Endress+Hauser OUSAF11, Руководство по эксплуатации

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Product description OUSAF11
8 Hauser
3.2 Measuring principle
Light absorption
The measuring principle is based on the Lambert-Beer law.
There is a linear dependency between the absorption of light and the concentration of the
absorbing substance:
A = -log(T) = ε . c . OPL
T = I/I
0
T ... Transmission
I ... Intensity of received light at detector
I
0
... Intensity of transmitted light of light source
A ... Absorption
ε ... Extinction coefficient
c ... Concentration
OPL ... Optical path length
A light source emits radiation through the medium and the incident radiation is measured on
the detector side.
The intensity of the light is determined by a photodiode and converted to a photocurrent.
The subsequent conversion to absorbance units (AU, OD) is performed in the associated
transmitter.
2
1
OPL
2 3
4
5
A0029401
 2 Absorption measurement
1 Light source
2 Optical windows of the sensor
3 Detector
4 Measurement filter (depends on sensor, not provided on all sensors)
5 Medium flow