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LDDS20 LoRaWAN Liquid Level Sensor User Manual 1 / 20
LoRaWAN Liquid Level Sensor User Manual
Document Version: 1.1
Image Version: v1.0
Version
Description
Date
1.0
Release
2020-Aug-08
1.1
Add different hardware UART Connection photo
2020-Nov-5
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1. Introduction 3
1.1 What is LoRaWAN Ultrasonic liquid level sensor 3
1.2 Features 4
1.3 Suitable Container & Liquid 4
1.4 Mechanical 4
1.5 Install LDDS20 5
1.6 Applications 6
1.7 Precautions 6
2. Configure LDDS20 to connect to LoRaWAN network 7
2.1 How it works 7
2.2 Quick guide to connect to LoRaWAN server (OTAA) 7
2.3 Uplink Payload 10
2.3.1 Battery Info 10
2.3.2 Liquid height 10
2.3.3 Decode payload in The Things Network 10
2.4 Downlink Payload 11
2.5 Show Data in Mydevices IoT Server 12
2.6 LED Indicator 13
2.7 Firmware Change Log 14
2.8 Battery Analysis 14
2.8.1 Battery Type 14
2.8.2 Power consumption Analyze 14
2.8.3 Battery Note 14
2.8.4 Replace the battery 15
3. Using the AT Commands 16
3.1 Access AT Commands 16
4. FAQ 19
4.1 What is the frequency plan for LDDS20? 19
4.2 How to change the LoRa Frequency Bands/Region? 19
5. Trouble Shooting 19
5.1 Why I can’t join TTN in US915 / AU915 bands? 19
5.2 AT Command input doesn’t work 19
6. Order Info 20
7. Packing Info 20
8. Support 20
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1. Introduction
1.1 What is LoRaWAN Ultrasonic liquid level sensor
The Dragino LDDS20 is a LoRaWAN Ultrasonic liquid level sensor for Internet of Things
solution. It uses none-contact method to measure the height of liquid in a container without
opening the container, and send the value via LoRaWAN network to IoT Server
The LDDS20 sensor is installed directly below the container to detect the height of the liquid
level. User doesn’t need to open a hole on the container to be tested. The none-contact
measurement makes the measurement safety, easier and possible for some strict situation.
LDDS20 uses ultrasonic sensing technology for distance measurement. LDDS20 is of high
accuracy to measure various liquid such as: toxic substances, strong acids, strong alkalis and
various pure liquids in high-temperature and high-pressure airtight containers.
The LoRa wireless technology used in LDDS20 allows device to send data and reach
extremely long ranges at low data-rates. It provides ultra-long range spread spectrum
communication and high interference immunity whilst minimizing current consumption.
LDDS20 is powered by 8500mA Li-SOCI2 battery; It is designed for long term use up to 10
years*.
Each LDDS20 pre-loads with a set of unique keys for LoRaWAN registrations, register these
keys to local LoRaWAN server and it will auto connect if there is network coverage, after
power on.
*Actually lifetime depends on network coverage and uplink interval and other factors
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1.2 Features
LoRaWAN 1.0.3 Class A
Ultra low power consumption
Liquid Level Measurement by Ultrasonic technology
Measure through container, No need to contact Liquid.
Valid level range 20mm - 2000mm
Accuracy: ±(5mm+S*0.5%) (S: Measure Value)
Cable Length : 25cm
Bands: CN470/EU433/KR920/US915/EU868/AS923/AU915/IN865
AT Commands to change parameters
Uplink on periodically
Downlink to change configure
IP66 Waterproof Enclosure
8500mAh Battery for long term use
1.3 Suitable Container & Liquid
Solid Wall container such as: steel, iron, glass, ceramics, non-foaming plastics etc.
Container shape is regular, and surface is smooth.
Container Thickness:
✓ Pure metal material. 2~8mm, best is 3~5mm
✓ Pure non metal material: <10 mm
Pure liquid without irregular deposition.
1.4 Mechanical
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1.5 Install LDDS20
Step 1: Choose the installation point.
LDDS20 is installed on the container bottom
middle position.
Step 2: Polish the installation point.
For Metal Surface with paint, it is important to
polish the surface, first use crude sand paper to
polish the paint level , then use exquisite sand
paper to polish the metal level to make it shine &
smooth. .
No polish needed if the container is shine metal
surface without paint or non-metal container.
Step3: Test the installation point.
Power on LDDS75, check if the blue LED is on, If the
blue LED is on, means the sensor works. Then put
ultrasonic coupling paste on the sensor and put it
tightly on the installation point.
Then push the reset button on LDDS20 and see if
the BLUE LED is slowly blinking. If the LED is slowly
blinking, it means this installation point is good.
Note 1:
➢ BLUE LED always ON: Sensor is power on but doesn’t detect liquid.
➢ BLUE LED slowly blinking: Sensor detects Liquid Level.
LDDS20 will enter into low power mode at 30 seconds after system reset or power on,
Blue LED will be off after that.
Note 2:
Ultrasonic coupling paste is subjected in most shipping way. So the default package doesn’t
include it and user needs to purchase locally.
Metal Surface with paint needs polish
Shine Metal Surface without
paint no need polish
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Step4: Install use Epoxy ab glue.
Prepare Eproxy AB glue.
Put Eproxy AB glue in the sensor and press it hard on
the container installation point.
Reset LDDS20 and see if the BLUE LED is slowly
blinking.
Note1:
Eproxy AB glue needs 3~ 5 minutes to stable
attached. we can use other glue material to
keep it in the position.
Note 2:
Eproxy AB glue is subjected in most shipping
way. So the default package doesn’t include it
and user needs to purchase locally.
1.6 Applications
Smart liquid control solution.
Smart liquefied gas solution.
1.7 Precautions
At room temperature, containers of different materials, such as steel, glass, iron,
ceramics, non-foamed plastics and other dense materials, have different detection blind
areas and detection limit heights.
For containers of the same material at room temperature, the detection blind zone and
detection limit height are also different for the thickness of the container.
When the detected liquid level exceeds the effective detection value of the sensor, and
the liquid level of the liquid to be measured shakes or tilts, the detected liquid height is
unstable.
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2. Configure LDDS20 to connect to LoRaWAN network
2.1 How it works
The LDDS20 is configured as LoRaWAN OTAA Class A mode by default. It has OTAA keys to
join LoRaWAN network. To connect a LoRaWAN network, you need to input the OTAA keys
in the LoRaWAN IoT server and power on the LDDS20. If there is coverage of the LoRaWAN
network, it will automatically join the network via OTAA and start to send the sensor value
In case you can’t set the OTAA keys in the LoRaWAN OTAA server, and you have to use the
keys from the server, you can use AT Commands to set the keys in the LDDS20.
2.2 Quick guide to connect to LoRaWAN server (OTAA)
Following is an example for how to join the TTN LoRaWAN Network. Below is the network
structure; we use the LG308 as a LoRaWAN gateway in this example.
The LG308 is already set to connected to TTN network , so what we need to now is configure
the TTN server.
Step 1: Create a device in TTN with the OTAA keys from LDDS20.
Each LDDS20 is shipped with a sticker with the default device keys, user can find this sticker
in the box. it looks like below.
For OTAA registration, we need to set APP EUI/ APP KEY/ DEV EUI. Some server might no
need to set APP EUI.
Enter these keys in the LoRaWAN Server portal. Below is TTN screen shot:
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Add APP EUI in the application
Add APP KEY and DEV EUI
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Step 2: Power on LDDS20
Put a Jumper on JP2 to power on the device. ( The switch must be set in FLASH position).
Step 3: The LDDS20 will auto join to the TTN network. After join success, it will start to
upload messages to TTN and you can see the messages in the panel.
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2.3 Uplink Payload
LDDS20 will uplink payload via LoRaWAN with below payload format:
Uplink payload includes in total 4 bytes.
2.3.1 Battery Info
Check the battery voltage for LDDS20.
Ex1: 0x0B45 = 2885mV
Ex2: 0x0B49 = 2889mV
2.3.2 Liquid height
Get the distance. Flat object range 20mm - 2000mm.
For example, if the data you get from the register is 0x06 0x05, the distance between the
sensor and the measured object is
0605(H) = 1541 (D) = 1541 mm.
If the sensor value is 0x0000, it means system doesn’t detect ultrasonic sensor.
If the sensor value lower than 0x0014 (20mm), the sensor value will be invalid.
2.3.3 Decode payload in The Things Network
While using TTN network, you can add the payload format to decode the payload.
Size
(bytes)
2
2
Value
BAT
Liquid height(unit: mm)
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The payload decoder function for TTN is here:
LDDS20 TTN Payload Decoder:
http://www.dragino.com/downloads/index.php?dir=LoRa_End_Node/LDDS20/Payload_Dec
oder/
2.4 Downlink Payload
By default, LDDS20 prints the downlink payload to console port.
Downlink Control Type
FPort
Type Code
Downlink payload size(bytes)
TDC (Transmit Time Interval)
Any
01 4 RESET
Any
04 2 AT+CFM
Any
05 4 INTMOD
Any
06
4
Examples
Set TDC
If the payload=0100003C, it means set the END Node’s TDC to 0x00003C=60(S), while type
code is 01.
Payload: 01 00 00 1E TDC=30S
Payload: 01 00 00 3C TDC=60S
Reset
If payload = 0x04FF, it will reset the LDDS20
CFM
Downlink Payload: 05000001, Set AT+CFM=1 or 05000000 , set AT+CFM=0
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2.5 Show Data in Mydevices IoT Server
Mydevices provides a human friendly interface to show the sensor data, once we have data
in TTN, we can use Mydevices to connect to TTN and see the data in Mydevices. Below are
the steps:
Step 1: Be sure that your device is programmed and properly connected to the network at
this time.
Step 2: To configure the Application to forward data to Mydevices you will need to add
integration. To add the Mydevices integration, perform the following steps:
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Step 3: Create an account or log in Mydevices.
Step 4: Search the LDDS75 and add DevEUI. (Note: LDDS20 use same payload as LDDS75)
After added, the sensor data arrive TTN, it will also arrive and show in Mydevices.
2.6 LED Indicator
The LDDS20 has an internal LED which is to show the status of different state.
➢ Blink once when device power on.
➢ The device detects the sensor and flashes 5 times.
➢ Solid ON for 5 seconds once device successful Join the network.
➢ Blink once when device transmit a packet.
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2.7 Firmware Change Log
Firmware download link:
http://www.dragino.com/downloads/index.php?dir=LoRa_End_Node/LSE01/Firmware/
Firmware Upgrade Method:
http://wiki.dragino.com/index.php?title=Firmware_Upgrade_Instruction_for_STM32_base_
products#Introduction
2.8 Battery Analysis
2.8.1 Battery Type
The LDDS20 battery is a combination of a 8500mAh Li/SOCI2 Battery and a Super Capacitor.
The battery is non-rechargeable battery type with a low discharge rate (<2% per year). This
type of battery is commonly used in IoT devices such as water meter.
The battery is designed to last for more than 10 years for the LDDS20.
The battery related documents as below:
● Battery Dimension,
● Lithium-Thionyl Chloride Battery datasheet
● Lithium-ion Battery-Capacitor datasheet,
2.8.2 Power consumption Analyze
The file DRAGINO_LDDS20-Power-Analyzer.pdf from
http://www.dragino.com/downloads/index.php?dir=LoRa_End_Node/LDDS20/ describes a detail
measurement to analyze the power consumption in different case. User can use it for design
guideline for their project.
2.8.3 Battery Note
The Li-SICO battery is designed for small current / long period application. It is not good to
use a high current, short period transmit method. The recommended minimum period for
use of this battery is 5 minutes. If you use a shorter period time to uplink data, then the
battery life may be decreased.
JST-XH-2P
connector
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2.8.4 Replace the battery
You can change the battery in the NBSN95.The type of battery is not limited as long as the
output is between 3v to 3.6v. On the main board, there is a diode (D1) between the battery
and the main circuit. If you need to use a battery with less than 3.3v, please remove the D1
and shortcut the two pads of it so there won’t be voltage drop between battery and main
board.
The default battery pack of NBSN95 includes a ER26500 plus super capacitor. If user can’t
find this pack locally, they can find ER26500 or equivalence without the SPC1520 capacitor,
which will also work in most case. The SPC can enlarge the battery life for high frequency use
(update period below 5 minutes)
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3. Using the AT Commands
3.1 Access AT Commands
LDDS20 supports AT Command set in the stock firmware. You can use a USB to TTL adapter
to connect to LDDS20 for using AT command, as below.
Or if you have below board, use below connection:
In the PC, you need to set the serial baud rate to 9600 to access the serial console for
LDDS20. LDDS20 will output system info once power on as below:
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Below are the available commands, a more detailed AT Command manual can be found at
AT Command Manual:
http://www.dragino.com/downloads/index.php?dir=LoRa_End_Node/LDDS20/
AT+<CMD>? : Help on <CMD>
AT+<CMD> : Run <CMD>
AT+<CMD>=<value> : Set the value
AT+<CMD>=? : Get the value
General Commands
AT : Attention
AT? : Short Help
ATZ : MCU Reset
AT+TDC : Application Data Transmission Interval
Keys, IDs and EUIs management
AT+APPEUI : Application EUI
AT+APPKEY : Application Key
AT+APPSKEY : Application Session Key
AT+DADDR : Device Address
AT+DEUI : Device EUI
AT+NWKID : Network ID (You can enter this command change only after
successful network connection)
AT+NWKSKEY : Network Session Key Joining and sending date on LoRa network
AT+CFM : Confirm Mode
AT+CFS : Confirm Status
AT+JOIN : Join LoRa? Network
AT+NJM : LoRa? Network Join Mode
AT+NJS : LoRa? Network Join Status
AT+RECV : Print Last Received Data in Raw Format
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AT+RECVB : Print Last Received Data in Binary Format
AT+SEND : Send Text Data
AT+SENB : Send Hexadecimal Data
LoRa Network Management
AT+ADR : Adaptive Rate
AT+CLASS : LoRa Class(Currently only support class A
AT+DCS : Duty Cycle Setting
AT+DR : Data Rate (Can Only be Modified after ADR=0)
AT+FCD : Frame Counter Downlink
AT+FCU : Frame Counter Uplink
AT+JN1DL : Join Accept Delay1
AT+JN2DL : Join Accept Delay2
AT+PNM : Public Network Mode
AT+RX1DL : Receive Delay1
AT+RX2DL : Receive Delay2
AT+RX2DR : Rx2 Window Data Rate
AT+RX2FQ : Rx2 Window Frequency
AT+TXP : Transmit Power
Information
AT+RSSI : RSSI of the Last Received Packet
AT+SNR : SNR of the Last Received Packet
AT+VER : Image Version and Frequency Band
AT+FDR : Factory Data Reset
AT+PORT : Application Port
AT+CHS : Get or Set Frequency (Unit: Hz) for Single Channel Mode
AT+CHE : Get or Set eight channels mode, Only for US915, AU915, CN470
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4. FAQ
4.1 What is the frequency plan for LDDS20?
LDDS20 use the same frequency as other Dragino products. User can see the detail from this
link:
http://wiki.dragino.com/index.php?title=End_Device_Frequency_Band#Introduction
4.2 How to change the LoRa Frequency Bands/Region?
You can follow the instructions for how to upgrade image.
When downloading the images, choose the required image file for download.
5. Trouble Shooting
5.1 Why I can’t join TTN in US915 / AU915 bands?
It is due to channel mapping. Please see below link:
http://wiki.dragino.com/index.php?title=LoRaWAN_Communication_Debug#Notice_of_US9
15.2FCN470.2FAU915_Frequency_band
5.2 AT Command input doesn’t work
In the case if user can see the console output but can’t type input to the device. Please check
if you already include the ENTER while sending out the command. Some serial tool doesn’t
send ENTER while press the send key, user need to add ENTER in their string.
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6. Order Info
Part Number: LDDS20-XX
XX: The default frequency band
● AS923: LoRaWAN AS923 band
● AU915: LoRaWAN AU915 band
● EU433: LoRaWAN EU433 band
● EU868: LoRaWAN EU868 band
● KR920: LoRaWAN KR920 band
● US915: LoRaWAN US915 band
● IN865: LoRaWAN IN865 band
● CN470: LoRaWAN CN470 band
7. Packing Info
Package Includes:
➢ LDDS20 LoRaWAN Liquid Level Sensor x 1
Note:
Ultrasonic coupling paste and Eproxy AB glue are subjected in most shipping way. So
the default package doesn’t include it and user needs to purchase locally.
Dimension and weight:
➢ Device Size: cm
➢ Device Weight: g
➢ Package Size / pcs : cm
➢ Weight / pcs : g
8. Support
● Support is provided Monday to Friday, from 09:00 to 18:00 GMT+8. Due to different
timezones we cannot offer live support. However, your questions will be answered as
soon as possible in the before-mentioned schedule.
● Provide as much information as possible regarding your enquiry (product models,
accurately describe your problem and steps to replicate it etc) and send a mail to
support@dragino.com
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