Radar level sensor is the perfect choice for non-contact liquid level measurement. Suitable for sewage level measurement; low volatile acid and alkali level measurement; slurry level measurement.

SIRD-801 Radar Level Sensor-Suitable for Liquid, Slightly Corrosive Liquid

Radar level sensor antenna emits and narrow microwave pulse. This pulse propagates in space at the speed of light. When it encounters the surface of the measured medium, part of its energy is reflected back and received by the same antenna. The time interval between the transmitted pulse and the received pulse is proportional to the distance from the antenna to the surface of the measured medium. The 6GHz intelligent series radar level gauge is suitable for non-contact continuous measurement of the level of liquid, slurry, granular material and block material. Applicable In the occasions where temperature and pressure change greatly, inert gas and volatilization exist.

Sino-Inst offers a variety of Radar Level Sensors for industrial level measurement. If you have any questions, please contact our sales engineers.

Features of SIRD-801 Radar Level Sensor

  • The hardware system uses advanced microprocessors and embedded system processing software. The signal algorithm processing integrates advanced Echo-capture signal processing technology. This makes the product applicable to various complex industrial plant conditions.
  • The “empty tank pretreatment” technology enables the instrument to correctly identify effective echoes and obtain correct measurement results even in the presence of multiple false echo interference.
  • Not affected by various complicated working conditions. Such as strong surface fluctuations, foam, moisture and dust interference.

Specifications of SIRD-801 Radar Level Sensor

Applicable medium:liquid, slightly corrosive liquid
Application:Sewage level measurement;
Low volatile acid-base level measurement;
Slurry level measurement
Explosion-proof certification:Exia IIC T6 Ga/ Exd IIC T6 Gb
Measuring range:20m
Antenna:Rod antenna (PP/PTFE)
Frequency:6 GHz
Process temperature:(-40~130)℃
Measurement accuracy:±10mm
Process pressure:(-0.1~0.3)MPa
Signal output:(4~20)mA/HART
On-site display:four LCD programmable
Power supply:two-wire system (DC24V)
four-wire system (DC24V/AC220V)
Repeatability:± 1mm
Housing:aluminum single cavity/aluminum double cavity/plastic/stainless steel single cavity
Process connection:flange (optional)/thread

Radar Level Sensor’s Applications

  • Power plants: coal piles, raw coal bins, fuel bins, reservoirs, waste gas purification tanks, bin pumps, ash storage, etc.
  • Oilfield: crude oil or product oil storage tanks, three-phase separators, sedimentation tanks, sewage tanks (pools), drilling mud tanks, etc.
  • Petrochemical: distillation tower, concentration tank, liquefied gas tank, ammonia tank, steam drum, oil refinery tank, asphalt tank, etc.
  • Chemical industry: distillation tower, raw material and intermediate silo, reaction tank, ammonia tank, toxic liquid tank, solid silo, separator, etc.
  • Metallurgy: ore silo, ore crusher, raw material silo, auxiliary silo, blast furnace, alumina powder silo, electrolytic cell buffer tank, etc.
  • Cement: stone silos, raw meal silos, cement silos, coal powder silos, slag storage silos, etc.
  • Water and water treatment: reservoirs, sewage tanks, water treatment tanks, sedimentation tanks, digestion towers, etc.
  • Papermaking: raw material warehouse, storage tower, drying drum, etc.
  • Others: food, pharmaceuticals, environmental protection, shipbuilding, etc.

Extended reading: Radar Level Meter for Corrosive Liquids

Radar Level Sensor Working Principle

A low-frequency radar level meter is a 6GHz radar level measurement product. It uses an advanced microprocessor. The low-frequency radar has a long emission wavelength, and when encountering obstacles, it can cause diffraction to bypass the obstacles. Then, through optimized echo processing technology, false echo processing technology, and software digital processing technology, the true level is calculated.

The antenna types and process connections are diverse, which can be applied to various working conditions and application schemes. There are more unique application schemes for temperature, pressure and small dielectric constant. At the same time, it integrates HART communication technology and a modular digital display module. When the product is in application, the debugging scheme is diverse and the debugging is simple.

Antenna system to launch and microwave receiving energy is very low, very short pulse. Radar waves travel with the speed of light.  The running time can be through the electronic components are converted into a signal. Measurement of this special time extension method can realize stable, accurate in a very short period of time.

Even if the condition is very complex, the presence of false echo, with the latest micro-processing technology and debugging software also can analyze the level echo accurately.

Radar Level Sensor Working Principle

Microwave antenna to receive the reflected pulse and transmitted to the electronic circuit.

A microprocessor to signal to process, to identify the micropulse generated on the material surface echo.

Echo recognition is completed by the pulse system, the accuracy can reach millimeter level.

From the material surface distance between D and T pulse is proportional to the time travel:


Where C is the speed of light

Because of the air tank is a known distance E, L:


By setting the empty tank height E (= zero), the full height of F (= full scale), and some application parameters.

Application parameters automatically make the instrument measure the environment. 4 – 20mA with the corresponding output.

Extended reading: Radar Liquid Level Sensor|Corrosive, steam, volatile liquids

Radar Level Sensor Advantages and Disadvantages

Let’s analyze its advantages first:  

  1. The radar level gauge adopts an integrated design. It is mainly composed of electronic components and antennas. No moving parts. There is no mechanical wear. There are very few failures in use and long service life.  
  2. The electromagnetic wave emitted by the radar level gauge can pass through the vacuum without a transmission medium. It is not affected by the atmosphere, steam, and volatilized fog in the tank.  
  3. The radar level gauge can be used for almost all liquid level measurement.  
  4. Adopt non-contact measurement. It is not affected by the density and concentration of the liquid in the tank.  
  5. Large measuring range. The maximum measuring range can reach 0~35m. It can be used for high temperature and high pressure liquid level measurement.  
  6. Key components such as antennas are made of high-quality materials. It has strong corrosion resistance and can adapt to very corrosive environments.  
  7. Rich functions, with false wave learning function. Enter the actual liquid level of the liquid surface, and the software can automatically identify the false echoes from the liquid surface to the antenna and eliminate the interference of these waves.  
  8. The parameter setting is convenient, and it can be set with the simple operation keys on the level gauge. It can also be modified with a handheld communicator.

The main disadvantages are as follows:

  1. Determine the height of the measured storage medium tank during calibration. And after empty calibration, the output of zero and full scale is set to 4mA for empty tank zero point and 20mA for full tank (maximum range).
  2. Some volatile organic matter in the measuring medium will crystallize on the horn or antenna of the radar level gauge. They need to be inspected and cleaned regularly.  
  3. Interference wave influence. In daily maintenance, you can use a PC (with VEGA Visual Operating software) to remotely observe the reflected wave curve. For possible interference waves, the level gauge can be used to identify false waves. Remove the influence of these interference reflection waves to ensure accurate measurement.

Extended reading: Drop Antenna Radar Tank Level Sensor

According to the measurement method of radar level transmitter, there are two common ones:

  • Pulse type. The transmitted radar wave pulse of the antenna period;
  • FM continuous wave type. The antenna emits a radar wave signal that changes continuously around a fixed frequency.

Pulse radar level transmitter can also be called pulse radar level transmitter. It adopts pulse working mode. It also cooperates with a variety of output circuit interfaces and acquisition systems.

Pulse radar level transmitter has the advantages of wide application range, strong reliability, convenient maintenance, simple operation, and can measure almost all media.

Pulse radar level transmitters are generally used in spherical tanks, cylindrical tanks, cylindrical conical tanks and other containers. It can measure various liquids such as tap water, hydrochloric acid, industrial wastewater, cement slurry, etc. The above is the introduction of Pulse radar level transmitter and its advantages.


  • Long life span, stable and reliable operation, easy installation, almost no maintenance
  • None influence of measured medium in physical and chemical state. Eg: medium electrical conductivity, dielectric constants, foam, pressure, temperature, evaporation, boiling, bubbling effect etc, .
  • Choose appropriate material can be used in a variety of bad media environment with densities ≥ 0.5G/CC ;
  • Interface measurement with two media of different density control;
  • Wide range of application. Pressures from vacuum to PN160 (special up to PN320), temperature -40~+150 ° c
  • Design, explosion-proof, suitable for explosive environments;
  • Controller can be used to control the upper and lower liquid level.


  • Low accuracy.
  • The installation position is limited by the shape of the container.
  • Most float level gauges are not suitable for corrosive or hazardous liquid media.

More Featured Float Level Sensors:

SI-U01 Float Level Sensor
SI-U02 Multi-Point Liquid Level Float Switch
SI-U03 Float Switch Water Level Controller
SI-U04 Magnetic Float Level Sensor-Reed Switch
SI-U05 Cable Float Level Sensor & Swtich

Featured Radar Water Level Sensors

High frequency and low frequency Radar Level Sensor

The microwave frequency used by the microwave level meter has three frequency bands: C band (5.8~6.3GHz), X band (9~10.5GHz), K band (24~26GHz).

The microwave in level measurement is generally directional emission. The beam angle is usually used to quantitatively express the directivity of microwave transmission and reception. The beam angle is related to the antenna type and also to the microwave frequency (wavelength) used.

For the antenna of the same size, a level gauge with a wavelength of 1.2cm and a frequency of 26 GHZ has 6 times higher gain than a level gauge with a wavelength of 3cm and a frequency of 10 GHZ. The antenna gain is a parameter indicating the concentration of radiation from a directional antenna.

The receiving signal diagrams of different frequencies (26/10/6 GHZ), the same antenna, dielectric constant and distance increase are as follows:

High frequency and low frequency Radar Level Sensor

Extended reading: Radar Non Contact Water Level Sensor

The total beam width of the radar level gauge is inversely proportional to the frequency of the device. Therefore, for an antenna of the same diameter, if the frequency of the radar level gauge is increased, the beam width will be lower than that of a lower frequency device. The narrow beam minimizes the influence of the nozzle, tank wall and interference.

At the same time, the measurement range of the radar level gauge is also affected by factors such as frequency, antenna size, dielectric constant of the liquid, and process conditions.

The application difference between high frequency and low frequency of radar level sensor.

Low-frequency radar level gauges are preferred when measuring steam, foam, and condensate. In most other applications, high-frequency radar level gauges are preferred for ease of installation.

  1. The lower frequency reduces the sensitivity to steam, foam and antenna contamination. The low-frequency radar has a wider wave speed angle. It can better deal with the problems of steam, dust, condensation, pollution and turbulent surfaces.
  2. The higher frequency minimizes the impact on the nozzle, tank wall and interference.

Of course, in addition to radar level sensors, ultrasonic level sensors are also a good choice for non-contact level measurement.


Most liquid level sensors can measure the water level.
But from the comprehensive analysis of cost and use, the Hydrostatic Level sensor is the choice of most customers.
More about Hydrostatic level measurement.

In actual application, there are two methods for radar level sensors, namely, frequency modulated continuous wave type and pulse wave type. The liquid level sensor using FM continuous wave technology has high power consumption, must adopt a four-wire system, and the electronic circuit is complicated.

The liquid level sensor using radar pulse wave technology has low power consumption and can be powered by two-wire 24VDC, which is easy to achieve intrinsic safety and has a wider application range.

Ultrasonic sensors use sound waves, and radar uses electromagnetic waves. This is the biggest difference.

Moreover, the penetrating ability and directivity of ultrasonic waves are much stronger than electromagnetic waves, which is why ultrasonic detection is more popular now.
The difference between the main applications:
   1. Ultrasonic accuracy is not as good as radar.
   2. The relative price of radar is relatively high.
  3. When using radar, consider the dielectric constant of the medium.
   4. Ultrasound cannot be applied to working conditions such as vacuum, high steam content or foam on the liquid surface.
   5. The radar measurement range is much larger than that of ultrasonic.
   6. The radar has a horn type, a rod type, and a cable type. Compared with ultrasonic, it can be applied to more complicated conditions.

Types of Level Transmitters:
Level measurement transmitters are of seven types. Each type of transmitter works in a different way, and makes it useful for different types of processes.

Capacitance Level Transmitters
Hydrostatic Level Transmitters
Magnetic Level Transmitters
Radar Fill Level Transmitters
MUltrasonic Level Transmitter
Guided Microwave Level Transmitters
Hydrostatic level transmitters
Extended reading: FMCW Radar Level Transmitter 120GHz

The radar level gauge adopts the transmitting-reflecting-receiving working mode. The antenna of the radar level gauge emits electromagnetic waves. These waves are reflected by the surface of the measured object and then received by the antenna.

The time from emission to reception of the electromagnetic wave is proportional to the distance to the liquid surface. The radar level gauge records the pulse wave experience Time.

And the transmission speed of the electromagnetic wave is constant. The distance from the liquid surface to the radar antenna can be calculated to know the liquid level of the liquid surface.

The radar level sensor can emit radar wave signals through its own antenna. It runs in space at the speed of light. When it hits the surface of the material, it is reflected back to the radar antenna. The microprocessor converts the distance signal into a liquid level signal to achieve liquid level measurement.

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Sino-Inst offers over 10 Radar Level Sensors for level measurement. At best price. About 50% of these are Radar level meters, 40% is the tank level sensor.

A wide variety of Radar Level Sensors options are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of Radar Level measurement instrumentation, located in China.