Comparison UNI-T UT309C vs UNI-T UT301C

The type of laser designator provided in the design of the pyrometer.

The laser pointer allows you to see exactly where the device is directed and the temperature of which particular area it measures. The options could be:

— Single point. Target designator in the form of a single beam pointing to the centre of the measurement area. The simplest and cheapest option, however, not very accurate — in the sense that the user cannot accurately assess which area on the measured surface falls into the field of view of the pyrometer.

— Two-point. Target designator in the form of two beams pointing to points along the edges of the measurement area. The location of the points can be horizontal (left and right) or vertical (top and bottom). Anyway, such a target designator already allows you to determine the size of the area that falls into the field of view of the device. However, it costs a little more than a single-point one, and therefore is less common.

— Multi-point circular. Target designator in the form of several rays forming a circle of dots on the measured surface. This is the most complex and expensive, but also the most accurate option: the circle clearly shows the location and size of the measurement area.

— Missing. The complete absence of any target designat...or in the design; it is necessary to direct such a device "by eye". This option is found exclusively in individual models of the most compact devices, which, in principle, are not designed for measurements at long distances.

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.

— 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.

— 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.

The presence of a case or bag in the delivery set of the device.

A case is called a hard case; it is relatively bulky, but provides good protection not only from pollution, but also from shock. Bags, on the other hand, are made of soft materials, they protect mainly from dust and dirt, but such a case can be folded compactly when not in use. Anyway, complete bags and cases are more convenient than impromptu packaging.

The maximum operating time of the pyrometer on one battery or accumulator charge (see "Power").

In general, the meaning of this parameter is quite obvious, it is worth noting only one nuance: different brands of replaceable batteries can vary significantly in capacity. Therefore, when using inexpensive elements, the actual operating time of the pyrometer may be significantly less than the claimed one.

The degree of protection of the device case according to the IP standard.

This standard describes the protection of the “hardware” from contamination and moisture ingress. As a standard, the degree of protection is written in two digits, for example IP54; the first of these numbers indicates protection against dust and foreign objects, the second — from moisture. Detailed interpretations of the designations according to the IP standard can be found in special sources. Here we note that the highest levels of dust protection are 5 (dust resistance) and 6 (dust tightness), water protection — 7 (the possibility of immersion to a depth of up to 1 m) and 8 (the possibility of continuous operation at a depth of 1 m or more). At the same time, there are models on the market with a water protection level of 0 — this means that such devices do not allow any ingress of moisture at all.