HyQuest Solutions WLR 8 User manual

WLR 8/15/30
User Manual

© 2022 HyQuest Solutions 2
Table of Contents
Disclaimer 3I
II Glossary + Abbreviations 4
III Safety Instructions 5
Part I Introduction 6
Part II Installation 7
2.1 Rain and Wind ................................................................................................................................................... 8
2.2 Interference and Multiple Radars ............................................................................................................... 8
2.3 Interference with Fog and Evaporation .................................................................................................... 9
2.4 Reflections ......................................................................................................................................................... 9
Part III Configuration (formerly Radar Configurator Utility) 10
Part IV Repair 12
Part V Technical Data (formerly Electrical Characteristics) 13
Part VI Obligations of the Operator and Disposal 14
6.1 Obligations of the Operator ....................................................................................................................... 14
6.2 Dismantling / Disposal ................................................................................................................................ 14
Part VII Appendices 16
7.1 Connector Pin-Out ......................................................................................................................................... 17
7.1.1 SDI-12 Interface ..................................................................................................................................... 19
7.1.2 Serial RS-485 Interface ........................................................................................................................ 19
7.1.3 Serial RS-232 Interface ........................................................................................................................ 19
7.1.4 Analogue 4-20 mA Output ................................................................................................................... 19
7.2 Data Interface ................................................................................................................................................ 20
7.2.1 SDI-12 ........................................................................................................................................................ 20
7.2.2 Serial RS-485 Interface ........................................................................................................................ 21
7.3 Data Protocols ................................................................................................................................................ 21
7.3.1 SDI-12 protocol ....................................................................................................................................... 21
7.3.2 Servicing protocol (RS-232) ................................................................................................................ 24
7.3.3 Modbus RTU protocol (RS-485) .......................................................................................................... 26
7.4 Mechanical Drawing ..................................................................................................................................... 33

Copyright Notice: No parts of this work may be
reproduced in any form or by any means without the
written permission of the publisher. HyQuest
Solutions waives copyright for users to print out
parts of the documentation in hard copy for their
own use only.
Trademark Notice: HyQuest Solutions (HS) and
KISTERS products and services referred to in this
document are trademarks or registered trademarks
of HyQuest Solutions or KISTERS AG. Other product
names used may or may not be the trademarks of
their respective owners.
© 2020 HyQuest Solutions, a KISTERS Group
Company. Any rights not expressly granted herein
are reserved.
The information provided in this manual was deemed
accurate as of the publication date. However, updates
to this information may have occurred.
This manual does not include all of the details of
design, production, or variation of the equipment
nor does it cover every possible situation which may
arise during installation, operation or maintenance.
HyQuest Solutions shall not be liable for any
incidental, indirect, special or consequential damages
whatsoever arising out of or related to this
documentation and the information contained in it,
even if HyQuest Solutions has been advised of the
possibility of such damages.
Any errors found in any HyQuest Solutions product
should be reported to HyQuest Solutions where
every effort will be made to quickly resolve the
problem.
This document is public.
3© 2022 HyQuest Solutions
I Disclaimer

II Glossary + Abbreviations
Term
Definition
See antenna 3 dB beam width
Antenna 3 dB Beam
Width
also known as the half-power; the angle between the half-power of an antenna pattern or
beam over which the relative power is at or above 50% of the peak power
bps
bits per second, a measure for data transmission speed
CWFM Radar
continuous-wave frequency-modulated radar
Dead Zone
Equivalent to blocking distance or dead band, defines the minimum distance between water
surface and sensor antenna that is needed to measure precisely (a function of the radio wave
frequency)
ERP
Effective Radiation Power, IEEE standard definition of directional radiofrequency (RF) power
EIRP
Equivalent Isotropically Radiation Power, hypothetical power of an isotropic antenna with
equivalent signal strength of the actual source antenna in the direction of the strongest beam
GHz
See Hz
Hz
(GHz)
International Standard System of Units derived unit of frequency, Hertz (symbol: Hz)
GHz: a gigahertz is the multiple of the hertz frequency equivalent to 109Hz
GND
Ground, electrical ground or signal ground
Mx, Mxx
ISO standard for metric screw threads w/ M=metric, x or xx = outer diameter in millimeters
RF
Radio Frequency
RxD
Data reception line
TxD
Data transmission line
W Band
Frequency band in the microwave range of the electromagnetic spectrum, typically 75..110
GHz
WLR 8/15/30
Water Level Radar w/ measurement range relative to water surface of
§
8 m (26,24 ft)
§
15 m (49,2 ft)
§
30 m (98,4 ft)
4© 2022 HyQuest Solutions

§
Read the user manual including all operating instructions prior to installing, connecting and powering up the HyQuest
Solutions WLR 8/15/30. The manual provides information on how to operate the product. The manual is intended to
be used by qualified personnel, i.e. personnel that have been adequately trained, are sufficiently familiar with
installation, mounting, wiring, powering up and operation of the product.
§
Keep the user manual on hand for later reference!
§
If you encounter problems understanding the information in the manual (or part thereof), please consult the
manufacturer or its appointed reseller for further support.
§
HyQuest Solutions WLR 8/15/30 is intended to be used in hydrometeorological or environmental monitoring
applications.
§
Before starting to work, you have to check the functioning and integrity of the system.
§
Check for visible defects on the WLR 8/15/30, this may or may not include any or all of the following mounting
facilities, connectors and connections, mechanical parts, internal or external communication devices, power
supplies or power supply lines, etc.
§
If defects are found that jeopardize the operational safety, work must be stopped. This is true for defects found
before starting to work as well as for defects found while working.
§
Do not use the HyQuest Solutions WLR 8/15/30 in areas where there is a danger of explosion.
§
The present user manual specifies environmental/climatic operating conditions as well as mechanical and electrical
conditions. Installation, wiring, powering up and operating the HyQuest Solutions WLR 8/15/30 must strictly comply
with these specifications.
§
Perform maintenance only when tools or machinery are not in operation.
§
If guards are removed to perform maintenance, replace them immediately after servicing.
§
Never make any electrical or mechanical diagnostics, inspections or repairs under any circumstances. Return the
sensor to the manufacturer’s named repair centre. You can find information on how to return items for repair in the
relevant section of the HyQuest Solutions web site.
§
Disposal instructions: After taking the HyQuest Solutions WLR 8/15/30 out of service, it must be disposed of in
compliance with local waste and environmental regulations. The HyQuest Solutions WLR 8/15/30 is never to be
disposed in household waste!
§
Inputs and outputs of the device are protected against electric discharges and surges (so-called ESD). Do not
touch any part of the electronic components! If you need to touch any part, please discharge yourself, i.e. by touching
grounded metal parts.
Specific Safety Instructions
§
The manual provides information on how to operate the sensor system.
§
Protect the power supply connection with a fuse (2.5 A fast blow fuse). For cable length exceeding 40 m (131.2 ft),
surge protection shall be integrated.
§
Please refer to the EIRP power listed in this manual. Note that the main orientation of the sensor is: downward-looking
with the core radar beam oriented downwards, installation location must be chosen to avoid the beam is oriented
towards living species. The device is designed for use in fixed installation. Mobile applications are not within the scope
of the sensor.
§
European Union and European Economic Area: The national implementation of the framework directive 89/391/EEC
and corresponding individual directives, in particular the directive 2009/104/EEC concerning the minimum safety and
health requirements for the use of work equipment by workers at work (incl. amendments) must at all times be
observed and adhered to.
§
USA-FCC Approval: The equipment has been tested and found compliant with specifications and limits of Class A digital
devices, pursuant to Article 15 of FCC rules. FCC limits ensure electromagnetic compatibility, i.e. a design providing
reasonable protection against electromagnetic interference. The HyQuest Solutions WLR 8/15/30 is a device emitting
radio frequency. It must be installed and operated in compliance with the User Manual. Non-respect of the stipulations
of the manual may result in interference with radio communication devices. When installed in developed areas, a risk
of harmful interference exists and it is up to the user to provide necessary measures to limit these interferences at his
own expense. Respect of Local Legislation: Users must confirm with local legislation. This may or may not include the
need to apply and obtain a permission to install a radar sensor. In such a case all provisions of the permission must be
observed by the user. Other local/national legislation that must be observed where required concerns any or all of the
following topics: safety at work and personnel safety, environmental protection, health issues, electromagnetic
compatibility, waste (disposal of products and materials).
III Safety Instructions
© 2022 HyQuest Solutions 5

© 2022 HyQuest Solutions 6
Introduction
1Introduction
Thank you for choosing our product. We hope you will enjoy using the device.
HyQuest Solutions manufactures, sells, installs and operates quality instrumentation, data loggers and communication
technology. Products are designed with passion for environmental monitoring and with a deep understanding of the
quality, accuracy and robustness needed to fulfil the requirements of measurement practitioners in the field.
The present User Manual will help you understand, install and deploy the device. If, however, you feel that a particular
information is missing, incomplete or confusing, please do not hesitate to contact us for further support!
HyQuest Solutions’ WLR 8/15/30 is a highly accurate radar level sensor that measures the distance from the sensor to the
surface. It uses advanced 80 GHz radar technology to provide accurate and stable measurements. Using contactless
technology for measurement of level of fluids and solids provides many advantages over traditional methods due to
simple installation, low power consumption and minimal to no maintenance.

© 2022 HyQuest Solutions 7
Installation
2Installation
The level meter must be installed above the water surface, pointing directly towards the water surface. Please read the
following carefully and respect these instructions and recommendations as much as possible to obtain the best
measurement results.
§
Minimum Installation Height above Water Surface: 0.1 m (0.33 ft), recommended > 1 m (3.28 ft)
§
Maximum Installation Height above Water Surface: <= max measurement range of the device
§
Sensor should be directed at a 90° angle towards the water.
Caution:
§
Direct non-obstructed line of sight between sensor antenna and the water surface
§
Avoid object in the vicinity of the sensor: may reduce accuracy, introduce offsets
§
Reduce vibrations of the mounting structure: affects measurements
§
Ensure water surface direct below the sensor is clear of: vegetation, rocks, sand deposition, other obstacles.
§
The sensor applies an algorithmic correction to detect and eliminate obstacles from the distance measurement
signal spectrum. However, the correction has limits. Vibrations can further limit the effectiveness of the algorithm.
The figure below shows how the radar should be positioned relative to the water surface.
Figure 1 – Water Level Radar (WLR) Installation
The height measurement works best when water surface is calm (not too wavy) as flat surfaces better reflect radar beams.
In applications with continuous/frequent highly turbulent water, the length of the radar filter can be adjusted to filter out
most, if not all the turbulences.
§
Slight up to moderate surface waviness will affect reflected signal level (reducing Signal to Noise Ratio SNR), but is
unlikely to affect measurement accuracy.
§
Strong turbulent flow with high water waviness will reduce accuracy due the unpredictability of the water surface. The
averaging effect across the area covered by the radar beam will reduce oscillations.
Instrument radar beam covers a circular area on the water surface. The radar beam has a 3-dB width angle, subsequently
the diameter of the pattern on the water surface depends on the distance of the water surface to the instrument. See
Table 3 for pre-calculated pattern dimension.

© 2022 HyQuest Solutions 8
Installation
Height [H]
R
|
Height [H]
R
0.3 m (0.33 ft)
0.06 m (0.2 ft)
|
9 m (29.52 ft)
1.89 m (6.2 ft)
0.5 m (1.64 ft)
0.11 m (0.36 ft)
|
10 m (32.8 ft)
2.10 m (6.89 ft)
1 m (3.28 ft)
0.21 m (0.69 ft)
|
11 m (36.08 ft)
2.31 m (7.58 ft)
2 m (6.56 ft)
0.42 m (1.38 ft)
|
12 m (39.36 ft)
2.52 m (8.27 ft)
3 m (9.84 ft)
0.63 m (2.07 ft)
|
13 m (42.64 ft)
2.73 m (8.95 ft)
4 m (13.12 ft)
0.84 m (2.76 ft)
|
14 m (45.92 ft)
2.94 m (9.64 ft)
5 m (16.4 ft)
1.05 m (3.44 ft)
|
15 m (49.2 ft)
3.15 m (10.33 ft)
6 m (19.68 ft)
1.26 m (4.13 ft)
|
20 m (65.6 ft)
4.20 m (13.78 ft)
7 m (22.96 ft)
1.47 m (4.82 ft)
|
25 m (82 ft)
5.25 m (17.22 ft)
8 m (26.24 ft)
1.68 m (5.51 ft)
|
30 m (98.4 ft)
6.30 m (20.66 ft)
Table 1 – Approximated Height-Dependent Circular Radar Beam Pattern Dimension (Water Surface)
§
Rain and Wind
§
Interference and Multiple Radars
§
Interference with Fog and Evaporation
§
Reflections
2.1 Rain and Wind
WLR 8/15/30 instruments has integrated internal software filters to filter out effects of rain, fog or wind for radar
distance sensor. These filters however have some limitations. Majority of measurement inaccuracies caused by
environmental factors can be solved by proper sensor installation.
For rain and snow suppression, the most effective solution is to mount the radar so that it points directly at water. As rain
or snow fall, they affect the water surface, so it isn’t as reflective as usually, thus reducing the SNR. However, our devices
are tested and calibrated in a way, so they detect the surface even under heavy rainfall.
Influence of the wind on the accuracy is in most cases small and can be neglected. The only exception is strong wind as it
will create surface waves and turbulences which can be detected as a shift in level. As mentioned above, length of radar
filter can be adjusted to compensate for this.
2.2 Interference and Multiple Radars
Distance measurement radar is operating in W-band from 77 GHz to 81 GHz with linear frequency modulation,
modulating signal continuously in the mentioned frequency range. To get interference between two or more sensors it
will be required to keep central frequencies very precise just like in surface velocity radar and additionally timing
synchronization of radar should be kept in range of 25 ns to each other. Such synchronization is very complex to achieve
so the interference probability between several radars on the same location is very small.
It is possible that some wideband radiation sources can introduce small and impulse interference for the short period of
time, but this should not, or it is very unlikely to affect measurements reported by radar sensor.
8
8
9
9

© 2022 HyQuest Solutions 9
Installation
2.3 Interference with Fog and Evaporation
Generally, radar sensors are not affected by fog or evaporation of water unless very heavy evaporation is present and
water density in the air is very high.
The best solution for the distance measurement is in most cases to increase average period to get better average distance
value. As evaporation is naturally very turbulent event with significant difference in density over the surface area and in
time, averaging of the distance measurement spectrum is solving the problem of accuracy in such conditions.
2.4 Reflections
Water is very reflective medium for the radar waves and most of the power transmitted from radar transmitter will be
reflected from the water surface. Reflections of the radar transmitted power beam follow the same physical laws as in
optics and every time radar beam hits the surface part of the power is reflected away from the radar, part of the power is
reflected towards the radar and only a small part of power is absorbed by the water. Depending on the surface
roughness and incident angle ratio between power reflected in the direction away from the radar and direction back
towards the radar can significantly vary. As incident angle for radars in fixed, only the roughness is determining the
ration in our case.
In the case of level meter where incident angle of transmitted radar beam to the water is around 90° most of the power is
reflected to the sensor and only small portion of the transmitter power will be dispersed in all directions. Ratio between
power reflected to the sensor and power dispersed in all directions is dependent on the surface roughness but in general
it is very small amount of the energy that is dispersed, and it is very unlikely that dispersed energy will cause additional
multipath problems due to the more reflections from surrounding objects.

© 2022 HyQuest Solutions 10
Configuration (formerly Radar Configurator Utility)
3Configuration (formerly Radar Configurator Utility)
HyQuest Solutions provides a user-friendly PC application to configure WLR Water Level Radars. Additionally, the
Configurator Utility displays current level readings.
When started, the Configurator Utility displays its main window. Initially, no level data is displayed, as the connection to
the level meter device is not established.
Figure 2 – Level Meter Configurator main window
To connect the Configurator utility with the level meter, connect your PC to the radar using an RS-232 serial cable
connection. Then, select the Radar à Connect menu option in the Configurator Utility, and choose the appropriate COM
port number. The Configurator will try to establish a data link between your PC and the level meter device. After the data
link is established, active device parameters will be displayed, and the level measurements will be displayed:
Figure 3 – Configurator main window with device connected
The utility window is divided into two panes, that can be manually re-arranged. The first panel (at the left part of the
screen) is the Radar Module Info pane that displays the radar level meter information and operating parameters. Some of
these parameters can be changed by editing the values directly inside the Radar Module Info pane. The following
information is displayed:
Firmware version
the version of the firmware running in the radar sensor
device
Level correction
correction in meters to be added to the detected level
Dead zone minimum
minimum detected distance

© 2022 HyQuest Solutions 11
Configuration (formerly Radar Configurator Utility)
Dead zone maximum
maximum detected distance
Filter length
if moving average filter is used, select the averaging
window length
Amplitude threshold
minimum spectrum amplitude necessary for peak
detection
RX gain
the current gain value of the radar signal amplifier
IR constant
if IR is used, this value is used for the IR filter
Serial baud rate
the communication baud rate used for serial
communication
RS485 baud rate
the communication baud rate used for RS485
communication
RS485 parity
parity used on the RS485 bus
RS485 stop bits
stop bits used on the RS485 bus
Modbus address
device address on the RS485 bus
Water level
water level in meters
Average water level
average water level in meters, using filter length
The second pane (in the right part of the window) displays the history graph showing the measured level in the last 30
minutes.

© 2022 HyQuest Solutions 12
Repair
4Repair
HyQuest Solutions precision instruments and data loggers are produced in quality-controlled processes. All HyQuest
Solutions production and assembly sites in Australia, New Zealand and Europe are ISO 90001 certified. All equipment is
factory tested and/or factory calibrated before it is shipped to the client. This ensures that HyQuest Solutions products
perform to their fullest capacity when delivered.
Despite HyQuest Solutions most rigorous quality assurance (QA), malfunction may occur within or outside of the warranty
period. In rare cases, a product may not be delivered in accordance with your order.
In such cases HyQuest Solutions’ return and repair policy applies. For you as a customer, this means the following:
1. Contact HyQuest Solutions using the Repair Request Form made available online:
https://www.hyquestsolutions.eu/fileadmin/Form/Telemetry_Solution_app.jpg.pdf
In response you will receive a reference number that must be referenced on all further correspondence and on the
freight documents accompanying your return shipment.
2. Please provide as much information and/or clear instructions within the return paperwork. This will assist our test
engineers with their diagnosis.
3. Please do not ship the goods prior to obtaining the reference number. HyQuest Solutions will not reject any
equipment that arrives without reference number; however, it may take us longer to process.
Custom requirements for items sent to HyQuest Solutions for warranty or non-warranty repairs: Check with your
national customs/tax authorities for details, processes and paperwork regarding tax exempt return of products. Typically,
special custom tariff codes are available (such as HS Code = 9802.00) that verify the item is being returned for repair and
has no commercial value. Please note that the customs invoice / dispatch documents should also clearly state: “Goods
being returned to manufacturer for repair – No Commercial value”. It is mandatory to have any returned goods
accompanied by a commercial invoice on headed paper. HyQuest Solutions reserves the right to charge the customer for
time spent rectifying incorrect customs documents.
Note: Please ensure that your goods are packed carefully and securely. Damage that occurs during transit is not covered
by our warranty and may be chargeable.

© 2022 HyQuest Solutions 13
Technical Data (formerly Electrical Characteristics)
5Technical Data (formerly Electrical Characteristics)
WLR 8
WLR 15
WLR 30
Detection Distance
8 m
15 m
30 m
Radar Type
W-band 77-81 GHz FMCW radar
Beam Angle
12° both axes
Blind Zone
0.2 m
Resolution
0.2 m
Accuracy
± 3 mm
IP Rating
IP68
Interfaces
§
SDI-12
§
Analog: 4 - 20 mA
§
Serial Interface:
§
1 × serial RS-485 half-duplex, 1 × serial RS-232 (two-wire interface)
§
Serial Baud Rate: 1200 bps to 115200 bps
§
Serial Protocols: Modbus
Connector
M12 circular 12-pin
Power Supply
Power Input: 9 to 27 V DC
Power Consumption: <2.2 W (typical 1.8 W)
Temperature Range
Operational temperature: -40 °C to +85 °C (without heating or coolers)
Enclosure Dimensions
Ø 65 mm × H 55 mm
Compliance
FCC, CE

© 2022 HyQuest Solutions 14
Obligations of the Operator and Disposal
6Obligations of the Operator and Disposal
This chapter contains the following subsections:
§
Obligations of the Operator
§
Dismantling / Disposal
6.1 Obligations of the Operator
European Union
In the Single European Market it is the responsibility of the operator to ensure that the following legal regulations are
observed and complied with: national implementation of the framework directive (89/391/EEC) and the associated
individual directives, in particular 2009/104/EC, on minimum safety and health requirements for the use of work
equipment by employees at work.
Worldwide
Regulations: If and where required, operating licences must be obtained by the operator. In addition, national or regional
environmental protection requirements must be complied with, regardless of local legal provisions regarding the
following topics:
§
Occupational safety
§
Product disposal
Connections: Local regulations for electrical installation and connections must be observed.
6.2 Dismantling / Disposal
When disposing of the units and their accessories, the applicable local regulations regarding environment, disposal and
occupational safety must be observed.
Before dismantling
§
Electrical Devices:
§
Switch off the units.
§
Disconnect electrical appliances from the power supply, regardless of whether the appliances are connected to the
mains or to another power source.
§
Mechanical devices:
§
Fix all loose components. Prevent the device from moving independently or unintentionally.
§
Loosen mechanical fastenings: Please note that appliances can be heavy and that loosening the fastenings may cause
them to become mechanically unstable.
Disposal
Operators of old appliances must recycle them separately from unsorted municipal waste. This applies in particular to
electrical waste and old electronic equipment.
Electrical waste and electronic equipment must not be disposed of as household waste!
Instead, these old appliances must be collected separately and disposed of via the local collection and return systems.
Integrated or provided batteries and accumulators must be separated from the appliances and disposed of at the
designated collection point.
14
14

© 2022 HyQuest Solutions 15
Obligations of the Operator and Disposal
EU WEEE Directive
As players in the environmental market, KISTERS AG and HyQuest Solutions are committed to supporting efforts to avoid
and recycle waste. Please consider:
Avoidance before recycling!
Recycling before disposal!
This symbol indicates that the scrapping of the unit must be carried out in accordance with Directive 2012/19/EU.
Please observe the local implementation of the directive and any accompanying or supplementary laws and regulations.

© 2022 HyQuest Solutions 17
Appendices
7.1 Connector Pin-Out
The level meter uses robust IP66 circular M12 connector with 12 positions and the mating cable is also delivered with the
level meter. See the figure below for connector and cable details.
Figure 4 – Level meter connectors
The table below shows pin assignments for each single pin of the connector illustrated in the figure above.

© 2022 HyQuest Solutions 18
Appendices
Pin No.
Wire Color
Pin Name
Pin Description
1
White
GND
This pin should be
connected to the
ground (negative) pole
of the power supply.
SDI-12 Ground
2
Brown
+Vin
WLR supply power
Voltage range 9..27
VDC, power supply >=
2.2 W
SDI-12 Power
3
Green
RS232 – TxD
RS-232 data transmit
signal
4
Yellow
RS232 – RxD
RS-232 data receive
signal
5
Grey
---
-----
6
Pink
---
-----
7
Blue
---
-----
8
Red
Vout+
Output power supply
(=Vin) for supply of
external optional
equipment and for use
with analogue 4-20mA
output
9
Orange
RS485 – D-
RS-485 data
transmitter/receiver
low signal
10
Dark Red
RS485 – D+
RS-485 data
transmitter/receiver
high signal
11
Black
SDI-12 Data
SDI-12 Data Line
12
Purple
4-20 mA Output
Analogue 4-20 mA
output
Table 2 – Connector and cable pin-out
§
SDI-12 Interface
§
Serial RS-485 Interface
§
Serial RS-232 Interface
§
Analogue 4-20 mA Output
19
19
19
19

© 2022 HyQuest Solutions 19
Appendices
7.1.1 SDI-12 Interface
SDI-12 interface is widely used communication interface in hydrology applications. Such interface is characterized with
only one communication wire, slow speed communication and possibility for very long communication cables.
The implemented command set is compliant with SDI-12, Version 1.3 (even though not all commands are fully
implemented).
Caution: Differences with SDI-12 sensors
§
The Water Level Radar (WLR) is a high-frequency device. The slowest scan rate is 1 sample/sec (1 Hz). A faster version
is available with a scan rate of 10 samples/sec (Hz).
§
The supply voltage is higher than the standard 5V requirement of the standard.
§
The power consumption is higher.
7.1.2 Serial RS-485 Interface
Serial RS-485 interface is implemented as standard industrial half-duplex communication interface. Communication
interface is short-circuited and overvoltage internally protected. Depending on the receiving device interface can be used
with only two wires (D+ dark red wire & D- orange wire) or in some cases ground connection (signal GND grey wire) is also
required. For more details please consult receiver specifications.
Most common communication protocol used with RS-485 interface is Modbus-RTU, but other protocols are also available.
Details of communication protocols are described later in this manual.
7.1.3 Serial RS-232 Interface
Serial RS-232 interface is implemented as standard PC full-duplex serial interface with voltage levels adequate for direct
connection to PC computer or other embedded device used for serial RS-232 communication.
In case RS-232 interface is connected to standard DB-9 PC connector, TxD line (green wire) is connected to pin 2 and RxD
(yellow wire) is connected to pin 3. For proper operation of serial interface additional connection of signal GND (grey wire)
is required on pin 5 of the DB-9 connector.
The serial RS-232 interface is used as a service port. For more details see Servicing protocol (RS-232) .
Option – on order: HyQuest Solutions can supply cable with DB-9 connector connected to the cable.
7.1.4 Analogue 4-20 mA Output
Analogue current 4-20 mA output is provided for easier compatibility with older logging and control systems. Output is
implemented as current sink architecture with common ground. Maximal voltage applied to the sink can go up to 30 VDC
providing greater flexibility in connection of the sensor to PLCs, loggers, or data concentrators.
Signal range and function for 4-20 mA analogue output can be configured in setup application so the sensor will be able
to signal best suitable value range with available current range. Current step in the sensor is 0.3 µA limiting resolution
possible for the value signalling and care has to be taken in the setup of minimal value to be represented by 4 mA and
maximal value to be represented by 20 mA, so the resolution is sufficient for the system requirements.
24

© 2022 HyQuest Solutions 20
Appendices
Figure 5 – Schematics 4-20 mA Output
7.2 Data Interface
WLR 8/15/30 Water Level Radars are equipped with serial data interfaces.
Interfaces available on WLR Water Level Radars are compatible with HyQuest Solutions iRIS Data Loggers, and many
third-party data loggers.
·
SDI-12
·
Serial RS-485 Interface
7.2.1 SDI-12
Serial SDI-12 is the preferred interface in many hydrometeorological applications. Multiple Water Level Radars can be
connected via SDI-12 to a single data logger. Level measurements are not reported automatically, but are reported only
after being requested by the master device (data logger unit). WLR 8/15/30 implements a sub-set of the SDI-12 Version
1.3 command set. Detailed description of the protocol is given in the Chapter 6 of this User manual.
Default communication parameters are:
Bitrate:
1200 bps
Start bits:
1
Data bits:
7
Stop bits:
1
Parity:
Even
20
21
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