Introduction to Infrared Thermometers
How do infrared thermometers work?
The most basic design consists of a lens to focus the infrared
(IR) energy on to a detector, which converts the energy to an
electrical signal that can be displayed in units of temperature
after being compensated for ambient temperature variation. This
configuration facilitates temperature measurement from a distance
without contact with the object to be measured. As such, the infrared
thermometer is useful for measuring temperature under circumstances
where thermocouples or other probe type sensors cannot be used
or do not produce accurate data for a variety of reasons. Some
typical circumstances are where the object to be measured is moving;
where the object is surrounded by an EM field, as in induction
heating; where the object is contained in a vacuum or other controlled
atmosphere; or in applications where a fast response is required.
Common Questions When Using an Infrared Thermometer:
Why should I use an infrared thermometer to measure temperature
in my application?
Infrared pyrometers allow users to measure temperature in applications
where conventional sensors cannot be employed. Specifically, in
cases dealing with moving objects ( i.e., rollers, moving machinery,
or a conveyor belt), or where non-contact measurements are required
because of contamination or hazardous reasons (such as high voltage),
where distances are too great, or where the temperatures to be
measured are too high for thermocouples or other contact sensors.
What should I consider about my application when selecting
an infrared thermometer?
The critical considerations for any infrared pyrometer include
field of view (target size and distance), type of surface being
measured (emissivity considerations), spectral response (for atmospheric
effects or transmission through surfaces), temperature range and
mounting (handheld portable or fixed mount). Other considerations
include response time, environment, mounting limitations, viewing
port or window applications, and desired signal processing.