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THERMOCOUPLES

NFPA TIE ROD PNEUMATIC

AND HYDRAULIC CYLINDERS

LINEAR VALVE ACTUATORS

RTD’S 101

Temperature Coefficient


The standard temperature coefficient DIN 43760 of platinum wire is: α = 0.00385. For a resistance of 100 ohms at 0°C, this corrsponds to + 0,385 ohm per °C which is the average curve from 0°C to 100°C. There exists a large variety of RTD’s that have different coeffcients and ohm values at 0°C. However, the most common RTD is that with the above example, PT100, with a coeffficent of 0.00385 and an ohm value of 0°C at 100 ohms. This is what the following pages’ calculations and explanations will be based on.


International Standards DIN 43760 (IEC 751, BS-1904, JIS C1604)
Parameter Class A Class B
R0 100Ω ±0,06% 100Ω ±0,12%
Alpha, α 0,00385 ±0,000063 0,00385 ±0,000063
Range -200°C à 650°C -200°c à 850°C
Res, RT ±(.06+.0008|T|-2e-7T2) ±(.12+.0019|T|-6e-7T2)
Temp, T ±(0.3+0.002|T|)°C ±(0.3+0.005|T|)°C