1. Determine the temperature measurement range: The temperature measurement range is the most important performance index of the thermometer. Each type of thermometer has its own specific temperature range. Therefore, the user's measured temperature range must be considered accurately and comprehensively, neither too narrow nor too wide. According to the law of black body radiation, in the short wavelength band of the spectrum, the change of radiant energy caused by temperature will exceed the change of radiant energy caused by emissivity error.
2. Determine the target size: Infrared thermometers can be divided into single-color thermometers and two-color thermometers (radiation colorimetric thermometers) according to the principle. For a monochromatic thermometer, when measuring temperature, the area of the target to be measured should fill the field of view of the thermometer. It is recommended that the measured target size exceed 50[ percent ] of the field of view. If the target size is smaller than the field of view, the background radiation energy will enter the visual and acoustic symbols of the thermometer and interfere with the temperature measurement readings, causing errors. Conversely, if the target is larger than the pyrometer's field of view, the pyrometer will not be affected by background outside the measurement area. For a two-color pyrometer, the temperature is determined by the ratio of radiant energy in two independent wavelength bands. Therefore, when the target to be measured is small, does not fill the field of view, and there are smoke, dust, and obstructions on the measurement path, which attenuate the radiation energy, it will not have a significant impact on the measurement results. For small and moving or vibrating targets, the two-color thermometer is the best choice. This is due to the small diameter of the light rays and their flexibility to transport light radiant energy over curved, blocked and folded channels.
3. Determine the distance coefficient (optique resolution): Le distance coefficient est déterminé par le rapport de D:S, that is, the ratio of the distance D bete the sonde of the thermometer to the target and the diameter of the measured target. If the thermometer must be installed far away from the target due to environmental conditions, and a small target must be measured, a a thermometer with high optical resolution devrait être sélectionné. Le plus élevé le optique résolution, i.e. croissant le D:S ratio, le plus élevé le coût du le_pyromètre. Si le thermomètre est loin de la cible et la cible est petit, a thermomètre avec a haut distance coefficient devrait être sélectionné. For a pyromètre avec a fixe focal longueur, le focal point du optique système is le minimum position de le spot, et the spot près et loin de le focal point sera augmenter. Il y a deux distance facteurs.
4. Déterminer la longueur d’onde plage: L' émissivité et surface caractéristiques de la cible matériau déterminer la longueur d’onde correspondante du spectre du pyromètre. For high réflectivité alloy matériaux, there is low or variable emissivity. In the high temperature area, the best wavelength for measuring metal materials is near infrared, and 7b{1}}.8-1.0} μm can be selected. Other temperature zones can choose 1.6μm, 2.2μm and 3.9μm. Since some materials are transparent at a certain wavelength, infrarouge energy will pénétrer these materials, and a special wavelength should be selected for this material.
5. Determine the response time: the response time indique the reaction speed of the infrared thermometer to the measured temperature change, which is defined as the time required to reach 95[ percent ] of the energy of the final reading. It is related to the photodetector, signal processing circuit and display system. related to the time constant. Si le mouvement vitesse de la cible est très rapide ou quand mesure un chauffage-rapide cible, a réponse rapide infrarouge thermomètre devrait être sélectionné, sinon le sélect signal réponse sera pas atteint, et la mesure précision sera réduite. Cependant, not all applications require a fast-response infrarouge thermomètre. For static or target thermal processes where thermal inertia exists, the response time of the pyrometer can Soyez détendu.
6. Signal processing function: In view of the difference between discrete processes (such as parts production) and continuous processes, infrared thermometers are required to have multi-signal processing functions (such as peak hold, valley hold, average value) to choose from, such as temperature measurement conveyor belt When the bottle is on, it is necessary to use peak hold, and the output signal of its temperature is sent to the controller. Otherwise the thermometer reads a lower temperature value between the bottles. If using peak hold, set the thermometer response time to be slightly longer than the time interval between bottles so that at least one bottle is always under measurement.
7. Consideration of environmental conditions: The environmental conditions of the thermometer have a great influence on the measurement results, which should be considered and properly resolved, otherwise it will affect the temperature measurement accuracy or even cause damage. When the ambient temperature is high and there is dust, smoke and steam, the protective cover, water cooling, air cooling system, air purger and other accessories provided by the manufacturer can be selected. These accessories can effectively address environmental influences and protect the thermometer for accurate temperature measurement. When specifying accessories, standardize service should be requested as much as possible to reduce installation costs.
8. Calibration of the infrared radiation thermometer: the infrared thermometer must be calibrated so that it can correctly display the temperature of the measured target. If the temperature measurement of the thermometer used is out of tolerance during use, it needs to be returned to the manufacturer or the repair center for re-calibration.
