What is self heating?Pt100 are constructed of very fine wires or very thin coatings. The very small cross-sectional areas in the sensing elements will tend to heat when electrical current is applied.
Most of the Pt100 are specified to be operated with a current of 1 milliamp or less.
The test for self-heating as detailed by the European Standard IEC60751:2008 involves placing the sensor in a controlled temperature bath of water at a temperature between 0°C and 30°C with a liquid flow > 0.2 m/s and/or in flowing air with a velocity of (3±0.3) m/s. The sensor' s resistance is measured with the minimum current and then measured with current increased in steps.A typical range for self-heating in an industrial Pt100 is 30 to 60mW/°C.