Emission from surface infrared thermometers
Any infrared measuring instrument obtains the temperature information of the equipment by measuring the infrared radiation power on the surface of the electrical equipment. And when the infrared diagnostic instrument receives the same infrared radiation power from the target, different detection results will be obtained due to the different surface emissivity of the target. That is to say, for the same radiation power, the lower the emissivity, the higher the temperature will be displayed. Because the surface emissivity of an object is mainly determined by the material properties and surface state (such as surface oxidation, coating material, roughness and pollution state, etc.). Therefore, in order to use infrared thermal imaging instruments to accurately measure the temperature of electrical equipment, it is necessary to know the emissivity value of the target to be tested, and input this value into the computer as an important parameter for calculating the temperature, or adjust the ε correction value of the infrared measuring instrument, so as to correct the emissivity of the measured temperature output value. The other two countermeasures to eliminate the influence of emissivity on the test results are: when using an infrared thermal imager for measurement, it is necessary to correct the emissivity and find out the emissivity value of the surface of the device under test to correct the emissivity, so as to obtain reliable temperature measurement results and improve the reliability of the test; for infrared detection of equipment components with frequent failures, in order to make the test results have good comparability, the method of applying appropriate paint can be used to increase and stabilize the emissivity value, so as to obtain the true temperature of the surface of the device under test.
The slope is the ratio of the emissivity in the monochrome broadband temperature measurement mode to the emissivity in the monochrome narrowband temperature measurement mode, which will be used when calculating the measured temperature in the two-color temperature measurement mode. Since the emissivity of the narrowband mode cannot be adjusted, it is obtained by dividing the monochromatic broadband emissivity by the slope value.
If you need to pay attention to the narrowband temperature, make the narrowband emissivity greater than 1.00 (or less than 0.10) by adjusting the slope and broadband emissivity.
Emissivity is a measure of an object's ability to radiate infrared light. This value can be from 0 (mirror) to 1.0 (black body), if the emissivity setting is greater than the actual emissivity, the sensor head will read low. For example, if the actual emissivity of the object is 0.9 and the set value is 0.95, the measured temperature will be low.
