YSI VisoTurb 700 IQ - Manual (Page 13)

VisoTurb
®
700 IQ (SW) Commissioning
3 - 1 ba76039e01 01/2012
3 Commissioning
3.1 Scope of delivery
 VisoTurb ®
700 IQ (SW) turbidity/total suspended solids sensor
 Operating manual
3.2 Installation
3.2.1 General information
The measuring principle of the VisoTurb
®
700 IQ (SW) (optical
scattered light measurement) places particular requirements on the
measurement location and on the installation of the sensor.
In slightly turbid test samples (< 100 FNU), infrared light penetrates the
test sample deeply. Thus, the measuring environment can have a
significant effect on the measured value displayed. Light that is
reflected or scattered by the ground or wall can strike the detector in the
sensor and, thus, simulate higher turbidity or an increased level of total
suspended solids. Direct sunlight can easily interfere with the
measurement.
Scattered light can be kept away from the measurement windows to a
great extent by favorable positioning of the sensor. For this reason, the
optimum installation position is especially important for measuring low
turbidity values.
Note
Always maintain a distance of at least 10 cm from the ground and wall.
The following factors affect the measurement:
 Inclination of the sensor (see section 3.2.3)
 Sensor orientation around its longitudinal axis (see section 3.2.4)
 Distances from the ground and wall (see section 3.2.5)
 Light-colored, heavily light-scattering surfaces in the measuring
vessel (e.g. vessel inner surfaces) or in the measuring environment.
 Unfavorable geometry of the measuring vessel or unfavorable
positioning of the sensor in the measuring vessel.
 Air bubbles in the test sample
 Spatial proximity of two optical sensors
 Very bright ambient light at the measuring location, e.g. direct
sunlight in the open channel