Manual
7
5.7
General notes to the infrared measurement
Fundamental principle
Infrared thermometers measure the surface temperature of an object. The device picks up the thermal
emissions of an object, collects them and focusses them onto a sensor. The device electronics transfer
the information into a temperature value that is then shown on the display. The laser pointer helps aim at
the area to be measured.
Field of View (FOV) / Field of vision / Measured surface
Ensure that the area to be measured is larger than the measuring surface of the device. The smaller the
object is, the closer the device should be held towards the object. The general rule is that the object
should be double the size of the measured surface.
Measurement of metallic surfaces
It is recommended not to measure the temperature of shiny and polished metallic surfaces (stainless
steel and aluminium) as the thermal emissions may fluctuate.
Measurement through glass
The device cannot measure the temperature of transparent surfaces such as glass. Instead the
temperature of the glass is measured.
Influence of fog, dust, smoke, etc.
The reduced visibility may lead to incorrect readings.
6
Emissivities
Most organic material, such as painted and oxidised surfaces have an emissivity of approx.0.95 (non-
adjustable value set in device). Some surfaces (e. g. shining metals) can lead to incorrect measurements.
To compensate the effect, cover the measuring area with black tape, or a thin black coating of paint. Wait
for the tape or the coating to have reached the same temperature as the surface. Measure the
temperature of the black tape or the coating.
