Endress+Hauser Turbimax CUS51D Manual

TI00461C/07/EN/14.12
71159923
Technical Information
Turbimax CUS51D
Sensor for turbidity and solids content
Installation and immersion sensor for low, middle and high turbidity and
solids concentrations
Application
Turbimax CUS51D is a sensor for all applications of wastewater
treatment.
• Turbidity measurement in the outlet
• Suspended solids in the activated sludge basin and in the
recirculation
• Suspended solids in the sludge treatment
• Filterable solids in the outlet
Your benefits
• All sensor principles (90°, 135° and four-beam pulsed light)
are included in the sensor head and allow optimal adaption to
the measurement task.
• The sensor is factory-calibrated (basis formazine). All
selectable applications (e.g. activated sludge) are precalibrated
and allow quick and easy commissioning.
• Standardized communication (Memosens technology) allows
"plug and play".
• Intelligent sensor - all characteristics and calibration values
are stored in the sensor.
• Calibrations provided by the customer with up to 5 points -
realizable in lab or on site.

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Function and system design
Measuring principle For turbidity measurement a light beam is sent through the medium and is diverted from its original direction
by optically denser particles, e.g. solid matter particles. This process is also called scattering.
The impinging light will be scattered in different angles. Two angles are of interest in this matter:
• The scattered light in the 90° direction is less influenced by the size of the particles.
• The scattered light in the 135° direction gives enough information also at a high number of particles.
a0012986
Principle operating mode of the turbidity sensor
1 Light source
2 135° light receiver
3 90° light receiver
If only a small number of particles is in the medium, most of the light will be scattered to the 90° channel and
less light will be scattered to the 135° channel. When the number of particles increases the relationship will
change (more light scattered to the 135° channel, less light scattered to the 90°channel).
a0013158
Signal distribution depending on the number of particles
Ir Relative intensity
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Deflection of the light
1
2
3
4
Light source
Light beam
particle
Scattered light
1
2
3
4
4
4
90°
135°
123
1
Ir
FNU
90°
135°

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Sensor design The turbidity sensor CUS51D is equipped with two independing sensor units that are arranged in parallel. The
application-specific analysis of both signals results in stable measured values.
a0012966
Arrangement of the light souces and the light receivers
1,2 Light sources 1 and 2
3,5 135° light receivers
4,6 90° light receivers
This allows the optimal turbidity and suspended solids measurement:
• For low turbidity values preferably the 90° channel is used.
• For average and high turbidity values and for suspended solids measurement the 135° channel is used.
• The dual sensor technology allows operation with a large range of soiling compensation, e.g. suspended
solids measurement in the activated sludge basin (basis: four-beam pulsed light).
Based on the chosen application the appropriate model is used automatically inside the sensor.
Note!
The available sensor types differ in their measuring ranges and therefore in the selection of the available
applications.
Measurement methods Four-beam pulsed light method
The method is based on two light sources and four light receivers. Long-life LEDs are used as monochromatic
light sources. To eliminate interference from extraneous light sources, these LEDs are pulsed.
Two measuring signals are detected at the four light receivers. The eight measuring signals are processed in the
sensor and are converted into turbidity units and solids concentrations.
The four-beam pulsed light method compensates the sensor soiling as well as the wearing of the optical
components.
The number of the used signals depends on the application.
a0012987
Four-beam pulsed light method
S1S2Light sources
E90 90° channel light-receiver
E135 135° channel light-receiver
12
3
4
5
6
S1E1-135
E2-135
S2
E1-90
E2-90

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90° scattered light method
The measurement uses a wavelength of 860 nm like described in ISO 7027 / EN 27027.
The transmitted light beam is scattered by the solid matter particles in the medium. The scattered beams are
detected by scattered light receivers which are arranged at an angle of 90 ° to the light sources. The turbidity
of the medium is determined by the amount of the scattered light.
135° backscattered light method
The transmitted light beam is scattered by the solid matter particles in the medium. The backscattered beams
are detected by scattered light receivers, which are arranged next to the light sources. The turbidity of the
medium is determined by the amount of backscattered light.
This method is used to measure high turbidity values.
Sensor monitoring The optical signals are continuously monitored und checked for plausibility
Discrepancies are reported via error messages by the transmitter.
The sensor check system of the Liquiline M reports the following failure conditions:
• Implausible high or low measuring values
• Disturbed controlling due to erroneous measuring values
a0013168
Principle of the 90° scattered light method
S = Light source
E = Light receiver
P = Particle
a0013304
Principle of backscattered light method
I0= Intensity of transmitted light
IS= Intensity of backscattered light
A = Geometric factor
C = Concentration
P = Particle
f(α) = Angle dependence
S
E
a
P
S1
E1P
I0
IS
a
I =I ·C·A·f( )
s0 a

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Applications
* compensation of contamination with four-beam pulsed light
Measuring system A complete measuring system comprises:
• Turbidity sensor Turbimax CUS51D
• Transmitter Liquiline
• Assembly:
– Assembly Flexdip CYA112 and holder system Flexdip CYH112 or
– Retractable assembly , e.g. Cleanfit CUA451
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Measuring system with immersion assembly (example)
Model name Application Unit Compensation*
Formazine Process water, sewage treatment plant outlet FTU / FNU
Kaolin Filterable solids, process water, sewage treatment plant
outlet, activated sludge in low concentration
mg/l ; g/l;
ppm; %
SiO2SiO2, mineralic solids (sands) g/l; ppm; % X
TiO2TiO2, (white medium) g/l; ppm; % X
Activated sludge Activated sludge basin and comparable medium g/l; ppm; % X
Excess sludge Excess sludge, primary sludge, thickened sludge g/l; ppm; % X
Digested sludge Digested sludge, black - homogeneous g/l; ppm; %
1
2
3
1
4
5
1 Holder system Flexdip CYH112 4 Assembly Flexdip CYA112
2 Transmitter Liquiline 5 Turbidity sensor Turbimax CUS51D
3 Weather protection roof

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a0013334
Measuring system with immersion assembly (example)
2
3
5
4
1
1 Transmitter Liquiline 4 Assembly Flexdip CYA112
2 Weather protection roof 5 Turbidity sensor Turbimax CUS51D
3 Holder system Flexdip CYH112
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Measuring system with retractable assembly (example)
1 Turbidity sensor Turbimax CUS51D
2 Transmitter Liquiline
3 Retractable assembly Cleanfit CUA451
4 Flow direction
1
3
4
2

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a0013386
Measuring system with immersion assembly and chain holder system
1
2
3
1
4
5
4
1 Holder system Flexdip CYH112 4 Assembly Flexdip CYA112
2 Transmitter Liquiline CM44x 5 Turbidity sensor Turbimax CUS51D
3 Weather protection roof

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Input
Measuring variables Turbidity
Solids content
Temperature
Measuring range
Note!
Measuring range of solids content:
For solids the achievable measuring ranges are depending of the actual medium and can deviate from the
recommended operating ranges. Nonhomogeneous media produce fluctuations in measured values and restrict
the measuring range.
Power supply
The sensor will be connected to the transmitter as follows:
• With the M12 plug (version CUS51D-xxxxBxxx) or
• the fixed cable has to be connected to the terminal as follows (version CUS51D-xxxxAxxx):
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Sensor connection
The maximum cable length is 100 m (328 ft).
CUS51D-**C1 Application
Turbidity 0 to 4000 FNU
display range up to 9999 FNU
Formazine
Solids content 0 to 4 g/l Kaolin, filterable solids
Temperature -20 to +80 °C (-4 to +176 °F)
CUS51D-**D1
Turbidity 0 to 4000 FNU
display range up to 9999 FNU
Formazine
Solids content 0 to 300 g/l Solids content according to chosen
0 to 30 % application (see list)
Temperature -20 to +80 °C (-4 to +176 °F)

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Performance characteristics
Maximum measured error
Wavelength 860 ± 30 nm
Factory calibration FNU, FTU and solids concentration according to the application table
Standard: 3 points
Applications The sensor is factory calibrated in the application "formazine" and hereof derived for "kaolin filterable solids)".
Further precalibrated applications are optimized for the corresponding medium.
The calibration can be performed up to 5 points.
Note!
For solids the achievable measuring ranges are depending of the actual medium and can deviate from the
recommended operating ranges. In this case a 3-point-calibration is recommended.
Drift Thanks to electronic control the sensor works drift compensated in a wide range.
Limit of detection
Turbidity < 2% of the measured value or 0.1 FNU (the respectively larger value is valid)
Solids < 5 % of the measured value or 1 % of full scale ( the respectively larger value is valid); valid
for sensors in the calibrated measuring range
Application Recommended working ranges CUS51D-
C1 D1
Factory calibration formazine 0 to 4000 FNU X X
Factory calibration kaolin 0 to 4 g/l X X
Application SiO25 to 100 g/l X
Application titanium dioxide 0.2 to 150 g/l X
Application activated sludge 0.5 to 15 g/l X
Model return sludge 3 to 50 g/l X
Application digested sludge / ooze 5 to 100 g/l / 300 g/l X
Application Measuring range Limit of detection
Formazine
0 to 50 FNU 0.006 FNU
0 to 9999 FNU 0.4 FNU
Kaolin 0 to 4000 mg/l 0.85 mg/l

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Installation conditions
Installation instructions Mounting applications:
• with retractable assembly Cleanfit W CUA451
• with wastewater assembly Flexdip CYA112 and holder system Flexdip CYH112
• with flow assembly Flowfit CYA251
a0013009
Installation with retractable assembly
Arrow 1 shows the flow direction.
The installation angle αmust not exceed 90°.
The recommended installation angle is 75°.
The optical windows of the sensor have to be aligned parallel to
the flow direction (α= 90°) or face the flow direction
(α< 90°).
For manual insertion/retraction of the assembly the medium
pressure may not exceed 2 bar (29 psi).
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Installation with wastewater assembly
The arrow shows the flow direction.
The installation angle is 45° (recommended) or 90°.
If you use the sensor in open basins, install the sensor in a way
no bubbles can build up around the optical windows.
If you use the sensor in strong aerated basins install the sensor
in an installation angle of 90° to minimize the influence of
bubbles.
a0015169
Installation with flow assembly CYA251
The installation angle is 90°.
a
1