RTD Types and Equation
January 14, 2018
RTD probe Construction
January 14, 2018

RTD Standards

Two standards are available for platinum RTDs: 

  • American standard
  • European standard


There are two resistance tolerances specified in DIN/IEC751:

Class A = ±(0.15 + 0.002*t)°C or 100.00 ±0.06 Ω at 0ºC 
Class B = ±(0.3 + 0.005*t)°C or 100.00 ±0.12 Ω at 0ºC 



Maximum Operating Range = -195°C to 660°C

Interchangeability = ±.25°C at 0°C

Stability = Less than .05°C shift per year.

Nominal Operating Current = 1 milliampere

Maximum Safe Current = 20 Milliampere



  1.    Platinum
  2.    Nickel
  3.    Copper
  4.    Balco (rare



Problems associated with RTD assemblies tend to be straightforward and easily fixed. As RTD elements are susceptible to damage by vibration or mechanical shock, the most likely problem will be that the element is open circuit. Depending on the type of assembly, this can be determined easily with a multimeter.



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