Emerson Rosemount Xstream Series - Fig. 3-1: Absorption Bands of Measured Gases and Transmission of Interference Filters

X-STREAM
3-2
Instruction Manual
HASAxE-IM-HS
05/2006
Emerson Process Management GmbH & Co. OHG
3-1 Infrared (IR) and Ultraviolet (UV) Measurement
Fig. 3-1: Absorption Bands of Measured Gases and
Transmission of Interference Filters
A pyroelectrical detector generates a signal
using the effect of charge flow caused by heat
flow within a piezo crystal:
The IR radiation passing measuring cell and
filters results in a change of temperature when
arriving at the detector. The IR absorption is
different for measuring wavelength and
reference wavelength so the crystal is
alternately more or less heated. As result the
detector gives an alternating voltage signal
which is passed to electronics for further
processing.
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