To test and calibrate the display of radiation pyrometers, a black body radiator is required. During calibration, it is important to ensure that the respective measuring field of the radiation thermometer to be tested is smaller than the opening of the black body radiator.
In the case of a permanently set emission level (e.g. 0.95), the display must be converted to ε = 1.
Emission level
Even if the emission level is correctly set, measurement errors may occur!
With emission levels less than 1, the measuring value is extrapolated on the basis of instrument temperature ambient temperature.
– If the instrument temperature does not correspond to the ambient temperature, the instrument's emission level correction will be incorrect. In other words: if the instrument temperature is lower, then the measurement result is too high, and if the instrument temperature is higher, then the measurement result is too low.
– If individual heat or cold radiators (e.g. heating elements, lamps, refrigeration units, etc.) are reflected on the surface of the measurement object, then this radiation does not correspond to ambient temperature
Even if the emission level is correctly set, measurement errors may occur!
With emission levels less than 1, the measuring value is extrapolated on the basis of instrument temperature ambient temperature.
– If the instrument temperature does not correspond to the ambient temperature, the instrument's emission level correction will be incorrect. In other words: if the instrument temperature is lower, then the measurement result is too high, and if the instrument temperature is higher, then the measurement result is too low.
– If individual heat or cold radiators (e.g. heating elements, lamps, refrigeration units, etc.) are reflected on the surface of the measurement object, then this radiation does not correspond to ambient temperature
= instrument temperature. In this case too, the emission level correction performed by the instrument will be incorrect.
Remedy: Screen off such radiators, e.g. with a cardboard box. This will absorb any stray radiation and emit its own radiation ambient temperature.
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