How does a Pt100 sensor work?

SKS Sensors® Pt100 temperature sensor

  • Based on resistance measurement principle
  • Material is platinum and resistance value is 100 ohm at temperature 0 °C
  • Platinum has a positive resistance temperature factor; resistance increases with rising temperature
  • Resistance variation is a function of temperature; 0,39 ohm/1 °C
  • Long term stability is the main difference compared to other temperature measuring methods; one year value is better than 0,2 ohm/0 °C.

Pt100 sensor structures

  • One sensor structure can include also several Pt100 resistances: 1, 2 or 3 × Pt-100 (most common is 1 × Pt-100).
  • For different measuring circuits the resistance element can be produced in different versions: 2-, 3- or 4-wire connection (most accurate is 4-wire).
  • Even as a standard version the industrial Pt100 sensor is vibration proof and additionally it can be produced as an extra vibration proof version for extreme circumstances.

Pt100 accuracy classes

Standard IEC 60751 defines Pt100 resistance accuracy classes and corresponding tolerances. Briefly, the tolerance classes for wire wound resistors used for SKS Sensors® are:

  • Class A

    • applies on temperature range -100 ... +450 °C
    • 0 °C = ± 0,15 °C, 100 °C = ± 0,35 °C
    • SKS Sensors® standard, 4-wire connection recommended

  • Class B

    • applies on temperature range -196 ... +600 °C
    • 0 °C = ± 0,3 °C, 100 °C = ± 0,8 °C

  • Class B 1/3 DIN

    • divided value, based on Class B, not applicable over the whole measuring range
    • 0 °C = ± 0,3 / 3 °C

  • Class B 1/10 DIN

    • divided value, based on Class B, not applicable over the whole measuring range
    • 0 °C = ± 0,3 / 10 °C

Pt100 wire colors

  • Colors of wires attached to Pt100 resistance are defined in standard EN 60751. Wire colors according to this standard for 2-, 3- and 4-wire connection are presented within each sensor type and additionally clicking the image below.
Pt100 wire colors acc. to EN 60751


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