This eXacal thermometer was developed to determine vertical and radial temperature profiles in calibration equipment as part of the measurement uncertainty. This is required in several directives, such as the german DKD-R 5-4 “Calibration of dry-well calibrators”, DKD-R 5-3 “Calibration of thermocouples” or DKD-R 5-1 “Calibration of resistance thermometers”. The thermometer is also suitable for measuring and setting heating zones on calibration furnaces. Of course, the thermometer can also be generally used for accurate temperature measurement.

Calibration

eXacal thermometers are calibrated in our own DAkkS calibration laboratory. The DAkkS accreditation ensures that all calibrations are traceable to national and international standards.

The calibration of eXacal resistance thermometers is carried out at ITS-90 fixed points. It is also possible to carry out calibrations according to the comparison method in liquid baths and calibration furnaces. The measurement uncertainty is calculated from many components. The largest contributions are the reproducibility, ITS-90 function, self-heating and hysteresis.

Uncertainty of measurement

The configurable DAkkS calibration includes a 3-point DAkkS comparison calibration. This ensures basic traceability. Depending on the design, the thermometers can also be calibrated with smaller measurement uncertainties at fixed temperature points.

• Small measurement uncertainties with DAkkS calibration certificate
• Temperature fixed points from mercury triple point -38.8344 °C to tin freezing point 231.928 °C
• ITS-90 standard thermometer for comparison calibration

Range	Fixed Point	Uncertainty
-38,8344°C	Mercury	5mK
0,01°C	Water	5mK
29,7646°C	Gallium	6mK
156,5985°C	Indium	9mK
231,928°C	Tin	10mK

The given measurement uncertainties correspond to k=2, include an ITS-90 function and are given for the respective range.

Technical data

Model	Pt100M
Temperature range –	-50°C to 250°C
Nominal resistance	Pt100 (100 Ohm)
typical annual drift	2,5 mk
Connection type	Four-wire
Connecting cable	temperature resistant – very low EMF stranded wires from own production
Connection	banana plugs or depending on configuration
Sheath material	Metal
Thermometer wire	silver
Dimensions
Handle	∅ 20 mm x 100 mm
diameter	4 mm
Length	400 mm
Connection cable	2 m
Detector
R0	100 Ohm ± 0,05 Ohm
Alpha	0,003850 ± 0,000005
Standard	IEC 60751:2008
tolerance	1/10 DIN
length	6 mm
recommended measuring current	1 mA
Self-heating	30 mK @ 1 mA at 29,7646 °C (Gallium melting point)
DAkkS Calibration
Fixed point calibration	5 mK to 10 mK
Comparison calibration	10 mK to 25 mK