Nivus NivuFlow Stick User manual

FLOW portable
Instruction Manual
Mobile Flow Measurement System NivuFlow Stick
for Flow Measurement in Flowing Waters
Firmware version: 3.3.X
Document revision 00 / 27.01.2020
Original manual: German / rev. 01 as of 15.01.2020

Instruction Manual
NivuFlow Stick
Page 2 NivuFlow Stick - rev. 00 / 27.01.2020
NIVUS AG
Burgstrasse 28
8750 Glarus, Switzerland
Phone [phone]
Fax [phone]
[e-mail]
www.nivus.de
NIVUS Austria
Mühlbergstraße 33B
3382 Loosdorf, Austria
Phone [phone]
Fax [phone]
[email protected]
www.nivus.de
NIVUS Sp. z o.o.
ul. Hutnicza 3 / B-18
81-212 Gdynia, Poland
Phone [phone]
Fax [phone]
[email protected]
www.nivus.pl
NIVUS France
67870 Bischoffsheim, France
Phone [phone]
[email protected]
www.nivus.fr
NIVUS Ltd., United Kingdom
Wedgewood Rugby Road
Weston under Wetherley
Royal Leamington Spa
CV33 9BW, Warwickshire
Phone [phone]
[email protected]
www.nivus.com
NIVUS Middle East (FZE)
Building Q 1-1 ap. 055
P.O. Box: 9217
Sharjah Airport International
Free Zone
Phone [phone]
Fax [phone]
middle-[email protected]
www.nivus.com
NIVUS Korea Co. Ltd.
#2502 M Dong, Technopark IT Center,
32 Song-do-gwa-hak-ro, Yeon-su-gu,
INCHEON, Korea 21984
Phone [phone]
Fax [phone]
[email protected]
www.nivus.com
NIVUS Vietnam
21 Pho Duc Chinh, Ba Dinh
Hanoi, Vietnam
Phone [phone]
[email protected]
www.nivus.com

Copyrights and property rights
NivuFlow Stick - rev. 00 / 27.01.2020 Page 3
Copyrights and property rights
This document and its contents are proprietary to NIVUS GmbH and are not to be repro-
duced or copied without the express written permission of NIVUS GmbH.
Violations oblige to compensation.
Important Note
This manual may exclusively - even in parts - be copied or translated in any other way with
the express written consent of NIVUS GmbH.
Translation
If the device is sold to a country in the European Economic Area (EEA) this instruction manu-
al must be translated into the language of the country in which the device is to be used.
Should the translated text be unclear, the original instruction manual (German) must be con-
sulted or the manufacturer contacted for clarification.
Copyright
No part of this publication may be reproduced, transmitted, sold or disclosed without prior
permission. Damages will be claimed for violations. All rights reserved.
Names
The use of general descriptive names, trade names, trademarks and the like in this manual
does not entitle the reader to assume they may be used freely by everyone. They are often
protected registered trademarks even if not marked as such.

Instruction Manual
NivuFlow Stick
Page 4 NivuFlow Stick - rev. 00 / 27.01.2020
Document modifications
Rev.
Modifications
Editor in
charge
Date
00
First version based on the German document
MoG
27.01.2020

Table of contents
NivuFlow Stick - rev. 00 / 27.01.2020 Page 5
Table of contents
Copyrights and property rights 3
Document modifications 4
Table of contents 5
General 9
1About this manual......................................................................................9
1.1 Applicable documentation .....................................................................9
1.2 Signs and definitions used ..................................................................10
2Connections and Operating Elements ....................................................10
2.1 Power Supply ......................................................................................10
2.1.1 Flow measurement system ..............................................................10
2.1.2 Rechargeable Batteries ...................................................................10
2.2 NivuFlow Stick Operating Elements....................................................10
Safety Instructions 11
3Used Symbols and Signal Words............................................................11
3.1 Valuation of the accident level ............................................................11
3.2 Warning notices on the product (option) .............................................12
4Safeguards and Precautions...................................................................12
5Warranty..................................................................................................12
6Liability Disclaimer...................................................................................13
7Use in accordance with the requirements...............................................13
8User’s Responsibilities ............................................................................14
9Personnel requirements ..........................................................................14
Delivery, Storage and Transport 15
10 Delivery ...................................................................................................15
11 Reception inspection ...............................................................................15
12 Storage....................................................................................................15
13 Transport .................................................................................................15
14 Return......................................................................................................15
Product specification 16
15 Product Construction and Dimensions....................................................16
15.1 Connectable sensors ..........................................................................17
16 Device identification ................................................................................17
17 Specifications ..........................................................................................18
18 Configuration / Device Types ..................................................................18
Functional description 19
19 Operating Ranges ...................................................................................19
20 Functional Principles ...............................................................................19
20.1 Flow velocity measurement Cross correlation ....................................19
20.2 Level measurement Pressure .............................................................21

Instruction Manual
NivuFlow Stick
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Using the NivuFlow Stick Measurement System 22
21 General Information on Device Use ........................................................22
21.1 Energy-saving mode (Powerdown) .....................................................22
21.2 Gaskets ...............................................................................................22
21.3 Degree of protection............................................................................22
22 Executing Flow Measurements ...............................................................22
22.1 Required measuring equipment and aids ...........................................22
22.2 Prerequisites to execute Flow Measurements ....................................23
22.3 Steps to execute Flow Measurements................................................23
Operation start-up 25
23 Notes to users .........................................................................................25
24 First steps................................................................................................25
25 Indication System of Status LED on NivuFlow Stick...............................25
26 Setting Up Connection ............................................................................26
26.1 General................................................................................................26
26.2 Android Operating System ..................................................................26
26.3 iOS Operating System ........................................................................29
26.4 Windows Operating System................................................................32
27 Menu Operation/Overview ......................................................................34
27.1 Display Overview ................................................................................34
27.2 Saving Parameters..............................................................................35
27.3 Menus..................................................................................................36
Parameter Setting 37
28 General Programming.............................................................................37
28.1 Save Parameters ................................................................................37
28.2 Change WLAN Password ...................................................................37
28.3 Change Instrument SSID ....................................................................38
28.4 Lost Password.....................................................................................38
29 Parameter Functions ...............................................................................39
29.1 Main Menu ..........................................................................................39
29.2 Functions of the first Menu Level ........................................................39
29.2.1 Menu - Application ...........................................................................39
29.2.2 Menu - Readings..............................................................................40
29.2.3 Menu - System .................................................................................40
29.2.4 Menu - WLAN...................................................................................41
29.2.5 Menu - Battery (12V)........................................................................42
30 Application Parameters Menu .................................................................42
30.1 Menu Measure Place ..........................................................................42
30.1.1 Name of measurement place...........................................................43
30.1.2 Reference Number...........................................................................43
30.1.3 Wall Material ....................................................................................43
30.1.4 Width ................................................................................................44
30.1.5 Offset................................................................................................44
30.1.6 Calculation .......................................................................................45
30.1.7 Bank left, k(Bank left), Bank right and k(Bank right) ........................45
30.1.8 Measurement Points ........................................................................46
30.1.9 Quality Trigger min...........................................................................46
30.1.10 Measurement Duration ....................................................................46
30.1.11 Damping...........................................................................................46

Table of contents
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30.1.12 Stability.............................................................................................47
30.2 Diagnostics Menu................................................................................47
31 Readings Menu .......................................................................................47
31.1 Menu >Readings<: Information and Parameter Setting Options........47
31.1.1 Use of the >Readings< Menu ..........................................................47
31.1.2 Name of Measurement Place ..........................................................48
31.1.3 Reference Number...........................................................................48
31.1.4 Notes ................................................................................................48
31.1.5 Quality Trigger min., Calculation, Bank and Measurement
Points ...............................................................................................48
31.1.6 Flow, Level, Velocity, Area, Wetted Perimeter and Hydraulic
Radius ..............................................................................................48
31.1.7 Table: Position, Level, Flow and Factor...........................................49
31.1.8 Save .................................................................................................49
31.1.9 Load .................................................................................................49
31.1.10 Download .........................................................................................49
31.1.11 Erase ................................................................................................50
32 Data Memory Menu.................................................................................50
32.1 In General ...........................................................................................50
32.1.1 from / to ............................................................................................50
32.1.2 File Format .......................................................................................51
32.1.3 Data Depth .......................................................................................51
32.1.4 Download .........................................................................................51
32.1.5 Delete Storage .................................................................................51
33 System Parameter Menu ........................................................................51
33.1 Menu Information ................................................................................51
33.2 Menu Region Settings.........................................................................52
33.2.1 (Operation) Language ......................................................................52
33.2.2 Date Format .....................................................................................52
33.2.3 Units .................................................................................................52
33.2.4 Units Memory ...................................................................................53
33.3 Menu Time/Date..................................................................................54
33.4 Menu Error Messages.........................................................................56
33.5 Menu Service ......................................................................................56
33.5.1 Service Level....................................................................................57
33.5.2 Reboot..............................................................................................57
33.5.3 Parameter Reset ..............................................................................57
34 WLAN Parameter Menu ..........................................................................57
35 Battery (12V) Parameter Menu ...............................................................58
Main Display 59
35.1 Information on the Main Screen..........................................................59
35.2 Select/Open the Pop-Up Menus .........................................................59
35.3 “Flow” Menu Main Screen ...................................................................60
35.4 “Level” Menu Main Screen ..................................................................60
35.5 “Velocity” Menu Main Screen..............................................................61
35.6 “Position 1/x” Menu Main Screen........................................................61
Diagnostics 64
36 Diagnostics Menu Principles ...................................................................64
37 Diagnostics h-Sensors Menu ..................................................................64
38 Diagnostics v-Sensors Menu ..................................................................65

Instruction Manual
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39 Diagnostics Signal Analysis Menu ..........................................................66
Maintenance and Cleaning 69
40 Maintenance............................................................................................69
40.1 Maintenance Interval...........................................................................69
40.2 Customer Service Information ............................................................69
41 Cleaning ..................................................................................................69
41.1 Transmitter ..........................................................................................69
41.2 Sensors ...............................................................................................69
42 Dismantling/Disposal...............................................................................70
43 Installation of spare parts and parts subject to wear and tear ................70
44 Accessories .............................................................................................70
Index 71
Credits and Licenses 73
45 List of references of the licenses an codes used ....................................73
Approvals and Certificates 74

General
NivuFlow Stick - rev. 00 / 27.01.2020 Page 9
General
1 About this manual
Important note
READ CAREFULLY BEFORE USE.
KEEP IN A SAFE PLACE FOR LATER REFERENCE.
The manual belongs to the mobile flow measurement system NivuFlow Stick and is for the in-
tended use of the device. This manual is oriented exclusively to qualified expert personnel.
Read this instruction manual carefully and completely prior to use since it contains relevant
information on this product. Observe the notes and particularly follow the warning notes and
safety instructions.
Keep this manual in a safe place and make sure it is available for the users of this product at
any time.
If you should have problems to understand information contained within this instruction man-
ual contact one of the legally associated companies and subsidiaries of NIVUS group for fur-
ther support. The companies and subsidiaries of NIVUS group cannot be held responsible for
damage to persons or materials due to incorrectly understood information in this instruction
manual.
In the case of selling the instrument this instruction manual shall be provided to the purchaser
since it is a part of the standard delivery.
1.1 Applicable documentation
For the installation and operation of the complete system extra instruction manuals or tech-
nical descriptions may be required apart from this manual.
•Standard specifications DIN ISO 748 “Hydrometry – Measurement of liquid flow in open
channels using currentmeters or floats (ISO 748:2007); German version
EN ISO 748:2007” (this manual is based on the knowledge of the standard contents)
•VDI/VDE Guideline 2640: “Measurement of fluid flow in closed conduits; General guide-
lines and mathematical basics” (available in German)
•Technical Instructions for Correlation Sensors and external Electronic Box
These manuals are provided with the auxiliary units or sensors and/or are available as down-
load on the NIVUS homepage.

Instruction Manual
NivuFlow Stick
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1.2 Signs and definitions used
Image
Meaning
Remark
(Action) Step Action to be performed by you.
Note the numbering of action steps. Observe the
order of the steps.
 Cross-reference Refers to further or detailed information.
>Text< Parameter or Menu Indicates a parameter or a menu that is selected
or described.
Reference to document Refers to an accompanying documentation.
Table 1 Structural elements within the manual
2 Connections and Operating Elements
2.1 Power Supply
2.1.1 Flow measurement system
NivuFlow Stick is powered either with Type AA rechargeable batteries or Type AA standard
batteries (eight pcs.) (see Sect. “17 Specifications”).
1 Battery compartment (for four rechargeable/standard batteries)
2 Measurement transmitter
Fig. 2-1 Power supply by battery packs
2.1.2 Rechargeable Batteries
Rechargeable batteries shall be charged externally by using a standard battery charger.
2.2 NivuFlow Stick Operating Elements
NivuFlow Stick is equipped only with an On/Off switch and a Reed contact (status LED) with
no other control elements. Instrument operation and the setting of parameters are carried out
completely by using smartphone, tablet, notebook and PC.
Also refer to the instruction manuals of your preferred smartphone, tablet,
notebook or PC.

Safety Instructions
NivuFlow Stick - rev. 00 / 27.01.2020 Page 11
Safety Instructions
3 Used Symbols and Signal Words
3.1 Valuation of the accident level
The general warning symbol indicates the risk of personal injuries or death. In the text sec-
tion the general warning symbol is used in conjunction with the signal words described
below.
DANGER Warnings in high degree of risk
Indicates a high-risk, imminently hazardous situation which will result in death or serious
injury if not avoided.
WARNING Warnings in medium degree of risk
Indicates a possible danger with medium risk which may result in a life-threatening situa-
tion or (severe) bodily injury if it is not avoided.
CAUTION Warnings in low-risk or property damages
Indicates a possible danger with moderate risk which may result in minor or moderate per-
sonal injury or material damage if not avoided.
WARNING Danger by electric voltage
Indicates a hazard with a high risk of electric shock which may result in a life-threatening
situation or (severe) bodily injury if it is not avoided.
Important Note
Contains information that should be highlighted.
Indicates a potentially damaging situation which can result in damage to the product or to
an object in its environment.
Note
Contains information and facts.

Instruction Manual
NivuFlow Stick
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3.2 Warning notices on the product (option)
General warning label
This symbol is for operators to refer to this manual.
Observing the information contained therein is required in order to maintain protection
measures provided by the instrument during installation procedures and operation.
4 Safeguards and Precautions
Working with NIVUS instruments requires to observe and to follow the safety
measures and precautions below generally and at any time. These notes and warnings
will not be repeated for each description within the document.
WARNING
Check danger through explosive gases
Prior to beginning works make sure to observe any regulations on safety at work as well as
(especially in closed canal systems) to check the potential risk due to explosive gases. Use
a gas warner to check.
Disregarding may lead to personal injury or damage your equipment.
WARNING Germ contamination
Parts can be contaminated with dangerous germs, especially if the sensors are used in
waste water applications. Therefore, appropriate precautions must be taken when contact-
ing cables and sensors.
Wear protective clothing.
WARNING Observe occupational safety regulations
Before starting and while executing works, observing the work safety regulations needs to
be checked constantly.
Disregarding these regulations may lead to personal injury.
Integrated buffer battery
The integrated buffer battery may only be exchanged by NIVUS staff or personnel author-
ised by NIVUS. Infringements lead to a limitation of the warranty (see Sect. “5 Warranty”).
5 Warranty
The device has been functionally tested before delivery. If it is used as intended (see Sect. “7
Use in accordance with the requirements”) and the operating instructions, and the safety
notes and instructions contained therein, are observed, no functional restrictions are to be
expected and perfect operation should be possible.
Please also note in this regard the next Sect. “6 Liability Disclaimer”.
Limitation of warranty
In the event of non-compliance with the safety instructions and instructions in this docu-
ment, the companies of the NIVUS group of companies reserve the right to limit the warran-
ty.

Safety Instructions
NivuFlow Stick - rev. 00 / 27.01.2020 Page 13
6 Liability Disclaimer
The legally associated companies and subsidiaries of NIVUS group assume no liability
•for damages owing to a change to this document. The legally associated companies
and subsidiaries of the NIVUS group reserve the right to change the contents of this
document and this disclaimer at any time and without any notice.
•for damages to persons or objects resulting from failure to comply with applicable
regulations. When connecting, commissioning and operating the sensors, all available
information and higher local legal regulations (in Germany e.g. VDE regulations) such
as applicable Ex regulations as well as safety requirements and regulations in order to
avoid accidents shall be adhered to.
•for damages to persons or objects resulting from improper use. For safety and warran-
ty reasons, all internal work on the instruments beyond that involved in normal installa-
tion and connection, must be carried out only by qualified NIVUS personnel or persons
or companies authorised by NIVUS.
•for damages to persons or objects resulting from the use of instruments in technically
imperfect condition.
•for damages to persons or objects resulting from the use of instruments not in accord-
ance with the requirements.
•for damages to persons or objects resulting from failure to comply with safety infor-
mation contained within this instruction manual.
•for missing or incorrect measurement values or resulting consequential damages due to
improper installation.
7 Use in accordance with the requirements
Note
The instrument is intended solely for the purpose described below.
Modifying or using the instruments for any other purposes without the written consent of the
legally associated companies and/or subsidiaries of NIVUS group will not be considered as
use in accordance with the requirements.
The legally associated companies and subsidiaries of NIVUS group cannot be held respon-
sible for any damage resulting from improper use. The user alone bears any risk.
The flow measurement system NivuFlow Stick and associated sensor system is designed for
the mobile flow measurement covering the scope of discharge measurement in flowing wa-
ters.
The NivuFlow Stick is designed and manufactured in accordance with the current state of the
art and with the recognised safety rules and regulations applicable at the time this document
is issued. Danger to persons or material damage cannot be completely ruled out, however.
The maximum permissible limit values as specified in Sect. “17 Specifications” shall be nec-
essarily observed. Any case varying from these conditions which is not approved by NIVUS
GmbH in written form is left at the owner’s risk.

Instruction Manual
NivuFlow Stick
Page 14 NivuFlow Stick - rev. 00 / 27.01.2020
8 User’s Responsibilities
Observe and comply with all guidelines and requirements
In the EEA (European Economic Area) national implementation of the framework directive
89/391/EEC and corresponding individual directives, in particular the directive 2009/104/
EC concerning the minimum safety and health requirements for the use of work equipment
by workers at work, as amended, are to be observed and adhered to. In Germany e.g. the
Industrial Safety Ordinance must be observed.
Make sure to have a local operating permit available and observe the associated conditions.
In addition to this you must observe environmental requirements and local laws on the follow-
ing points:
•Personnel safety (accident prevention regulations)
•Safety of work materials and tools (safety equipment and maintenance)
•Disposal of products (laws on wastes)
•Disposal of materials (laws on wastes)
•Cleaning (cleansing agents and disposal)
9 Personnel requirements
The flow measurement system shall be used only by personnel meeting the demands as fol-
lows:
•Expert personnel with relevant training and appropriate qualification
•Personnel authorised by the plant operator
Qualified personnel
within the context of this documentation or the safety notes on the product itself are per-
sons who are sufficiently familiar with installation, mounting, starting up and operation of
the product and who have the relevant qualifications for their work; for example:
I. Training, instruction or authorisation to activate/deactivate, isolate, ground and
mark electric circuits and devices/systems according to the safety engineering
standards.
II. Education and instruction according to the standards of safety engineering regard-
ing the maintenance and use of adequate safety equipment.
III. First aid training

Delivery, Storage and Transport
NivuFlow Stick - rev. 00 / 27.01.2020 Page 15
Delivery, Storage and Transport
10 Delivery
The standard delivery of the NivuFlow Stick basically contains:
•Flow measurement system type NivuFlow Stick (according to shipping documents)
•Instruction manual (incl. certificates of conformity) containing any relevant information
on how to operate the NivuFlow Stick
Check extra accessories depending on your order and by using the delivery note.
11 Reception inspection
Check the packaging for visible damage immediately after receipt. Any possible damage in
transit shall be instantly reported to the carrier. Furthermore a written report shall be sent to
NIVUS GmbH in Eppingen.
Incomplete deliveries shall be reported in writing either to your local representative or directly
to the NIVUS GmbH in Eppingen within two weeks.
Important note
Objections cannot be rectified later.
12 Storage
The permissible maximum values regarding ambient conditions such as temperature and
humidity according to Sect. “17 Specifications” shall be necessarily observed.
Protect the instrument from corrosive or organic solvent vapours, radioactive radiation as well
as strong electromagnetic radiation.
Use the original packaging for storage.
13 Transport
Protect NivuFlow Stick against heavy impacts, shocks, punches or vibration using appropri-
ate safety measures such as belts or similar.
14 Return
In case of a required reshipment return the unit at customer cost to NIVUS GmbH in Ep-
pingen using the original packaging.
Insufficiently franked shipments will not be accepted!

Instruction Manual
NivuFlow Stick
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Product specification
15 Product Construction and Dimensions
1 Level ruler on guide bar
2 Smartphone holder
3 CSM flow velocity wedge sensor with pressure measurement
4 Measurement transmitter
5 Handle
6 Fastening clip for transmitter
7 Pressure compensation element for the sensor
8 Battery compartment (for four batteries each)
9 Status LED
10 On/Off switch
11 Locking pin to remove the sensor from the tube
12 Spirit level for alignment
Fig. 15-1 Device setup NivuFlow Stick

Product specification
NivuFlow Stick - rev. 00 / 27.01.2020 Page 17
15.1 Connectable sensors
1 CSM flow velocity wedge sensor with pressure measurement
Fig. 15-2 Connectable sensors
16 Device identification
The instructions contained within this manual are valid only for the type of device specified on
the title page. The nameplate is fixed on the side of the enclosure and contains the following:
•Name and address of NIVUS GmbH
•CE label
•Information on type and series incl. article and serial number
•Year of manufacture: the first four digits of the serial number represent the year and the
week number of manufacture (2002…..)
In case of enquiries and ordering replacement parts it is important to specify article number
as well as the serial number of the respective transmitter or sensor. This ensures correct and
quick processing.
Fig. 16-1 Nameplate NivuFlow Stick
Check nameplates
Check the delivered instrument for accordance with your order by identifying the name-
plate.
The declaration of conformity is located at the end of the manual.

Instruction Manual
NivuFlow Stick
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17 Specifications
Measurement principle - Ultrasonic cross correlation with real flow profile measure-
ment (flow velocity)
- Hydrostatic (depth measurement relative to atmospheric
pressure)
Power supply - 8x rechargeable batteries, customary, nominal voltage 1.2 V
or
- 8x standard batteries Type AA, customary, nominal voltage
1.5 V
Battery life 12 hrs. with continuous operation (if powered with 2,650 mAh
batteries)
Enclosure Degree of protection: IP67 (closed)
Weight approx. 4.1 kg
Operating temperature -20…+70 °C
Storage temperature -30…+70 °C
Handling On/Off switch; via WLAN with customer display and operating
module (smartphone, tablet, notebook etc.)
Flow velocity measurement Measurement range: -1…+6 m/s
Resolution: 0.001 m/s
Accuracy: 1 %
Depth measurement Resolution: 1 mm
Accuracy: < 0.5 % of final value
Temperature measurement Resolution: 0,1 °C
Accuracy: 0.1 °C
Acoustic frequency 1…3 MHz
Depth of medium Minimum 30 mm (above the sensor)
Data storage 1,400 discharge measurements
Data transfer/communication via WLAN
Sensor CSM flow velocity wedge sensor with pressure measurement
Table 2 Specifications
Sensor
Construction and description of the respective sensor as well as its specifications can be
found in the “Technical Instructions for Correlation Sensors and external Electronic Box”.
The technical description is available as download from www.nivus.com.
18 Configuration / Device Types
The cross correlation version of the mobile flow measurement system is manufactured with a
CSM flow velocity wedge sensor with pressure measurement.
NFS002
NivuFlow Stick; mobile measurement system for discharge measurement in flow-
ing waters
Accessories see Sect. “44 Accessories”.

Functional description
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Functional description
19 Operating Ranges
NivuFlow Stick is a mobile flow measurement system. The instrument is designed mainly for
measurement in slight to heavily polluted aqueous liquids of various compositions.
It is used within the scope of discharge measurements in rivers, flumes and channels featur-
ing various shapes and dimensions.
An overview on connectable sensors can be found in Sect. “15.1 Connectable sensors”.
Note on the ultrasonic reflection principle
The measurement method for flow velocity detection is based on the ultrasound reflection
principle.
Hence, it is indispensable for the system to work that there are particles in the water, which
are able to reflect the ultrasonic signal sent by the sensor (dirt particles, gas bubbles or
similar).
20 Functional Principles
20.1 Flow velocity measurement Cross correlation
The piezo crystal has a slope to the flow direction and operates as a flow velocity sensor.
Here an ultrasonic burst with a defined angle is sent into the medium. All the particles in the
measurement path (air, dirt) reflect a small amount of the ultrasonic signal. The result is a
particular signal depending on shape and size of the particles.
Hence, the multitude of the reflected signals results in a reflection pattern (see Fig. 20-1). The
piezo crystal receives this pattern again, which then is converted into electric signals and will
be saved in a built-in digital signal processor (DSP).
Fig. 20-1 Situation at first signal detection
After a certain period a second ultrasonic burst is sent into the medium. The newly generated
reflection signal is saved in the DSP too.
In various flow levels there are different flow velocities (flow velocity profile).
Depending on the level, the reflecting particles’ movement away from the first measurement
point therefore varies. Hence, a distorted reflection pattern results (see Fig. 20-2).

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Page 20 NivuFlow Stick - rev. 00 / 27.01.2020
Fig. 20-2 Situation at second signal detection
The DSP checks both received reflection patterns for similarities using the cross correlation
method. All existing signal differences (caused by new or rotated particles) are rejected so
that two similar but temporarily offset signal patterns are left for velocity evaluation.
Depending on the flow levels both patterns are subdivided into 16 measurement windows.
Fig. 20-3 Echo signal images and evaluation
Based on the beam angle, the interval between both transmitted signals and the shift of the
signal pattern therefore in each single measurement window the flow velocity can be deter-
mined.
It mathematically strings the single flow velocities together which results in the flow profile of
the acoustic path.
This measured velocity profile is directly indicated on the NivuFlow Stick display (Fig. 20-4
pict. 1). Clicking the graph will switch over to lateral profile view (Fig. 20-4 pict. 2).
Fig. 20-4 Determined flow profile