About Resistance Temperature Detectors

A resistance temperature detector (RTD) operates on the principle that a change in the temperature of a metal causes a corresponding change in that metal’s electrical resistance. The resistance of the RTD increases as the temperature rises. SOR can provide a replacement for any failed thermocouple, RTD, or temperature assembly.

In most process applications, the temperature sensor is inserted into a thermowell or protection tube. This protects the sensor from its environment and facilitates easy maintenance. These assemblies generally consist of a head, nipple-union-nipple, and thermowell.



  • Every RTD is 100% tested for accuracy and continuity after the manufacturing process


Multiple Design Options

  • Thin film RTD’s are standard, with wire wound designs available
    316SS standard sheath material, with other materials and coatings available


Tiers of Accuracy for Different Applications

  • Class B, Class A, and the 1700 A tolerances provide different tiers of accuracy
    Two wire, three wire, and four wire configurations also give the customer different levels of accuracy


Large Temperature Range Capabilities

  • Some design types have temperature ratings down to -200ºF (-129ºC) and up to 900ºF (48ºC)