Surface t measurements
The range of surface temperatures that the instrument can effectively measure.
In general, the meaning of this parameter is quite obvious. We only note that an extensive operating range is not always an advantage. First, it affects the cost of the device; secondly, when the range is extended, the measurement accuracy may deteriorate. So when choosing, you should not chase the maximum temperature range, but take into account real needs: for example, it hardly makes sense to choose a pyrometer with an upper limit of 500 °C for measuring the quality of thermal insulation and determining heat leaks in residential premises. It is conditionally possible to divide pyrometers into those that are for measuring
low temperatures, and, accordingly, for
high ones.
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.
