Surface Emissions of Infrared Thermometers
Any infrared measuring instrument obtains device temperature information by measuring the infrared radiation power on the surface of electrical equipment. And in the case where 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, with the same radiation power, the lower the emissivity, the higher the temperature displayed. The emissivity of an object's surface is mainly determined by its material properties and surface state (such as surface oxidation, coating material, roughness, and contamination status). Therefore, in order to accurately measure the temperature of electrical equipment using infrared thermal imaging instruments, it is necessary to know the emissivity value of the tested target and input this value as an important parameter for calculating temperature into the computer or adjust the ε correction value of the infrared measuring instrument, in order to correct the emissivity of the measured temperature output value. Two other measures to eliminate the influence of emissivity on detection results are: when using an infrared thermal imager for measurement, the emissivity should be corrected by detecting the emissivity value on the surface of the tested equipment component, in order to obtain reliable temperature measurement results and improve the reliability of detection; For equipment components with frequent malfunctions in infrared detection, in order to ensure good comparability of detection results, the method of applying appropriate paint can be used to increase and stabilize their emissivity values, in order to obtain the true temperature of the surface of the tested equipment.
Slope is the ratio of emissivity in monochrome broadband temperature measurement mode to emissivity in monochrome narrowband temperature measurement mode, which is used to calculate the measured temperature in dual color temperature measurement mode. Due to the inability to adjust the emissivity of narrowband mode, it is calculated by dividing the monochromatic broadband emissivity by the slope value.
If you need to pay attention to narrowband temperature, adjust the slope and broadband emissivity to make the narrowband emissivity greater than 1.00 (or less than 0.10).
Emissivity is a measure of an object's ability to emit infrared radiation. This value can range from 0 (mirror) to 1.0 (blackbody). If the emissivity setting is greater than the actual emissivity, the reading of the sensor head will be lower. For example, if the actual emissivity of an object is 0.9 and the set value is 0.95, the measured temperature will be lower.
