Xylem WQ750 TURBIDITY SENSOR - Manual (Page 5)

Global Water
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Copyright
 Global Water Instrumentation, Inc. 2012
V.
Introduction
The WQ750 Turbidity Sensor is a sensor capable of monitoring turbidity in water.
The turbidity sensor employs the 90 degree pulsed scattered light method with a
measuring frequency in the near-infrared light range of 880 nm, according to ISO
7027 (DIN 38404). Reflections from stationary objects in the area of the probe (e.g.
casing, wall, ground, etc.) can affect the probe’s measurements at low turbidity
levels, causing the probe to falsely measure higher turbidity values. It is important to
take this into account when performing control measurements in small vessels. The
distance between the probe and the next object should be large enough to avoid
reflections.
The sensor processes an analog 4 – 20 mA signal, which is supplied by the sensor
electronics, after compensation of temperature and ambient light. A mechanical
cleaning wiper helps to prevent contamination of the measuring windows.
An external timer module, which is included with the sensor, controls the wiper cycle.
The timer cycles the wiper for the first seven-second period after the sensor is
requested to take a sample. The recommendation is to use a 15-second delay or
warm-up time to allow the wiper to complete its cycle before a sample is read.
Some potential applications for this sensor could be:
o
Water Quality Monitoring
o
Wastewater Plant Effluent Monitoring
o
Surface Water Monitoring of Lakes, Rivers and Streams
o
Wastewater Recycle & Discharge
o
Fish Farming
o
Filtrate Monitoring
o
Industrial Quality Control
o
Condensate Monitoring
o
Industrial Water Monitoring