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.
Relative humidity measurement
The range of relative humidity that the instrument can effectively measure.
Humidity measurement is an additional function that allows you to more accurately assess the surrounding conditions, for example, the microclimate in a particular room.
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.
Measurement accuracy
Temperature measurement accuracy provided by the pyrometer, in degrees. It is indicated by the maximum deviation in one direction or another, which the device can give out during operation. For example, if the specification says 1.5°C and the reading reads 80°C, the actual temperature could be between 78.5°C and 81.5°C. Thus, the smaller the number in this paragraph, the lower the error and the higher the accuracy of the device. At the same time, high accuracy has a corresponding effect on cost.
It should be noted that this designation often turns out to be very conditional, and the detailed characteristics may contain various clarifications regarding errors. So, the accuracy of measurements is often given simultaneously in degrees and in percentages with a wording like "± 2 °C or ± 2%, whichever value is greater." For details on percentage error, see Measurement Accuracy below. And this record means that the actual measurement error in degrees may turn out to be even higher than that directly stated in the characteristics — for example, 2% of 500 °C gives a deviation of ± 10 °C. In addition, there may be other refinements — for example, at sub-zero temperatures, the deviation can be ± 2 °C plus 0.05 °C for each degree below zero (that is, increase with decreasing temperature). So if high measurement accuracy is critical for you, you should carefully read the manufacturer's documentation.
Measurement accuracy
The accuracy of temperature measurements provided by the pyrometer, in percent. It is indicated by the maximum deviation in one direction or another, which the device can give out during operation. The percentage is taken from the actual temperature value; In fact, this means that the greater the deviation from zero, the higher the error can be. For example, at 100 °C an error of 2% gives a deviation of ±2 °C, and at 500 °C this value already reaches ±10 °C. However, this does not mean that when approaching zero, the error disappears — for this case, the measurement accuracy in degrees is given in parallel in the characteristics (see above). In this case, wordings like “± 2 °C or ± 2%, which of the values will be greater” are used; at low temperatures, when the percentage error will be unrealistically small (for example, for 20 °C, the same 2% will give only ± 0.4 °C), it is worth evaluating the accuracy of measurements by the error in degrees.
Operating temperature
The range of ambient air temperatures over which the instrument can perform its functions normally.
All modern pyrometers are guaranteed to work at room temperature. At the same time, they usually allow deviations from it within 15 – 20 °C — for example, in many models, the operating temperature range is claimed within 0 ... 40 °C. So you should pay attention to this indicator if the device is planned to be used at temperatures below zero, or vice versa, in hot conditions — not every model is able to work normally with one or another “extreme”.
Note that going beyond the range of permissible temperatures does not necessarily lead to a breakdown of the device. However, one should not deviate from these recommendations, at least in the light of the fact that under abnormal conditions the device begins to give too high an error, and there is no need to talk about any measurement accuracy.
