What Is a Water Level Transducer?

Water level transducers are also called Water Level Sensors, or water level transmitters. Water level transducers are used to monitor water usage and quality. The water level signal is output through 4-20mA and other signals, which is convenient for people to monitor the water level.

There are many types of water level transducers. Common ones are input type, ultrasonic, radar and so on.

Sino-Inst offer a wide range of solutions with various pressure ranges, cable lengths and output options.

For remote monitoring and recording of water level data in groundwater pumping and sludge testing, stormwater flood analysis and runoff, and surface water irrigation canals, streams and river measurements.

Water Level Transducers

Featured water level transmitters for Sale

level transducer types

In various industrial production processes, many auxiliary safety products are used. Among them, level transducer, as one of the most common auxiliary products, has many names. The following are 20 common level transducers:

  • Magnetic flap liquid level transducer
  • Float level transducer
  • Steel belt level transducer
  • Radar level transmitter
  • Magnetostrictive liquid level transducer
  • RF Admittance Level Transducer
  • Tuning Fork Level Meter
  • Glass plate/glass tube level transducer
  • Hydrostatic level transmitter
  • pressure level transmitter
  • Capacitive Level Transducer
  • Intelligent electric displacer liquid level transducer
  • Buoy Level Transducer
  • Displacer Level Transmitter
  • Electric contact level transducer
  • Magnetic two-color electronic liquid level transducer
  • External level transmitter
  • Hydrostatic Level Transducer
  • Ultrasonic Level Transducer
  • Differential pressure level transmitter (double flange level transmitter)

Extended Reading: What is level transmitter working principle?

types of water level sensors

We can divide Water Level Sensors into two categories by measuring whether they are in contact with the water level.

One type is contact type. Including single flange static pressure/double flange differential pressure level transmitter, float type level transmitter, magnetic level transmitter, input type level transmitter, electric internal float level transmitter Sensors, electric float level transmitters, capacitive level transmitters, magnetostrictive level transmitters, service level transmitters, etc.

The second category is non-contact. Divided into the ultrasonic level transmitter, radar level transmitter, and so on.

Extended Reading: Chilled Water Flow Meter

submersible water level sensor

Submersible level transmitter is a kind of Hydrostatic water pressure level transmitter. It is widely used for its simple installation and reasonable price. Providing quick, accurate and reliable level measurement.

Cable 0m ~ 300m, minimum range 0.5m.

Submersible Water Level Sensor Specifications

Measurement form and range0~1~200mH2O
Overload allowed3 times full scale pressure
Operating temperature-20~80℃
Temperature compensation-10~70℃
Storage temperature-40~80℃
Accuracy (including nonlinearity, repeatability, hysteresis)0.2%FS(Typical) 0.5%FS(Maximum)
Stability error0.2%FS(Typical), 0.5%FS(Maximum)
Temperature drift coefficient0.01%FS (typical, range not less than 5mH2O)
0.03%FS (typical, less than 5mH2O)
Output signal(4~20)mA, (0~10/20)mA
(0~5)V, (1~5)V, )0~10)V
Power supply15~36 VDC (calibration voltage 24VDC)
Load (Ω)Current output type<(U-15V)/0.02A, current output type>5K
Shell materialStainless steel
O-ringFluorine rubber
Diaphragm316L stainless steel
CableSpecial waterproof and breathable cable
Protection classIP68 (pressure sensor part), IP65 (junction box transmitter part)

Learn More About Submersible Level Transducer

Radar sensor for water level is a level detection instrument using microwave technology. It is mainly suitable for detecting the water level of natural waters such as rivers and lakes. It can also be used for water level detection of large reservoirs, reservoirs, sewage canals and other open-air channels.

As a detection terminal, this product can effectively assist in monitoring the state of water level changes and provide accurate water level information for monitoring units.

radar sensor for water level
Extended Reading: LORA water meter

The product adopts the pulse radar detection method, which can work stably around the clock. The measurement results are accurate and reliable.

The non-contact detection method makes its application range more extensive. It can even be used in complex water environments with organic pollutants or sediments.

radar water level sensor

Application: Rivers, Lakes, Shoal
Measuring Range: 70 meters
Process Connection: Thread G1½ A″ /Frame /Flange
Temperature: -40℃ ~ 100℃
Process Pressure: Normal pressure
Precision: ± 3mm; ± 10mm
Frequency Range: 26GHz
Protection Grade: IP67 / IP65
Power Supply: (6 – 24V) DC  / Four-wire
24V DC / Two wire
The Signal output: RS485 / Modbus ( 6~24V DC)
4~20mA / Hart Two wire ( 24V DC)
The Scene Display: Optional
Outer Covering: Aluminum / Plastic / Single chamber

Extended reading: Amazing Solutions for Continuous Liquid Level Measurement

The principle of liquid level measurement of pressure sensor

In physics, the pressure P of a liquid is determined by the relationship: p=ρgh.

For the same liquid, the liquid density ρ is constant. Therefore, the pressure P of the liquid is linearly proportional to the height h of the liquid surface (the height from the liquid surface). It is not difficult to find that the pressure of the liquid at different heights of the liquid level is also different.

When the pressure sensor is used to measure the liquid level, the pressure sensor is installed at the bottom of the tank. When the liquid level in the tank changes, the height h from the tank bottom to the liquid level is also changing at the same time. The pressure will naturally change accordingly. Thus, the purpose of continuous measurement is achieved.​​

One of the advantages of using pressure sensors for liquid level measurement is non-contact. Compared with mechanical and static methods, when measuring, it does not require many parts to be in contact with the liquid, and the installation is relatively convenient.

In addition, in terms of measurement principle, compared with similar non-contact measurement methods such as laser and ultrasonic, the relationship between pressure sensor measurement principle is simpler and linear, and it is more intuitive in data processing, analysis and processing.

Extended reading: Float Switch Water Level Controller

How does a water level transducer work?

Water level transducer is an instrument that can convert the water level parameter of the measured point into the corresponding electric quantity signal in real time.

The working principle of the Water level transducer is that when it is put into a certain depth in the liquid to be measured. The pressure on the sensor’s front surface is converted into the liquid level height.

The calculation formula is Ρ=ρ.g.H+Po.

In the formula P is the pressure on the liquid surface of the sensor;
ρ is the density of the liquid to be measured;
g is the local acceleration of gravity;
Po is the atmospheric pressure on the liquid surface;
And H is the depth at which the sensor drops into the liquid.

Extended reading: How to convert a 4-20mA to 0-10V /1-5V signal?

industrial water level sensor advantages and disadvantages

At present, the Submersible Water Level Sensor is the most used one.

Submersible Water level transducers generally use the piezoresistive effect of diffused silicon or ceramic sensing elements. Convert static pressure into electrical signal. Temperature compensated and linearity corrected. Converted to 4-20mADC standard current signal output.

The Submersible Water level transducer is directly put into the liquid, and the transmitter part can be fixed by flange or bracket, which is extremely convenient to install and use.
The benefits of water level sensors

  • Good stability and high precision;
  • The Submersible Water Level Sensor is put directly into the measured medium. It is very convenient to install and use;
  • Input type, straight rod type, flange type, threaded type, inductive type, screw-in type, floating ball structure design. Anti-blocking design is available.
  • Simple installation, convenient use and strong interchangeability. High-quality level gauges have high sensitivity.
  • The response speed is fast, and it accurately reflects the subtle changes of flowing or static liquid level.
  • High measurement accuracy.
  • Solid-state structure, no moving parts, high reliability.
  • Long service life High-precision measurements are possible from water and oil to more viscous pastes.
  • A wide range of temperature compensation is not affected by the foaming, deposition, and electrical properties of the measured medium.
  • The Submersible Water Level Sensor has power reverse polarity protection and overload current limiting protection.

The disadvantages of Submersible Water Level Sensor are:

  • The measurement signal needs to be converted;
  • Cannot measure the temperature of high temperature medium over 125℃;
  • The density of the measuring medium must be uniform.

These points also limit its scope of use. But for water level measurement, Submersible Water Level Sensor is the perfect choice.

Extended Reading: 3 inch (3″) Water Meter

water level sensor applications

Uses of water level sensors include the following applications:

  • Water level measurement in pools and tanks
  • River and lake water level measurement
  • Marine level measurement
  • Level measurement of acid and alkali liquids
  • Oil level measurement of oil trucks and mailboxes
  • Swimming pool water level control
  • Tsunami Warning and Sea Level Monitoring
  • Cooling tower water level control
  • Sewage pump level control
  • Liquid level remote monitoring

Extended reading: Sludge Blanket Level Detector Appliactions

The river water level monitoring system is an important means to grasp the changes of river water conditions in real time, scientifically warn flood disasters, improve flood control command ability, and reduce the losses of rain and flood disasters.

System functions:

  • Real-time monitoring of river water level, expandable monitoring of rainfall, water quality and flow velocity.
  • Support remote photography or video real-time monitoring (video communication).
  • When the water level exceeds the limit, the sensor fails, and the battery voltage of the monitoring terminal is low, it will alarm immediately.
  • Automatically generate water level process curves and data statistical reports.
  • It can be linked with the drainage pump station. Automatically control the start and stop of the drainage pump group according to the water level of the river.
  • Support through OPC, database and other forms. Docking with other comprehensive monitoring application platforms.

The river water level monitoring system is compatible with various water level gauges such as ultrasonic, radar, float, laser, bubble, and input type.

Extended Reading: Low Cost Float Level Sensor for Tank Liquid Volume Monitoring

The reservoir/lake water and rain monitoring system is suitable for the water management department to remotely monitor the real-time data and on-site images such as the water level and rainfall of the reservoir/lake. In order to keep abreast of the changes in the water storage capacity of the reservoir/lake, to ensure moderate water storage and safe flood season.

  • Real-time monitoring of water level and rainfall of reservoirs/lakes, and timely grasp of water storage conditions
  • During optical fiber/5G/4G/3G communication, it supports real-time video surveillance. During 2G communication, it supports remote photography.
  • When the water level, rainfall exceeds the limit or the on-site equipment fails, it will automatically alarm and send an alarm text message to the mobile phone of the watchman. Automatically generate water level, rainfall time, day, month, year statistical reports and analysis curves.
  • Provide system interface. Support integration into the upper-level flood control and drought relief command system

Extended reading: Ultrasonic Water Meter Working Principle

digital water level recorder

Universal Input-Paperless Recorder R7100

Paperless Recorder is an intelligent Digital chart recorder. Data can be remotely recorded, analyzed, stored, and signal output. LCD color screen, maximum 16 channels.

R7100 series color paperless recorder supports 1-16 channels of universal input. R7100 has a powerful display function, real-time curve display, historical curve recall, bar graph display, alarm list display, power-down list display.

Configurable and optional inputs: standard voltage, standard current, thermocouple, thermal resistance, frequency, switch value, pulse, etc. It can be equipped with 6 relay alarm outputs, 6 feed outputs, 4 transmitter outputs, and RS232/485 communication interface is optional. Bluetooth function, GPRS function Ethernet interface, micro printer interface and USB interface.

Sino-Inst offers a variety of digital water level recorder instruments for industrial control. If you have any questions, please contact our sales engineers.


Level transducers are generally used where liquid level measurements need to be measured, and are suitable for liquid level and interface measurement of liquid media in containers. Level transducer is suitable for liquid level measurement of various media in petroleum, chemical, metallurgy, pharmaceutical and other industries.

Most of the measurement objects of Level transducers are liquid media. Because the objects to be measured are different, the measurement methods are also different. Therefore, Level transducers can be divided into many types. For example, there are ultrasonic liquid level sensors, input liquid level sensors, Magnetic flap liquid level sensor, etc. They are all a type of Level transducer.

There are many types of Water Level Transducers. Each Water Level Transducer has its own advantages.
Which is the best sensor for water level? There is no fixed answer.
You need to choose the best Water Level Transducer based on your measurement parameters.

Extended reading: Non contact level measurement

Level transducers are also called level transmitters. The Level sensor senses the change in liquid level and transmits the liquid level signal to the circuit board. After the conversion of the circuit board, the output is 4-20mA or other signals. This is the level transducer.

Water level measurement must first confirm the purpose of the measurement. Whether to monitor the height of the water level in real time or to alarm at a certain position to determine whether to choose a switch or continuous sensor.

Then select the appropriate Water Level Transducers.

If you need non-contact measurements. Then you can choose to use ultrasonic level meter. Ultrasonic technology is not only used to measure level, but also can be used to measure depth.

In liquid, the pressure generated at a certain depth is generated by the weight of the medium itself above the measurement point. It is proportional to the density of the medium and the local acceleration of gravity.

The formula P = ρgh reflects the proportional relationship between them.

Where P = pressure, ρ = medium density, g = gravity acceleration, h = depth of measurement point.

Therefore, the physical quantity measured by the input liquid level gauge is actually pressure. It can be understood by the calibration unit mH2O of the input level gauge. The actual liquid level must be obtained by conversion after knowing the two parameters of density and gravity acceleration. In the industrial field, such conversion is usually performed by a secondary instrument or PLC.

IP rating is short for Ingress Protection. The IP rating is the degree of protection for the enclosure of electrical equipment against the intrusion of foreign objects. The source is the standard IEC 60529 of the International Electrotechnical Commission. This standard was also adopted as an American National Standard in 2004.

If a submersible sensor is required. Then it needs to reach IP68.
Our Submersible Water Level Sensor can meet IP68.

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Sino-Inst offers over 10 Water Level Transducers About 50% of these are submersible liquid level meters, 40% is the others types.

A wide variety of Water Level Transducers for Liquid Level Measurement options are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of Water Level Transducers for Liquid Level Measurement instrumentation, located in China.

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