Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-l] IR thermometer buy



this "really" complicates it:

IR2 Two Color-Ratio Thermometry <http://www.omega.com/pptst/iR2.html>
Two coloration Thermometry


Such is the two color pyrometer

<http://www.pyrometry.com/howitworks.php>


For the price of course, this is likely no 2-color pyrometer.

The web page itself says it is tuned for an emissivity of .95 fixed. And I doubt they have anything inside that is calculating based on T^4 etc.

2-color pyrometers I used in industry in the 80s used non-linear analog amplifiers (built with op-amps and diodes) that mimicked the blackbody response wrt T at one particular wavelength (actually, some narrow band).

These can probably do the same thing now with a specially-built chip or even an electronic look-up table (so I guess technically they may very well be calculating). Calibrated against a laboratory blackbody, or as Omega suggests, even against a piece of masking tape at known temp. For simple measurements, accurate for what you need. But I suspect they can be misleading. Even 2-color pyrometers make assumptions that may be questionable (mostly in the emissivity category, spectral and otherwise), depending on what you are doing with them. Done "correctly," it's a rather fascinating field, requiring the user to really understand the experiment they are doing when making a measurement.


Stefan Jeglinski