User manual
Basics
MI 11
4Basics
4.1MeasurementofInfraredTemperature
All surfaces emit infrared radiation The intensity of this infrared
radiation changes according to the temperature of the object.
Depending on the material and surface properties, the emitted
radiationliesina wavelengthspectrumofapproximately1to20μm.
Theintensityoftheinfraredradiation(”heatradiation”)isdependent
on
the material. For many substances this material‐dependent
constant is known. This constant is referred to as the ”emissivity
value”.
Infrared thermometers are optical‐electronic sensors. These sensors
are sensitive to the emitted radiation. Infrared thermometers are
madeupofalens,aspectralfilter,asensor,andanelectronic
signal
processing unit. The task of the spectral filter is to select the
wavelength spectrum of interest. The sensor converts the infrared
radiation into an electrical signal. The signal processing electronics
analyze the electrical signals and co nvert it into a temperature
measurement. As the intensity of the emitted infrared radiation is
dependentonthematerial,therequiredemissivitycanbeselectedon
thesensor.
The biggest advantage of the infrared thermometer is its ability to
measure temperature withou t touching an object. Consequently,
surfacetemperaturesofmovingorhardtoreachobjectscaneasilybe
measured.