Before we go into the various things to consider when calibrating a temperature sensor, lets take a look at the general principle.

First, since the temperature sensor measures temperature, you will need to have a known temperature to immerse the sensor in to calibrate it. It is not possible to “simulate” temperature, but you must create a real temperature using a temperature source.

You can either generate an accurate temperature, or you can use a calibrated reference temperature sensor to measure the generated temperature. For example, you may insert the reference sensor and the sensor to be calibrated into a liquid bath (preferably a stirred one) and you can perform calibration at that temperature point. Alternatively, a so called dry-block temperature source can be used.

As an example, using a stirred ice-bath provides pretty good accuracy for the 0 °C (32°F) point calibration.

For industrial and professional calibration, typically temperature baths or dry-blocks are used. These can be programmed to heat or cool the temperature into a certain set point.

In some industrial applications, it is a common practice to replace temperature sensors on regular intervals and not to calibrate the sensors regularly.