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Smart Cities Solution Supplier CNDingtek

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  1.   Ultrasonic Liquid Level Sensor DF520
  2.   Ultrasonic Liquid Level Sensor DF520
  3.   Ultrasonic Liquid Level Sensor DF520
  4.   Ultrasonic Liquid Level Sensor DF520
  5.   Ultrasonic Liquid Level Sensor DF520
  6.   Ultrasonic Liquid Level Sensor DF520

Ultrasonic Liquid Level Sensor DF520

1 OverviewThe DF520 is one kind of ultrasonic liquid level sensor, which can detect the liquid level by outside bottom installation without drilling holes. The tank thickness can b

  1. Detailed information

1 Overview

The DF520 is one kind of ultrasonic liquid level sensor, which can detect the liquid level by outside bottom installation without drilling holes.

 The tank thickness can be up to 10mm. (For special thickness, please contact with CNDingtek for confirmation.) The resolution is 1mm or 0.1%FS (the bigger value). The measurement ranges from 0-10 meters. It can be used for kinds of tanks, including iron, aluminium alloy, plastic and etc. It is applicable for automotive, oil station, chemical storage, LPG tank, and other industrial tanks to realize realtime monitoring of storage, online inventory management, statistics and estimation of production.

With built-in 4G, data can be passed to the cloud server via 4G.Finally user can monitor the realtime level remotely. The supported frequency bands are f B1,B2,B3,B4,B5,B6,B8,B20,B28 and so on.  

There are two versions of the power supply, one with an internal battery and the other with an external power supply.The battery version can work for the projects where power supply is not so easy.

It is opened for customized design (OEM/ODM) on hardware or software.


2 Specification





Transducer ø30, Controller box 80*78*30mm






Detection Range

30~ 10000mm

Blind area



3mm or 0.3%FS, the bigger one


1mm or 0.1%FS, the bigger one

Driving Frequency




STM32, 32bit ARM® core controller


4G Module



-137dbm@292bps (RX),5~20dbm(Tx)


B1,B2,B3,B4,B5,B6,B8,B20,B28 and so on


Option I: external power supply

6-13.8V DC

Option II: inner battery

ER26500 8000mAh 3.6VDC, non-recharged.

Every day 4 times upload, battery can work for more than 2 years.


Operating Temperature

-20 ~ +70

Storage Temperature

-40 ~ +85

Protection Level




Diesel,gasoline, water, LPG, Ethanol, and other liquids


Bottom glue fasten

Transducer stick to tank bottom by glue.


3 System Diagram

wireless sensor| ultrasonic sensor | IOT sensor

4 Wire Definition for External power supply version


Function for external power supply version







Power GND, RS232 GND



RS232 Tx for led display or pc com port debug



RS232 Rx for led display or pc com port debug


Notes: If there is labels on sensor for pin definition, please act as the labels.

             For inner battery version, no need to connect with cable.

5 Network Diagram

wireless sensor| ultrasonic sensor | IOT sensor

The DF520 intelligent detector transmits data to the 4G base station via the 4G network, and then the 4G base station transmits the data to the Internet of Things cloud network via the Internet, and finally sends the data to the application server and the user terminal via the Internet. As a result, users can monitor the level of the status via the web.

6 Package List






Controller Box


 Drive ultrasonic transducer and upload signal


Ultrasonic Transducer


  Transducer attached to bottom of container


Band (tie)


Fasten transducer and cable


Abrasive Paper


Clean the coating of installation point

5 *

Couplant (vaseline)


Put between the transducer and container While finding the installation point




Put between transducer and container for real installation after installation point found. Applicable for aluminium alloy, steel, plastic tank. Recommend one component RTV Silicon Adhesive 703 or  Loctite 380.


wireless sensor| ultrasonic sensor | IOT sensor

*: The couplant and glue is forbidden to delivery for airplane shipping or express shipping. So we do not offer them in the standard package.  

Please purchase at local market. The couplant (vaseline) is easy to find at medical store.

It is applicable if you can find one of the RTV silicon adhesive 703, or loctite 380.  (if you can not find the recommend glue, you can choose other glues, and their freezing time is less than 10 minutes )

7 Installation 


7.1 Preparation & Cleaning 

Before installation, please make sure the tank is horizontal so that the sensor can be  perpendicular to the liquid level. Otherwise, the sensor maybe can not get correct value or even no value output.

For good result of installation, it is recommended to keep the liquid more than 10cm height. Because the sensor blind area is 3cm.

wireless sensor| ultrasonic sensor | IOT sensor

Select one flat area on bottom of the container, and clean the dirt on the flat area to make it smooth. If paint cover on the steel tank, please use the abrasive paper to remove the paint cover. After cleaning, there is no any part between the transducer and the bottom shell of the container.

7.2 Finding Installation Position

Connect the power supply with the controller box as well as the transducer.  Power on it. At the beginning, you can check the data on network server or application server.

Put couplant on the surface of transducer. Then put it on the cleaning area where you want to install the sensor.

wireless sensor| ultrasonic sensor | IOT sensor

Monitor he data value on network server or application server, and move the sensor slowly. Please check the level value with the real level height. If it is matched, then this point is the good position for installation.

If you can not find the position with value matched with the real level value, please check the couplant to make sure air is prevent from the sensor and tank bottom. The failed reason maybe the material of the container, the thickness of the container, the frame in the container, the dust in the bottom of the container.

Please remove the couplant on container and transducer surface before move to next step.

7.3 Installation with glue

Glue is applicable for steel tank as well as aluminium alloy or plastic tank.

Put glue on the transducer surface, stick them on the position you remarked at previous step. Monitor the status value on server, make sure it is the correct level of liquid, fasten the transducer with the container. Keep it while the glue solid the transducer.

Install the transducer protection part and fasten the transducer with the tie. Make sure to use tie to fasten the transducer. If only glue, maybe it will fail after some time because of the weight and vibration.

7.4 Routing wire

Use insulative tape to protect the connecting part of the transducer and the extended cable as well as the signal, power connection part.

Fasten the cable around the device or vehicle, make sure to avoid the heat part.


8 Protocol 

The communication protocol is confidential is only open for customer who has purchase the device and sign the NDA(non-disclosure agreement) file with CNDingtek.

 Please contact our sales team service@dingtek.com if you want to integrate the protocol with your own system.

Notes: The protocol maybe update without notification. Please contact with us for the latest protocol.


9 Package


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10 Video Link

https://youtu.be/ME3nFbgAs48  test of RS485 version DF520

https://youtu.be/XSQ28iMmMIo  installation of transducer with RTV one component silicon


11 FAQ

Question: After some time, the sensor is not data or data greatly change at short time, what is the reason?

If the installation is not so fix, or the glue is not so strong, it will defect after some time. If air come into the gap between the transducer and the tank shell, it will result in fail. As a result, the sensor will do not output data or output data suddenly change greatly.

Question:  Can we use this sensor for more than 10 meters tank?

No, this sensor is designed for 0-10 meters range. If more than this range, please contact with our service team to evaluate.

Question: Can you offer the OEM version for us? Without CNDingtek logo?

Yes, it is applicable for us. Please contact with our sales representative on this issue.

Question: Can this sensor work for plastic tank? Glass tank?

Yes, we tested with plastic tank, aluminium tank, iron tank, glass tank, it worked.

Question: Can we use glue other than the AB epoxy?

Yes, you can try. But make sure the glue is good performance for vibration.

Question:  Why can not read the correct level data?

  1. There is air between the probe and the bottom of container; please use the vaseline or glue ,then install gprobe.

  2. The thickness of the container bottom  is more than 1cm;

  3. Multi-layer material at the bottom of the container.



12 After Sales

E-mail: service@dingtek.com