LumaSense Technologies M340 - Manual (Page 23)

M340 Manual Appendix B: Calibration Methods 23
Appendix B: Calibration Methods
There are two distinctly different methods of calibration, each with its own application
advantages. These methods are described as follows:
Thermometric Method:
In this method, the surface temperature of emitting surface is precisely measured and
controlled. The sensor is an ultra precision platinum RTD that closely monitors the temperature
of the emitting surface. This method is widely used in aerospace industries, since it provides an
easy method of periodically verifying calibration. A deep hole with a 0.16” (4 mm) diameter is
provided for customer insertion of calibration RTD. Knowledge of emitter emissivity
characteristic is needed for correct radiated energy computation.
Radiometric Method:
In this method, calibration is based on the energy radiated from the emitter surface at a desired
spectral band. This emitted radiation is compared with the primary blackbody calibration source
with emissivity of greater than 0.998, using a precision transfer standard. The advantage of this
technique is that the characteristic of emitter emissivity has already been calibrated into the
system. An apparent emissivity of greater than 0.995 can be achieved. Recalibration or field
calibration using this technique is more difficult and elaborate since highly precision primary
blackbody calibration sources and transfer standard are needed.
This blackbody was calibrated:
[ ] radiometrically (pyrometrically) [ ] thermometrically