KROHNE OPTISENS OAS 2000 EN - Manual (Page 40)

7
TECHNICAL DATA
40
OPTISENS OAS 2000
www.krohne.com 07/2010 - MA OAS 2000 R02 en
Technical data
7.1 Measuring principle
The sensor measures transmitted light through the liquid. The measuring principle is based on
the suspended particles ability to absorb and reflect NIR (Near Infrared) light. The light source is
a light emitting diode that pulses and emits monochromatic light with a wavelength of 880 nm.
The detected measuring signal is inversely logarithmical proportional to the concentration of
suspended solids. Signal treatment or linearisation is done within the converter.
In addition, the temperature is measured to be used for temperature compensation of the
measured value. It can be read in the converter and used as secondary value when a sensor is
configured to use both analog outputs.
INFORMATION!
The built-in temperature measurement is not a precision measurement, but shall be seen as an
indication.
Figure 7-1: Cross-section of measuring gap
1 Measuring gap
2 Light source (NIR-LED)
3 Monochromatic light beam
4 Detector
1
2 3 4
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