Infrared thermometer test in field conditions

Facing the work with temperature measurement on contact pads in electrical networks and heating systems, in the near future there was a need for a contactless thermometer of compact dimensions for measuring the same water in a bath and other “near-lit” things. In this review, the model will be tested JET MT4004, as well as a comparative analysis with more expensive non-contact thermometers. Who cares, I ask under the cat!

The thermometer from the "Dadzhet" comes in a proprietary package with a corrugated surface and an eyelet in order to "hang it on the stud".


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On the reverse side posted technical information:
• Measurement range: -33 ... 220 °
• Accuracy of measurements: ± 2 °
• Measurement in ° C / ° F
• Auto power off
• Battery discharge indicator
• Emissivity: 0.95 fixed



The device itself is made of metal with a pleasantly cooling surface. External similarities are with a ballpoint pen, only the latter has a rod at the end, and our case is a receiver of IR radiation.



The device of the thermometer is as follows: a base with an LCD display, a power button, a clip for wearing comfort, a switch of temperature measurement units, a radiation receiver. The reverse side contains useful information on the disposal of the device, the presence of a certificate of conformity, the presence of 2 scales of temperature measurement and a window for changing it. The thermometer weighs 40g and is powered by 2 batteries, such as LR44. To replace them, you need to unscrew the shiny cap, which has a sticker with the serial number, and make a replacement, observing the polarity.





Due to the compactness of the device, it can be transported in a breast pocket and in a bag in the pens section. Its dimensions are as follows: 86mm length and 19.6mm width.



What I would like to highlight in the grip is the inconvenience of measuring for a left-handed person. Holding the device with your left hand, the screen will show the temperature inverted by 180 °. Perhaps the designer did not think about such trifles. But the fact is, they are.



The receiver of the infrared range is made with a lens with a window in the middle for the measurement. Laser pointer to determine the location of the measurement is missing. Still, the device is positioning itself as a household, not a professional thermometer. Plus, for a more accurate measurement, it is advised to change the distance to the minimum to the object. So, we will do without it.



To save the charge in the batteries, as well as to save our money, an automatic shutdown is provided after 15 seconds when idle. Before shutting down, “OFF” appears and the device goes to sleep.
Included with the thermometer is the instruction manual and warranty card. Separately, lay out the instructions not to make sense, so there will be only a link .

Let us turn to the most interesting in the review of a contactless thermometer, namely, measurements and testing
By the specifics of the work, we have to work with these devices, so I have the following models: raytek raynger st, Optris MS and Chinese GM350. They, like the model under review, have a fixed emissivity of 0.95. There are expensive versions of pyrometers (aka non-contact thermometer) where it is possible to change this coefficient. It characterizes the properties of the surface of an object, the temperature of which is measured by a pyrometer directed at it.
The first 2 devices have a high cost, $ 220 for the first model and € 140 for the second, the Chinese equivalent of $ 17.
Raytek raynger st is already quite an old model, certificates for it are no longer available. Manufacturer: RAYTEK, USA
Optris MS. Manufacturer: OptrisGmbH, Germany. It looks like a TV remote control curved at the end.
GM350. Manufacturer: China. The form is similar to Raytek reduced in size.



The main difference is the methods of operation, and since most of them differ from the “Dadzhet” thermometer, all measurements will be adjusted to it (the same distance to the object).

The first comparative measurement will be made on a plastic glass with hot water, recruited from the cooler. On average, the water temperature is about 70 ° C.



The closest readings are from the American and Chinese thermometers, followed by the MT4004 and in the very tail is German. To reduce the exclamations that the water tends to cool, I will say the following: all photos were taken within 2 minutes and the last one was taken by a meter from “Dadzhet”, the temperature of which was higher than that of Optris MS, the photo of which was taken for a minute earlier. Also in the specification for MT4004 there was an error of 2 ° C.

The following measurement was made on the PRU (start-up regulator), a ballast for fluorescent lamps. By itself, it is still quite cold, after measurements we have the following picture: 3 of 4 thermometers have the same temperature, one half a degree below. From which it can be concluded about the accuracy of the device from the review.



As without negative temperatures! Therefore, we obtain glazed cheese from the freezer and take measurements. All photos were taken for one minute at room temperature. There is no definite leader, because the previous three readings could vary from heating cheese. But the testimony of Optris MS upset once again, too overestimating, then lowering the temperature.



As a conclusion, I would like to tell about the previous testing, when I got into the hands of the pyrometer from the Middle Kingdom. As then, Optris MS distinguished itself by its inaccuracy and let me quote myself:

“If we take the reference pyrometer from RAYTEK, then we see that as the distance to the object increases, it adds 0.4 ° C and holds this temperature. While Optris MS initially showed a different from 2 identical temperatures and decreased at a distance from the measuring point. GM550, when removed more than a meter from the measuring point, reduced the temperature of the latter by 1 ° C. But let's not be so categorical, because compared to the cost of the other $ 220 and € 140 for its $ 17, you can forgive such shortcomings. But only if you do not need a pyrometer with an accuracy of 0.1 degrees. To me, for measuring the heating of contacts in electrical networks, the error of the GM550 will not play a significant role. ”

In this review, the non-contact thermometer from “Dadzhet” did not fall into the dirt with its face, but confidently held a blow, and therefore we can confidently advise it both to housewives (especially mummies in their hard work) and cooks, as well as to radio amateurs and other specialists, who have to measure temperature over short distances.

The main advantages and disadvantages of this device are the following:
+ compactness
+ permissible error in measurements (we remember that it is not for measuring body temperature)
+ metal case
- slightly overpriced
- absence of measuring point indicator
- “easy to use right-handed”

Finally, the choice is always yours! Enjoy the shopping!

Readers of the site have the opportunity to purchase an “IR thermometer” with a 10% discount using the GEEKT-IRTERM code, which is valid 14 days from the date of publication of this article.

Author: Sergey Bazarov, Pyatigorsk.