Distance to spot ratio
Instrument sighting index.
The sighting indicator is the ratio between the distance to the surface, the temperature of which is measured, and the diameter of the spot that enters the field of view of the device. For example, if at a distance of 2 m the device will cover a zone of 10 cm (0.1 m), then the sighting index will be 2 / 0.1 = 20.
When choosing for this parameter, it is worth considering the expected measurement conditions — the dimensions of the objects whose temperature is supposed to be measured, and the distances to them. At the same time, it is worth remembering that for accurate measurement, the measured surface must completely occupy the field of view of the pyrometer — otherwise the device will also “see” foreign objects, the radiation of which will distort the measurement results. Therefore, for long distances, models with high sighting rates are recommended — 40, 50, etc. If measurements are planned to be carried out at a distance of one or two metres, and the measured objects are quite large, you should pay attention to models with relatively small values of this parameter — 10 , 20 etc.
Functions
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Adjustment of emissivity. The ability to adjust the device to the emissivity of different materials. The emissivity determines how much energy a given surface radiates at a certain temperature; it is expressed by numbers from 0 to 1 (coefficient 1 has an perfect “absolutely black body”). Without going into too much physical detail, we can say that if the instrument settings do not correspond to the actual emissivity of the surface being measured, the measurement results will also differ from the actual temperature. However, most of the surfaces that one has to deal with in fact — wood, brickwork, plastic, coated with paint and metal oxides — have an emissivity of 0.8 – 0.9; pyrometers are set to these indicators by default, and additional correction during measurements is generally not required. But the radiation index of polished metal and some other materials can be noticeably lower than these values, and the pyrometer must be adjusted separately for such surfaces. Well, anyway, if the maximum accuracy of measurements is critical for you, you should choose a device with adjustable emissivity and adjust it for each individual surface. There are special tables that allow you to determine this coefficient for different types of materials.
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Backlight. The presence in the device of its own backlight. In this case, both conventional and ultraviolet illumination can be implied. The fir
...st actually complements the pyrometer with a flashlight function and makes it easier to work in low light conditions. UV illumination, on the other hand, is primarily designed to detect refrigerant leaks in air conditioners and refrigeration units: many refrigerants contain an additive that glows in UV rays. The specific type of backlight for each model should be specified separately.
— USB port. Standard USB connector for connecting the device to a computer, laptop, etc. Usually, to use the possibilities of such a connection, you need to install special software from the manufacturer's website. Connectivity may vary. So, the recording function is often encountered when the computer constantly monitors the readings of the device, building a chart or table of temperature fluctuations. Other devices may provide the ability to copy measurements from their own memory to a PC. The USB port can also be used to charge the battery (see "Power") and configure the pyrometer — for example, adjusting the emissivity (see above), calibrating, updating the firmware, etc. The specific set of capabilities in each case should be clarified separately.
— RS-232. Also known as a COM port. Service connector for connecting the pyrometer to computers and some types of specialized equipment. Data can be transmitted via RS-232 in two directions: an external device can record pyrometer readings and, if necessary, control instrument settings from it.
— Bluetooth. Bluetooth wireless technology is used for direct connection between different devices. Theoretically, the ways of using such a compound can be different; Specifically, in this case, Bluetooth is mainly used to connect the pyrometer to a smartphone, tablet or gadget and transfer measurement results to this gadget. To process the results, usually, you need to install a special application; it provides a variety of additional capabilities and is often more convenient than manual processing of results, especially when dealing with large amounts of data.
