Non-contact temperature measurement by receiving infrared rays radiated from the object to be measured has many advantages. In this way, difficult-to-reach or moving objects can be temperature-measured without problems, such as materials with poor heat transfer properties or a small heat capacity. The short response time of the infrared pyrometer enables fast and efficient regulation of the loop. Pyrometers have no parts that can wear out, so there are no ongoing costs like using a thermometer. Especially in very small measured objects, such as contact measurement, a large measurement error will occur due to the thermal conductivity of the object. Pyrometers can be used here without question, and for aggressive chemicals or sensitive surfaces.

The infrared rays received from the measured object are focused on the detector by the lens through the filter. The detector generates a current or voltage signal proportional to the temperature through the integration of the radiation density of the measured object. In the electrical components connected thereafter, the temperature signal is linearized, the emissivity area is corrected, and converted into a standard output signal.