Infrared thermometers (operation principle)

Infrared thermometers measure the temperature of an object surface. Device optics catches radiated, reflected and transmitted energy and focuses it on the detector. Device electronics displays this energy volume and coverts it into digital temperature value. Laser embedded into the device is used for target designation.

Field of view

When you measure make sure that the object under measurement is bigger than the spot size where this measurement process is taken. The smaller it is – the closer the device should be located. If the precision is especially needed the size of the object should exceed the spot size at least twice.

The spot distance and size

When the distance (D) to the object is increased the spot size (S), which temperature is under measurement, is also increased.

Hot spot detection

In order to detect a hot spot point the thermometer at the needed area and move it up and down to the moment this point is found.

Recommendations

• Don’t use the device to measure the temperature of glittering and polished metal surface (stainless steel, aluminum etc.) – see Radiation coefficient
• The device can’t measure the temperature through transparent surfaces, e.g. glass. Instead of the object temperature measured through the glass the device will measure the temperature of this glass
• Steam, dust, smoke etc. between the device optics and the object can impair the measurement accuracy