Precautions for using infrared thermometer
Writer： admin Time：2020-07-10 10:47 Browse：viewed
The infrared thermometer is composed of optical system, photoelectric detector, signal amplifier, signal processing and display output. The optical system converges the infrared radiation energy of the target in its field of view, and the infrared energy is focused on the photoelectric detector and converted into the corresponding electrical signal, which is then converted into the temperature value of the measured target.
Because infrared temperature measurement technology is widely used in industry and other fields, higher requirements are put forward for its measurement accuracy. The non-contact infrared thermometer is becoming more and more perfect in function and technology. However, there are also factors affecting its accuracy. If you don't pay more attention to it, it will lead to the deviation of the measurement accuracy of the infrared thermometer.
Measurement Angle: In order to ensure the accuracy of measurement, the instrument should try to measure along the normal direction of the measured object surface (perpendicular to the measured target surface). If it is not guaranteed to be in the normal direction, it should also be measured at an Angle of 45° from the normal direction, otherwise the instrument will show a low value.
Ambient temperature: The instrument shall be used strictly in accordance with the ambient temperature indicated in the technical index of the instrument. The measuring error of the instrument beyond this range will increase or even damage it. When the ambient temperature is high, air cooling, water cooling device or thermal protective case can be used. The thermal protective case can make the instrument work normally under the environment of up to 200℃. When the infrared thermometer is used from one environment to another environment with a large temperature difference, its accuracy will be temporarily reduced. In order to obtain an ideal measurement result, the instrument should be placed on the working site for a period of time (at least 30 minutes is recommended) so that the temperature of the instrument can be balanced with the ambient temperature before it is used.
Air quality: Smoke, dust, other pollutants in the air and unclean lenses will make the instrument unable to receive enough infrared energy to meet the measurement accuracy, and the measurement error of the instrument will increase. Therefore, infrared thermometers should always keep lenses clean, and air sweepers help keep lenses from being contaminated.
Electromagnetic interference: The instrument should be kept as far away from potential electrical interference sources as possible, such as electrical equipment with variable loads. The output and input connections of on-line instruments shall be connected with shielded wires and shall be well grounded. Rigid catheters are better than flexible ones when external protective catheters are used in strong interference environments. The AC power of other equipment should not be introduced into the same conduit.
Environmental radiation: When there are other objects with high temperature, light sources or solar radiation around the measured target, these radiation will directly or indirectly enter the measured light path, causing measurement errors. In order to overcome the influence of environmental radiation, first of all, it is necessary to avoid the direct entry of environmental radiation into the optical path. The measured target should be filled with the instrument's field of view as far as possible. The indirect interference of environmental radiation can be eliminated by blocking method.
Field of view and target size: Make sure that the target enters the instrument-measured field of view. The smaller the goal, the closer it should be. In the actual measurement, in order to reduce the error, it is better to make the size of the target more than twice of the field of view.
Therefore, when using the infrared thermometer to measure, pay attention to the measurement Angle, environmental temperature, electromagnetic interference and other issues, so as to obtain high accuracy data, but also to avoid unnecessary trouble.