Temperature difference thermometer Pt100 Model HD (-100 °C … 660 °C)

Temperature difference thermometer
Pt100 Model HD
(-100 °C … 660 °C)

Temperature difference thermometer for determining vertical temperature gradients and precise temperature measurement.

  • Temperature range: -100 °C tio 660 °C
  • Small measurement uncertainties: 6 mK to 25 mK
  • Measurement of vertical temperature gradients
  • Temperature standard and temperature difference thermometer

The thermometer for temperature difference measurement is a practical tool for daily laboratory work. The thermometer makes work easier when:

  • Determining of vertical temperature gradients
    Vertical temperature gradients must be measured as part of the measurement uncertainty of a calibration (e.g. according to DKD-R 5-4 “Calibration of block calibrators”, DKD-R 5-3 “Calibration of thermocouples” or DKD-R 5-1 “Calibration of resistance thermometers”).
  • Optimising calibration furnaces
    When optimising heating zones on calibration furnaces, precise temperature differences must be measured.
  • Precise temperature standard
    The main measuring point of the differential thermometer corresponds to the design of the eXacal PT 100 H and can be calibrated with the same measurement uncertainties. This means that the differential thermometer can be used not only for measuring temperature differences but also as a temperature standard.

The differential thermometer has two Pt 100 temperature sensors positioned at the bottom of the thermometer and at a distance of 4 cm.

Sketch of the differential thermometer


Uncertainty of Measurement

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

The calibration of the 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 calibration baths and calibration ovens. The measurement uncertainty is calculated from many components. The largest contributions are reproducibility, ITS-90 characteristic, self-heating and hysteresis.

With the differential thermometer, the main measuring point is calibrated at fixed temperature points. The second measuring point is measured by a differential measurement at maximum immersion depth in a heat pipe with an extremely good vertical profile.

  • Small measurement with DAkkS calibration certificate
  • Temperature fixed points from mercury triple point -38,8344 °C to aluminium solidification point 660,323 °C
  • Differential measurement in a heat pipe / heat pipe furnace

Bereich Verfahren Messunsicherheit
-38,8344 °C Mercury triple point 6 mK
0,01 °C Water triple point 6 mK
29,7646 °C Gallium melting point 6 mK
156,5985 °C Indium melting point 10 mK
231,928 °C Tin melting point 11 mK
419,527 °C Zinc melting point 21 mK
660,323 °C Aluminium freezing point 25 mK

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


Technical data

Model eXacal Pt100 HD
Temperature range  -100 °C bis 660 °C
Nominal resistors  Pt100 (100 Ohm)
typical annual drift  2,5 mK
Connection type  Four-wire
Connection  Banana plugs or depending on configuration
Sheat material  Metal
Thermometer wire  Platin
Handle  ∅ 20 mm x 100 mm
Diameter  6 mm
Length  500 mm
Connection cable  2 m
Measuring resistors / Temperature sensors
R0  100 Ohm ± 0,05 Ohm (High-Temperature Measuring resistors)
Alpha  0,003850 ± 0,000005
Norm  IEC 60751:2008
Length  15 mm
Recommended measuring current  1 mA
Self heating  4 mK
Calibration (main measuring point)
Fixed point calibration  6 mK bis 25 mK
Comparison calibration  16 mK bis 50 mK



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