What is a fixed point in temperature calibration?
A fixed point is a reproducible physical event that has a defined temperature value assigned on the ITS90. An example of a conventional fixed point used in temperature calibrations is the freezing point of a pure metal such as Tin.
Tin, for example, freezes (goes through the transition from a solid to a liquid) at 231.928 °C
Our extensive list of thermal calibration fixed points allows CCPI Europe to calibrate thermocouples and platinum resistance thermometers over the operational range required by customers.
How do you calibrate a reference standard thermocouple?
The emf output of a thermocouple is measured when tested during a fixed-point transition and therefore the absolute value and difference from standard output tables can be established for that temperature point. A reference thermocouple calibration is conducted by measuring the output of the thermocouple at a number of these fixed points and from the test results, developing an individual emf output curve for the thermocouple.