400 °C, 660 °C
The costs are then calculated as follows: - 145 € basic cost (kk-1436)
- 5 × 105–130 € depending on temperature range
- Selecting 3 calibration points in the middle range (e.g., 0 °C, 100 °C, 200 °C) therefore costs around 460 € net.
5. Quantity discounts
If several thermometers are calibrated at the same temperatures at the same time, we can offer you attractive volume discounts: - 5 or more items: 15%
- 10 or more items: 30%
Summary
The total cost of calibration therefore depends on: - the one-time basic costs (kk-1436)
- the number and selection of calibration points (kk-1437 to kk-1439, kk-1476)
- any nitrogen costs (kk-1477, kk-1478)