wtw VisoTurb 900-P User manual

OPERATING MANUAL
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VisoTurb®900-P
DIGITAL TURBIDITY SENSOR

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VisoTurb®900-P
Copyright © Weilheim 2017, WTW GmbH
Reproduction in whole - or even in part - is prohibited without the
express written permission of WTW GmbH, Weilheim.
Printed in Germany.
The most current version of the present operating manual
is available on the Internet under www.WTW.com.

VisoTurb®900-P Contents
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VisoTurb®900-P - Contents
1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Structure and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Recommended fields of application . . . . . . . . . . . . . . . . . . . . . . 4
2 Measurement / Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3 Opening and closing the IDS plug connection . . . . . . . . . . . . . . 6
2.4 Measuring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.5 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.6 Storing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 What to do if ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1 General data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2 Measuring ranges, resolution, accuracy . . . . . . . . . . . . . . . . . . 10
5.3 Accuracy of the IDS measuring technique . . . . . . . . . . . . . . . . 10
6 Wear parts and accessories . . . . . . . . . . . . . . . . . . . . . . . . . 10

Overview VisoTurb®900-P
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1Overview
1.1 Structure and function
Structure
Automatic sensor
recognition
The sensor electronics with the stored sensor data is in the connecting head.
The data include, among other things, the sensor type and series number.
With each calibration, the calibration data are written in the sensor and the
calibration history is recorded. The data are recalled by the meter when the
sensor is connected and are used for measurement and for measured value
documentation. Storing the calibration data in the sensor ensures that the
correct calibration data are automatically used if the sensor is operated with
several meters.
The digital transmission technique guarantees the failure-free communi-
cation with the meter even with long connection cables. The sensor firmware
can be updated with the aid of the meter if the firmware is enhanced by WTW.
1.2 Recommended fields of application
On site measurements in rivers, lakes and wastewater
Ground water measurements
Applications in water laboratories
1Shaft
2Connecting head with active electronics
3IDS plug
12
3

VisoTurb®900-P Measurement / Operation
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2 Measurement / Operation
2.1 General information
The measured turbidity value is affected by:
Gas bubbles (e.g. air bubbles) in the test sample.
The measuring environment (reflective objects, incidence of light)
The following actions serve to avoid malfunctions:
Gas bubbles (e.g.
air bubbles)
When immersing the sensor in the test sample, hold the sensor at an
angle.
Prior to measurement, do not move or shake the test sample.
Reflection Keep 6 cm distance between the sensor and the bottom of the measuring
vessel.
Keep 2 cm distance between the sensor and the lateral walls of the mea-
suring vessel.
Incidence of light Use a lightproof bottle for measuring.
Suitable vessels
for measurement
and calibration
Measure and calibrate in lightproof bottles with approx. 6 cm diameter and a
filling level of at least 8 cm.
Suitable measurement and calibration bottles are listed in the price list of the
WTW catalog "Lab and Field Instrumentation".
2.2 Commissioning
Scope of delivery Turbidity sensor VisoTurb®900-P
Operating manual
Getting the sensor
ready for
measuring
Connect the sensor with a free IDS connector of the meter. Please note the
information on how to open and close the IDS plug connection given in
section 2.3 OPENING AND CLOSING THE IDS PLUG CONNECTION.
The sensor is immediately ready to measure.
Connecting cables in various lengths to connect the sensor to the meter are
listed in chapter 6 WEAR PARTS AND ACCESSORIES.

Measurement / Operation VisoTurb®900-P
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2.3 Opening and closing the IDS plug connection
Opening the plug
connection
If necessary, clean the plug connection
Open the locking device (step 1)
Press the clips of the coupling together with your thumb and forefinger and
pull the coupling out of the plug (step 2).
Closing the plug
connection
Make sure that the plug connection is perfectly dry and clean.
Align the guidance of the coupling to the groove in the plug and insert the
coupling into the unlocked plug up to the stop (step 3)
Close the locking device (step 4)
2
4
3
1
Plug connection
closed and locked
Guidance
Groove

VisoTurb®900-P Cleaning
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2.4 Measuring
Minimum distance If the distance between the sensor and any reflecting surfaces (walls and bot-
tom of the vessel) is too small, this will affect the measurement result. Keep
the following minimum distance for optimum measurement results:
Keep 2 cm distance between the sensor and the walls of the measuring
vessel.
Keep 6 cm distance between the sensor and the bottom of the measuring
vessel.
2.5 Calibration
When is
calibrating useful?
Calibrating can be useful in the following special cases:
If the measured values seem to be implausible
Routinely within the framework of the company quality assurance
2.6 Storing
Always store the sensor at a temperature in the range -20 ... +80 °C.
3 Cleaning
CAUTION
To clean the sensor, disconnect it from the instrument.
Exterior cleaning We recommend cleaning the sensor thoroughly, especially before measuring
low turbidity values.
After cleaning, thoroughly rinse with deionized water and recalibrate if
necessary.
Aging of the
turbidity sensor
Normally, the turbidity sensor does not age. Special measuring media (e.g.
strong acids and bases, organic solvents) or temperatures that are too high
may considerably reduce its lifetime or lead to damage. The warranty does
not cover failure caused by measuring conditions and mechanical damage.
Disposal We recommend to dispose of the measuring cell as electronic waste.
Contamination Cleaning procedure
Lime sediments Immerse in acetic acid for 5 minutes (volume share =
10 %)
Fat/oil Clean with warm water that contains washing-up liquid

What to do if ... VisoTurb®900-P
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4 What to do if ...
5 Technical data
5.1 General data
Error symptom Cause Remedy
No turbidity display – No connection between meter and
turbidity sensor
– Cable defective
– Establish connection between
meter and turbidity sensor
Implausible turbidity val-
ues
– There are gas bubbles (e.g. air
bubbles) in front of the
measurement window
– Remove the gas bubbles, e.g.
by immersing the sensor at an
angle
– Incorrect calibration,e.g.:
– Unsuitable calibration standard
solutions (e.g. too old)
– Unsuitable calibration environ-
ment (e.g. due to gas bubbles,
reflection, light)
– Check the calibration
Error message,
OFL
– Measured value outside the
measuring range
– Select a suitable measuring
medium
Measured values too low – Measurement window soiled – Clean the measurement window
Measured values too
high
– Reflection at the walls or bottom of
the measuring vessel
– Keep the minimum distance of the
sensor towards the walls and bot-
tom of the measuring vessel (see
section 2.4)
– Incidence of light – Use a light-proof measuring ves-
sel
General features Measuring principle Nephelometric
according to ISO 7027 / DIN EN 27027
Wavelength: 860 nm ± 15 nm
Light source Infrared LED
Dimensions
(in mm)
121.3
222.8
15.8 21.7

VisoTurb®900-P Technical data
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Weight Approx. 83 g (without cable)
Materials Shaft Titanium
Connection head POM
IDS plug Connection type 4-pin, watertight plug connection with locking
device, reverse polarity protected
Materials – Plastic parts: Fiber-glass reinforced Noryl,
TPU, TPC-ET, POM, PEEK, PBT
– O-ring: FPM
– Contacts gold-plated
Pressure
resistance
Sensor with connection
cable
IP 68 (10 x 105Pa or 10 bar)
Cable plug IP 67 (when plugged in)
The VisoTurb®900-P meets the requirements according to article 3(3) of
the directive, 97/23/EC ("pressure equipment directive").
Measurement
conditions
Turbidity measuring range 0.0 ... 4000.0 FNU/NTU
Temperature range -5 ... 50 °C (23 ... 158 °F)
Max. admissible overpres-
sure
10 x 105Pa (10 bar)
Minimum depth of immer-
sion
2 cm
Storage
conditions
Recommended storing
method
In air
Storage temperature -20 ... 80 °C
Characteristics
when delivered
Responding behavior t63 (63 % of the final value display after)
<2s

Wear parts and accessories VisoTurb®900-P
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5.2 Measuring ranges, resolution, accuracy
5.3 Accuracy of the IDS measuring technique
6 Wear parts and accessories
Measuring ranges,
resolution
Measured parameter Measuring range Resolution (max.)
FNU/NTU 0.0 ... 4000.0 0.1
Measured parameter Measuring range Accuracy (± 1 digit)
FNU/NTU 0.0 ... 999.9 0.3 FNU or ± 2 % of the measured value (de-
pending on the greater value)
1000.0 ... 4000.0 ± 5 % of measured value
Accessories for
VisoTurb®900-P
Description Model Order no.
IDS connecting cable, 1.5 m AS/IDS-1.5 903 850
IDS connecting cable, 3 m AS/IDS-3 903 851
IDS connecting cable, 6 m AS/IDS-6 903 852
IDS connecting cable, 10 m AS/IDS-10 903 853
IDS connecting cable, 15 m AS/IDS-15 903 854
IDS connecting cable, 20 m AS/IDS-20 903 855
IDS connecting cable, 25 m AS/IDS-25 903 856
IDS connecting cable, 40 m AS/IDS-40 903 857
IDS connecting cable, 60 m AS/IDS-60 903 858
IDS connecting cable, 100 m AS/IDS-100 903 859
Kit for turbidity calibration
Turbidity standards
124.0 FNU/NTU and 1010.0 FNU/NTU)
Cal-Kit VT900 600 702
Calibration and measurement bottle, 0.5 l SB VT 900 600 704
Protective armouring (/K variant)
(The /S variant has an impact on the measu-
red value.)
A 925-P/K 903 839
Further accessories are listed in the price list of the WTW catalog
"Lab and Field Instrumentation".