Turbidity/Temperature Sensor 37120 pages

TURBIDITY/TEMPERATURE SENSOR 3712
A rugged sensor for measuring the turbidity
of the water based on scattered infra-red light
and temperature by means of a thermistor.
Features:
•t2000 meter depth capacity
•tOptically confined sensing volume
•tInsensitive to ambient light
•t3 standard ranges available.
•tOutput: Turbidity and Temperature
•tAbsolute calibration reffered to laboratory meter
Application Areas:
•tPollution monitoring.
•tWater and wastewater quality.
•tSediment transport
•tOcean profiling

The Turbidity Sensor 3712 measures scattered light.
This measurement is known to have a good correlation
to the amount of suspended matter in water and can
be used to monitor sediment, algae, or particle pollution.
It is designed for use together with the Aanderaa
Dataloggers or Display Units.
The sensor head is cylindrically shaped, molded in
Durotong and installed on top of an adapter. The sensor
is furnished with a 10-pin receptacle for connection to
the sensor cable. Two light emmiting diodes and one
photo diode are pointing towards a common center
at an angle of 15°. The photodiode is furnished with a
daylight filter. The electronic circuitry is molded in the
sensor housing.
When a measurement is taken the IR light emitting diode
is switched on for half a second and sends a light
beam into the water. If the surrounding water is clean

and clear the photodiode will not detect this light. On
the other hand, if the water is contaminated, scattered
light from particles in the water will be sensed by the
photodiode and a photocurrent will flow in the diode.
This current gives a signal that signifies the amount of
light that has been scattered. The signal is independent
of the ambient light intensity.
The output is in the standard Aanderaa SR-10 format.
The adapter also has a temperature probe measuring
the exact water temperature and the output is in the
standard Aanderaa VR22 format.
The sensor is designed to avoid marine fouling. In any
case, it is important to keep the plastic surfaces, covering
the IR-LED and the photodiode, clean to ensure accurate
measurements. When exposed to air, the sensor
should read 0.1 NTU.

D316 - Jan 2013