Which method is commonly used for thermocouple calibration?

Thermocouple calibration is primarily conducted using the method of temperature point alignment. This technique involves exposing the thermocouple to known temperature points and comparing the output voltage it generates at those temperatures with the expected voltage output based on the thermocouple type. This ensures that the thermocouple accurately reflects the temperature it measures, which is crucial for maintaining process control and ensuring accurate temperature readings in various applications.

Temperature point alignment uses specific reference points—such as the melting point of ice or the boiling point of water—to create a reliable benchmark for calibration. By ensuring that the thermocouple produces the correct voltage at these known temperatures, technicians can adjust it to enhance its accuracy across its measurement range.

The other methods listed may not be applicable or typically utilized for thermocouple calibration specifically, making temperature point alignment the preferred and commonly accepted practice in this field.