Sanitary Level Sensor is a radar level measuring instrument. The preferred level sensor for level measurement requiring Hygienic requirements.

Features of SIRD-906 Radar Sanitary Level Sensor

1) Requirements for non-toxic and harmlessness of radar level gauge materials: different grades of stainless steel materials (304L, 316L, 410, 409, 329) are selected according to different conditions.

The selected polymer materials, various rubber elastomer materials, adhesives, lubricants, measuring conductive fluid materials, thermal insulation materials, outer plating materials, etc. must not contain toxic and harmful components, and must not have toxic and harmful components seep or infiltrate Wait.

2) The structure of the radar level gauge: the surface is smooth and clean (the surface polishing is preferably less than 0.8um), and there is no dead angle. It is not easy to accumulate residue, pollution and easy to wash.

3) Radar level meter certification: sanitary instruments usually need to obtain 3A sanitary certification. Or can obtain a third-party sanitation test report to meet GMP/FDA requirements.

Specifications of SIRD-906 Radar Sanitary Level Sensor

Application：	Hygienic liquid storage container, strong corrosive container
Measuring Range：	20 meters
Process Connection：	Flange
Process  Temperature：	-40～130℃(standard type) / -40～200℃(high temperature type)
Process Pressure：	-0.1～4.0MPa
Accuracy：	±3mm
Protection Grade：	IP67
Frequency Range：	26GHz
Supply：	Two-wire system (DC24V) / Four-wire system (DC24V/AC220V)
Signal Output：	Exia ⅡC T6 Ga / Exd IIC T6 Gb
Outer Covering：	Aluminum Single Chamber / Aluminum Dual Chamber / Plastic / Stainless Steel Single Chamber
Explosion-proof Grade：	4…20mA/HART (two-wire/four-wire) / RS485 Mod bus
Antenna Material	Stainless steel / PTFE

Ultrasonic vs Radar Level Sensor

There are three main differences between Ultrasonic and Radar Level Sensor:

Difference 1. The measurement range is different

Ultrasonic liquid level du measuring range: 0-50 meters;

The radar level gauge can measure all media with a dielectric constant> 1.2 in a vacuum, and the measurement range can reach 70 meters.

Difference 2: Different emission materials

The ultrasonic level gauge emits sound waves from the sensor (transducer), which is reflected by the liquid surface and then received by the same sensor or ultrasonic receiver;

Very short microwave pulses with very low energy emitted by the radar level gauge are transmitted and received through the antenna system, and the radar waves move at the speed of light.

Difference 3: Different measuring substances

Ultrasonic level gauges are widely used to measure the height of various liquids and solid materials. Water and sewage treatment. Pump house, collection well, biochemical reaction tank, sedimentation tank, etc. Electric power, mines: mortar pool, coal slurry pool, water treatment, etc.

The radar level gauge can measure liquid and solid media. For example: crude oil, slurry, raw coal, pulverized coal, volatile liquid, etc.

Extended reading: Sludge flow meter for sewage treatment return activated sludge system

Radar Water Level Sensor

Pulse radar level transmitters provide water level measurement based on directly measuring the running time of microwave pulses transmitted to and reflected from the surface of the river being measured. Using rs485 two-wire signal transmission, power supply and low power consumption are safe for outdoor use.

RS485 interface can be connected with 485 line, insert 4g sim card in dtu. 232 to usb to connect to the computer. Open the configuration tool and set the server address and port in the dtu configuration tool.

The server port monitors to receive the data, and it can be analyzed according to the sensor protocol. If the platform is developed to the modbus standard, the sensor also supports modbus. The whole analysis process will be simpler.

Realize remote monitoring and management of liquid level and water level outdoors. Both dtu and sensor industrial-grade outdoor design can be powered by solar energy. Therefore, radar water level gauges can be used in some of the most challenging water level applications.

Advantages:

• dtu rs485 bus access. Multi-device access, support rs232 interface;
• Strong compatibility. Can be connected to five-parameter water quality equipment. Multiple sensors use one gateway;
• Installed on the shore of the water area, on the measuring frame or “extension arm”. Adjust the mounting bracket according to the terrain;
• The installation is simple and the price is low. No need for expensive installation procedures;
• Low power consumption power supply enables the equipment to operate independently in the most remote areas;
• Non-contact measurement principle. Not damaged by silt accumulation or debris;
• Wireless transmission, avoid the trouble of pulling cables. Install and use, remotely unattended;
• High-level industrial requirements for the appearance of the iron shell. Application in hazardous areas and harsh environments;

Extended reading: Radar Level Meter for Corrosive Liquids

More Water Level Sensors

Sino-Inst offers a variety of water level sensors for a wide range of conditions. Our sensors are ideally suited for monitoring water levels in streams, dams and reservoirs. Our water level sensor products include:

• Submersible Pressure Transducers
• Radar Level Sensors
• Magnetostrictive Level Sensors
• Pressure Transducers
• Ultrasonic water level sensor

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

A wide variety of Radar level Sensors for level measurement 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.

Request a Quote

Horn Antenna Radar Tank Level Sensor is a common non-contact tank level meter. Suitable for high temperature sealed storage tank. Support customized high temperature 500-1000℃.

Features of SIRD-905 Horn Antenna Radar Tank Level Sensor

• Non-contact continuous liquid level measurement with larger range
• High-precision and precise transit time measurement brought by high-frequency pulse waves
• Sealed pressurized container will not affect performance
• Longer range than ultrasound
• If the corresponding cooling measures are adopted, the temperature of the measured medium can reach 1000°C.

Specifications of SIRD-905 Horn Antenna Radar Tank Level Sensor

Application：	Solid particles, powder
Measuring Range：	Liquid 35 meters / solid block 20 meters / solid powder 15 meters
Process Connection：	Thread, flange
Process  Temperature：	-40～130℃(standard type) / -40～250℃(high temperature type)/customized high temperature
Process Pressure：	-0.1～4.0 MPa (flat flange) -0.1～0.3 MPa (universal flange)
Accuracy：	±15mm
Protection Grade：	IP67
Frequency Range：	26GHz
Supply：	Two-wire system (DC24V) / Four-wire system (DC24V/AC220V)
Signal Output：	Exia ⅡC T6 Ga / Exd IIC T6 Gb
Outer Covering：	Aluminum Single Chamber / Aluminum Dual Chamber / Plastic / Stainless Steel Single Chamber
Explosion-proof Grade：	4…20mA/HART (two-wire/four-wire) / RS485 Mod bus
Antenna Material	Stainless steel 316L horn/PTFE vibrator, cone antenna

Radar Tank Level Sensor Applications

• Power plants: coal piles, raw coal silos, fuel silos, reservoirs, waste gas purification tanks, silo pumps, ash storage, fuel tanks, etc.;
• Oilfield: crude oil or product oil storage tanks, three-phase separators, settling tanks, sewage tanks and oil-water interfaces, drilling mud tanks, etc.;
• Chemical industry: crude oil distillation tower, raw material and intermediate silo, reaction tank, ammonia 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.;
• Papermaking: raw material warehouse, storage tower, drying drum, chemical material storage warehouse, etc.;
• Cement: storage warehouse for stone, raw meal, cement, coal powder, slag, etc.;
• Water treatment: water storage, sewage, sedimentation, deep well, drinking water and other pools;
• Others: quarry, food, pharmaceutical, environmental protection, shipbuilding and other industries;

Extended reading: Radar level sensor for solids – Dust solid level measurement

Radar Tank Level Sensor Installation Notes

(1) The horn of the horn-type intelligent radar level gauge must exceed the inner surface of the mounting hole by a certain interval (at least greater than 10mm).

(2) The axis of the antenna of the intelligent radar level gauge should be perpendicular to the reflective surface of the liquid level.

In addition, when performing routine maintenance on the intelligent radar level gauge, users can remotely observe the reflected wave curve with a PC (equipped with MAT software). For interference waves that may be newly generated later, the level gauge can be used to identify false waves. Remove the influence of these interference reflection waves to ensure correct measurement.

(3) Objects such as the stirring valve in the tank, the adhesion of the tank wall and the path. If it is within the signal range of the intelligent radar level gauge, it will produce interfering reflected waves and affect the level measurement. When installing, choose a suitable installation location to avoid interference from these factors.

Extended reading: Radar Level Meter for Corrosive Liquids

Radar Tank Level Sensor Installation Guide:

Radar Level Sensor Working Principle

Radar level transmitter antenna microwave pulse is narrow, the downward transmission antenna.

Microwave exposure to the medium surface is reflected back again by the antenna system receives, sends the signal to the electronic circuit automatically converted into level signals.

Because the microwave propagation speed, electromagnetic wave to reach the target and the reflected back to the receiver this time is almost instantaneous.

Datum measurement:  Screw thread bottom or the sealing surface of the flange.

Note: Make sure the radar level meter the highest level cannot enter the measuring blind area (Figure D shown below).

Extended reading: GWR Solid Level Sensor-Cement silo-Ash powder measure

Featured Tank Level Sensors

FAQ

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

A wide variety of Radar level Sensor for level measurement 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.

Request a Quote

Parabolic antenna

The parabolic antenna is suitable for both liquid and solid applications. As it has the largest diameter it has the most narrow radar beam and can be used for extremely long measuring distances. The parabolic is also the antenna type most insensitive to contamination. It can be used in applications with severe antenna condensation like asphalt and liquid sulphur.

The Rosemount 5900S antennas have a drip-off design which for some versions also include inclined polished PTFE surfaces. Condensation on the antenna is minimized, and the radar signal remains strong. This results in maintenance free operation, high accuracy and reliability.

There is always a suitable antenna for every tank type, tank opening and application:

• Parabolic
• Horn
• Still-pipe array
• LPG/LNG

Information Sources: https://www.emerson.com/documents/automation/product-data-sheet-rosemount-5900s-radar-level-gauge-en-104522.pdf

SIRD-904 Radar Level Gauge with Parabolic Antenna is a cheap alternative to Rosemount 5900S. If you have any technical questions, please contact our sales engineers.

Radar Antenna Types, please refer to:

SIRD-902 Drop Antenna Radar Tank Level Sensor

See more

FAQ

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Solid level measurement techniques

Solid level measurement is a challenge for everyone. Because the bulk solids detected in the silo or storage tank are irregular physical forms.

Solid level measurement is a very difficult task. But knowing the amount of bulk solids in a silo, storage tank, or other container is an important variable in any process. Manufacturers can maximize efficiency, prevent overflow, exhaustion, or track volume or quality.

The use and selection of the Solid level measurement instrument are more complicated. Because the tested medium is an irregular physical form. SIRD-903 26 GHz Radar level Sensor is suitable for Dust solid level measurement. It is used in solid materials, strong dust, easy to crystallize, and condensation. Such as calcium carbonate powder level measurement.

Extended reading: ​Solid flow meter | For bulk solids-powder-soybean-cement 

Common level sensors for solids

The analysis of common level sensor for solids is as follows:

No.	Type	Pros and cons
1	Rotary resistance level sensor	Advantages: more reliable; Limitations: Not durable.
2	Capacitive level sensor	Advantages: more durable; Limitations: Poor reliability.
3	Permanent magnet level sensor	Advantages: reliable, sensitive, and durable; Limitations: It must be installed vertically.
4	Ultrasonic level sensor	Advantages: non-contact. Limitations: Dust influence/concave-convex surface influence/noise non-contact type;
5	Radar level sensor	Advantages: non-contact. Limitations: required dielectric constant/dust influence/concave-convex surface influence; Recommendation: use a four-wire radar with a high transmitting frequency
6	Guided wave radar level sensor	Advantages: measurement of a certain point. Limitations: The dielectric constant has requirements/hanging materials/tension influence; Extended reading: GWR Solid Level Sensor-for Cement silo-Ash powder measure
7	Laser level sensor	Advantages: non-contact Limitations: Dust influence/concave-convex surface influence
8	RF admittance level sensor (capacitive level sensor)	Advantages: point contact Limitations: required dielectric constant/time drift/temperature drift/hanging material/tension;
9	Hammer type level sensor	Two types: cable type and belt type Advantages: direct measurement/manual control Limitations: traditional cable-type heavy hammers are prone to broken hammers, buried hammers, and messy ropes Recommendation: Belt type heavy hammer
10	Ray level sensor	Advantages: non-contact, stable Limitations: Pollution/High price
11	Weighing type level sensor	Advantages: can measure mass/volume Limitations: Anti-seismic problem / unknown material condition / high price

Extended reading: Radar Level Meter for Corrosive Liquids

Extended reading: GWR Solid Level Sensor-Cement silo-Ash powder measure

Featured level sensors for solids and liquids

FAQ

Extended reading: guided wave radar level sensor advantages and disadvantages

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

A wide variety of level sensor for solids level measurement 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.

Request a Quote

Radar Liquid Level Sensor Working Principle

The radar-level antenna emits narrow microwave pulses. Downward transmission via the antenna. After the microwave touches the surface of the measured medium, it is reflected back. It is received by the antenna system again and transmitted to the electronic circuit part to automatically convert it into a level signal.

Because microwaves travel so fast, the time it takes for electromagnetic waves to reach the target and return to the receiver by reflection is almost instantaneous.

A range setting
B Low adjustment
C high adjustment
D Blind zone range

The reference plane of the measurement is:
The bottom surface of the thread or the sealing surface of the flange

Note: When using radar level timing, make sure that the highest material level cannot enter the blind area of the measurement (the area shown in D in the figure).

Know more about Level measurement using radar technology

Radar Level Sensor Advantages and Disadvantages

Radar Level Sensor for Solids

Radar Level Sensor Price

The price of the radar level sensor is related to the medium, installation method, and pressure level.

1. The medium is divided into ordinary type and anti-corrosion type. The cost of the ordinary type is relatively low, and the price of the anti-corrosion type is relatively expensive.
2. The pressure levels are divided into 1.0MPA, 1.6MPA, 2.5MPA, 4.0MPA, 25MPA. The greater the pressure, the more expensive the price. So the pressure is directly proportional to the price.
3. Every customer who has bought a radar level sensor knows that the installation method is different. Top-mounted and side-mounted. Because of the different structure, the top-mounted type is more expensive than the side-mounted type.

Sino-Inst provides customers with the most reasonable prices on the basis of ensuring product quality. Radar Level Sensor Price reference range: USD500-1500.00/pc

Extended reading: ​Solid flow meter | For bulk solids-powder-soybean-cement 

Featured Radar Water Level Sensors

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

A wide variety of Microwave Radar Liquid 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.

Request a Quote

The working frequency band of Radar Tank Level Sensor is 24G~26GHZ. Radar Tank Level Sensor is a non-contact radar transmitter based on the principle of FM continuous wave.

Radar Antenna Types

1. Horn antenna for radar level gauge:
   26G high-frequency radar-type level measuring instrument. Output 4-20mA analog signal. The maximum measuring distance can reach 70 meters. This antenna has been further optimized. The new and fast microprocessor can perform higher-speed signal analysis and processing. The instrument can be used for particularly complex measurement conditions in reactors or solid silos.
2. Rod antenna for radar level gauge:
   Suitable for measuring liquids. Corrosive media. The maximum measuring distance can reach 20 meters. The antenna is further optimized. The new and fast microprocessor can perform higher rate signal analysis and processing. The instrument can be used for very complex measurement conditions in the reactor or solid silo.
3. Parabolic antenna for radar level gauge:
   This is a new type of antenna launched in China. It is mostly used in high-frequency transmitting radars. It is especially suitable for measuring targets and avoiding obstacles. 26G high frequency radar type level measuring instrument. Output 4~20mA analog signal. The maximum measuring distance can reach 70 meters. The antenna is further optimized. The new and fast microprocessor can perform higher rate signal analysis and processing. The instrument can be used for very complex measurement conditions in the reactor or solid silo.
4. Radar level gauge casing antenna:
   The casing has a focusing effect on radar waves. Therefore, when the dielectric constant is small or the liquid level produces continuous eddy currents or the device in the container causes false reflections, this type of instrument is suitable. But the measured medium is required to have good fluidity. It is not easy to hang the material.
5. Lens radar liquid level antenna:
   Transmits narrow microwave pulses and transmits downward through the antenna. The maximum measuring distance can reach 70 meters. The antenna is further optimized. The new and fast microprocessor can carry out higher-speed signal analysis and processing. The instrument can be used for some complex measurement conditions such as reactors and solid silos.

The above content is for your reference only. When choosing the antenna of the radar level gauge, you should choose according to the actual needs of the measurement environment.

Extended reading: Magnetostrictive Hydraulic Cylinder Position Sensor

Radar Tank Level Sensor Working Principle

Frequency Modulated Continuous Wave Technology (FMCW)

The drop-type antenna emits radar waves, which are received by the antenna after being reflected on the surface of the medium. The radar principle used is Frequency Modulated Continuous Wave (FMCW). The frequency modulated continuous wave (FMCW) radar sends out a signal in the high-frequency band. Within its measurement range, the frequency of the radar wave increases linearly (called frequency sweep).

The transmission and reception of radar waves correspond to a time difference t. The distance d between the radar and the surface of the medium conforms to the formula t=2×d/c. Where c is the transmission speed of the radar wave above the surface of the medium, that is, the speed of light.

SIRD-902 Drop Antenna Radar Tank Level Sensor performs signal processing by comparing the frequency difference between the reflected wave and the current transmitted wave. The frequency difference △f is proportional to the distance, and the greater the frequency difference, the greater the distance.

After Fast Fourier Transform (FFT), the frequency difference Δf is converted into a frequency spectrum, and the distance d is calculated from this. The height of the level is calculated by the given tank height.

Extended reading: Radar Level Meter for Corrosive Liquids

More Featured Radar Level Sensors

Level Senors for Tank Level Measurement

Tank level senor is a level sensor used to measure the tank level. The liquid level is the level of the liquid in a sealed container (such as a water tank) or an open container (water tank). The instrument that measures the liquid level is called a liquid level sensor, a liquid level gauge or a liquid level transmitter. The liquid level sensor is a kind of level instrument.

Hydrostatic, Ultrasonic, Magnetostrictive, Radar, Differential Pressure are commonly choices for tank level measurement. Liquid level sensors have been around for decades for leak detection or level measurement. Common measured mediums are: Water, Fuel, Diesel, Gasoline, diesel, liquefied gas, liquid ammonia, etc.

Read more about: 7 Level Senors for Tank Level Measurement

FAQ

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

A wide variety of Radar Tank 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.

Request a Quote

Silo Level Sensor is specially used for level measurement of solid material silos (including fine ore silos). Perfect Solutions for Silo Level Monitoring and Control.

Features of SI-FMF21 FMCW Radar Silo Level Sensor

• The 120GHz frequency modulated continuous wave radar level meter only needs 80ms to complete a complete measurement and calculation process for a distance of 100m. This allows the system to have more time and resources to deal with all kinds of things in meter level applications. For example: probability evaluation/prediction/credibility analysis/input/output/communication, etc.
• The PTFE lens antenna is fully enclosed and potted. It solves the structural treatment of the antenna near-field radiation suppression. This makes it have good directional performance. The beam angle is controlled within 1 degree. The manufacturing process difference of batch products , The deviation may be about ±0.3 degrees.
• The 120GHz frequency modulated radar level gauge is especially suitable for high temperature, high pressure or high dust, and multiple agitated spaces. It meets many measurement requirements that require a large range and high precision.
• Evaporation and dust will not affect the measurement;
• Level measurement of corrosive liquid, no contact, no corrosion-stable measurement;
• Liquid level measurement of foam and strong dust;

Specifications of SI-FMF21 FMCW Radar Silo Level Sensor

Measuring medium:	Liquid
Measuring range:	0.3m~150m
Process connection:	Flange≥DN80
Process temperature:	-40～110℃
Process pressure:	-0.1～0.3 MPa
Accuracy:	±5mm
Protection level:	IP67
Frequency Range:	123GHz
power supply:	Two-wire system (DC24V)/four-wire system (DC12V~24V)/four-wire system (AC220V)
Explosion-proof grade:	Exia ⅡC T6 Ga / Exd IIC T6 Gb
Housing:	Aluminum/plastic/stainless steel
Signal output:	Two-wire system 4…20mA/HART protocol Four-wire system 4…20mA/RS485 Mod bus

Radar Silo Level Sensor Applicaitons

Radar Silo Level Sensor is suitable for high temperature and high-pressure reactor, super large storage tank, and still tube measurement.

Radar Silo Level Sensor is suitable for high-precision metrological measurement and perspective measurement.

Radar Silo Level Sensor is suitable for extremely harsh working conditions such as strong dust and steam, and storage tanks with special processes such as stirring and heating rods.

Extended reading: GWR Solid Level Sensor-for Cement silo-Ash powder measure

Solutions for Silo Level Monitoring and Control

Cement Silo Level Indicator

Cement industry material process storage level detection. Including clinker warehouse, raw meal homogenization warehouse, raw material mixing warehouse, limestone storage warehouse, raw coal warehouse and cement mixing warehouse, etc.

First, the cement silo (tank) liquid level sensor is a sensor used to detect the height change of the material in the container. It can continuously detect the height, volume and other values ​​of the material, and transmit the relevant information to the computer or display instrument.

Secondly, the cement tank liquid level sensor is mainly used to automatically detect and control the limit material level of various materials (such as powder, granules or blocks). Different types of material straightening machines can meet the requirements of different working conditions.

Furthermore, in the concrete mixing equipment, the cement tank is a closed storage device. The user cannot intuitively understand the amount of powder in it, and a liquid level sensor is needed at this time.
The liquid level sensor in the cement tank can accurately record the position of the material in the cement tank for easy management.

Lime Silo Level Sensor

As a multifunctional product, lime is not only used to purify raw materials, but also often used to clean and neutralize waste water from sugar beets. The resulting by-products are also useful because it contains a mixture of lime and organic residues. They are usually reused as soil additives and conditioners in agriculture and are rich in organic matter.

Most sugar processing plants have their own lime kilns, which require good high-purity limestone to burn. This “high calcium” limestone is converted into quicklime in a lime kiln at a temperature of 900°C. In order to obtain the milk of lime, the “calcined” lime is mixed into the water. In this process, accurate and reliable level measurement can ensure consistent production.

The processing area must have a high level of safety. Because lime is harmful, especially irritating to the skin and eyes. All outer surfaces of the radar level gauge are of plastic or stainless steel construction, with a fully enclosed PTFE antenna system. This means that in this highly alkaline environment, the sensor will have minimal corrosion and a longer service life.

Extended reading: Radar Level Meter for Corrosive Liquids

Featured Silo Level Monitoring Systems

FAQ

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High temperature level sensor is based on FMCW Radar to measure high temperature liquid. Non-contact measurement. The temperature is as high as 240°C. IP67 protection. rs485 output.

Advantages of FM Radar Level Meter

FMCW radar level meter is suitable for various complex working conditions. It can also ensure measurement stability and accuracy in high temperature and high dust environments.

• Not affected by atmospheric precipitation;
• Ambient temperature from -60℃;
• from outside the storage tank;
• The inner antenna of the terahertz FM continuous wave radar level meter is heated and protected by a fluoroplastic lens
• The measurement beam is narrow. Easy installation and stable measurement;
• Level measurement accuracy;
• Not limited by the temperature in the container;
• Evaporation and dust do not affect the measurement;
• Boiling liquid level measurement;
• Corrosive liquid level measurement. No contact, no corrosion;

FMCW Radar Working Principle

In the early years, a non-contact frequency-modulated continuous wave radar level meter produced by a company in the United States used FMCW technology to perform more accurate level measurement for more complex occasions. This FMCW technology has caused a global sensation. It has made more researchers devote themselves to FMCW technology. FMCW here is frequency modulated continuous wave.

This FMCW radar technology uses a high frequency sweep signal typically 8.5 to 9.9 GHz. The radar signal is sent from one end of the antenna and is received by the receiver after time t. The frequency difference Δf between the transmitting and receiving is converted into the level of the measured medium by the Fourier transform method.

However, with the development of the times and the efforts of scientific researchers, the continuous waves of 26GHz, 28GHz, 80GHz and 120GHz have been derived from the FM continuous wave radar level gauge.

FM continuous wave radar level meter is a general-purpose instrument for measuring coal, cement, grain, alumina, limestone, chemical raw materials and other materials. It is widely used in cement, chemical, environmental protection, electric power, food and other industries.

The 120GHz radar level meter is especially suitable for high temperature, high pressure or high dust, and multi-stirring environments. It meets many measurement requirements that require a large range and high precision.

Terahertz FM CW radar level meter mainly uses triangular FM continuous wave. After the transmitted signal is scattered by the target, it is accepted by the antenna. The delay time τ=2R/c. Among them, R is the distance from the target to the antenna, and c is the propagation speed of the electromagnetic wave. .

When the detection target is stationary, the distance calculation formula is R=(cT/4B)×fb, where T is the period of the triangular wave, and B is the frequency modulation bandwidth.

From the formula R=(cT/4B)×fb, it can be obtained that the frequency fb of the beat frequency signal has a linear relationship with the distance R. Therefore, the key to the ranging system is to measure the frequency of the beat frequency signal.

Under certain conditions of bandwidth B and period T, the distance R can be calculated as long as the frequency fb is obtained. Therefore, the accuracy of frequency measurement directly affects the accuracy of distance measurement.

The difference frequency signal is usually sampled by A/D and then calculated by FFT to obtain the discrete spectrum of N points. Then fb is obtained by the peak frequency of the spectrum. Because the discrete spectrum will have a frequency domain sampling interval △f=fs/N.

In the formula, fs is the sampling frequency, and N is the number of sampling points.

The discrete spectrum sampling obtained by FFT generally cannot collect the peak point of signal frequency. That is, the integer multiple of the frequency interval does not coincide with the peak point, which causes the result of FFT analysis to be inconsistent with the actual frequency, resulting in frequency estimation error.

Extended Reading: Case: High Temperature Radar Level Transmitter for Melted Salt-Solar Photovoltaic Power Station

Level Measurement with FMCW Radar in Steam and High Temperature

When the measured medium is heated, or stored products with relevant physical and chemical properties (acids, alkalis, alcohols, etc.), there may be vapor accumulation in the upper space of the measured medium.

There are various vapors in the air in the space between the level gauge and the medium. It will not affect the accuracy and stability of the measurement. The FM continuous wave radar level gauge has this characteristic.

Level measurement by means of ultrasonic or optical (laser) means is a very unstable and inaccurate method. Because the speed of sound propagation depends on the composition of the atmosphere through which it passes. Direct optical visibility is required for measurement by laser means.

Level Sensors for High Temperature Applications

High Temperature Float Switch

Float level sensor can be widely used for continuous measurement of the liquid level (boundary level): High temperature. High pressure. Viscous, dirty media. Asphalt, wax-containing oil products and flammable, explosive, corrosive media.

Intelligent Solutions for High Temperature and Pressure

Related Blogs

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

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

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

Request a Quote

Radar Water Level Sensor for Non-contact water level measurement. Two-wire system 4…20mA/HART protocol; four-wire system 4…20mA/RS485 Mod bus. Explosion-proof Exia ⅡC T6 Ga / Exd IIC T6 Gb.

Features of SI-FMF13 FMCW Radar Water Level Sensor

• 120GHz (ISM standard band) distance detector based on the working principle of radar.
• FMCW planar microstrip radar non-contact detection. Stable working all-weather.
• The measurement error is less than ±1cm.
• Radar antenna style: 11º×11º. Good directivity, low transmission loss.
• Standard data communication interface (RS-232/RS-485) can be set.
• Low power consumption, waterproof and lightning protection design. Suitable for various outdoor environments.
• Small appearance. Easy to install and easy to maintain.

Specifications of SI-FMF13 FMCW Radar Water Level Sensor

Measuring medium:	Liquid
Measuring range:	0.1m~100m
Process connection:	Flange≥DN80
Process temperature:	-40～110℃
Process pressure:	-0.1～0.3 MPa
Accuracy:	±5mm (range between 35m-100m) ±2mm (range under 35m)
Protection level:	IP67
Frequency Range:	123GHz
power supply:	Two-wire system (DC24V)/ four-wire system (DC12V~24V)/four-wire system (AC220V)
Explosion-proof grade:	Exia ⅡC T6 Ga / Exd IIC T6 Gb
Housing:	Aluminum/plastic/stainless steel
Signal output:	Two-wire system 4…20mA/HART protocol Four-wire system 4…20mA/RS485 Mod bus

Lake Water Level Sensor

Radar water level sensor monitors the water level of rivers, lakes, tidal water reservoirs and reservoirs.

Solution requirements:

The radar water level sensor monitors the water level of rivers, lakes, tidal water reservoirs and reservoirs. It is suitable for installation and use in areas that are not convenient for wiring due to corrosion, pollution, and flood-related water level collection.

Transmit a short microwave pulse, and then measure the elapsed time between pulse transmission and return. The running time of a few meters is measured in units of nanometers. Therefore, a special time conversion program is required to accurately measure these short time periods.

The elapsed time measurement is used to calculate the distance between the sensor and the target (for example, water, grain, slurry). The distance value can then be used to determine the depth of the medium.

Extended reading: Radar Non Contact Water Level Sensor

Technical Support:

Pulse radar level transmitters provide water level measurement based on directly measuring the running time of microwave pulses transmitted to and reflected from the surface of the river being measured. Using rs485 two-wire signal transmission, power supply and low power consumption are safe for outdoor use.

RS485 interface can be connected with 485 line, insert 4g sim card in dtu. 232 to usb to connect to the computer. Open the configuration tool and set the server address and port in the dtu configuration tool.

The server port monitors to receive the data, and it can be analyzed according to the sensor protocol. If the platform is developed to the modbus standard, the sensor also supports modbus. The whole analysis process will be simpler.

Realize remote monitoring and management of liquid level and water level outdoors. Both dtu and sensor industrial-grade outdoor design can be powered by solar energy. Therefore, radar water level gauges can be used in some of the most challenging water level applications.

Advantages:

• dtu rs485 bus access. Multi-device access, support rs232 interface;
• Strong compatibility. Can be connected to five-parameter water quality equipment. Multiple sensors use one gateway;
• Installed on the shore of the water area, on the measuring frame or “extension arm”. Adjust the mounting bracket according to the terrain;
• The installation is simple and the price is low. No need for expensive installation procedures;
• Low power consumption power supply enables the equipment to operate independently in the most remote areas;
• Non-contact measurement principle. Not damaged by silt accumulation or debris;
• Wireless transmission, avoid the trouble of pulling cables. Install and use, remotely unattended;
• High-level industrial requirements for the appearance of the iron shell. Application in hazardous areas and harsh environments;

Extended reading: Capacitive water level sensor

More Water Level Sensors

Sino-Inst offers a variety of water level sensors for a wide range of conditions. Our sensors are ideally suited for monitoring water levels in streams, dams, and reservoirs. Our water level sensor products include:

• Submersible Pressure Transducers
• Radar Level Sensors
• Magnetostrictive Level Sensors
• Pressure Transducers
• Ultrasonic water level sensor

Sino-Inst offers over 10 FMCW Radar Water Level Sensor for level measurement. About 50% of these are float liquid level meters, 40% is the Solid level sensors.

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

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

Request a Quote

Frequency modulated continuous wave radar also known as FMCW radar. Frequency modulated continuous wave radar level sensors antenna has been further optimized. The new and fast microprocessor can perform higher rate signal processing.

Features of FMCW Radar Level Sensor

• 120GHz-130GHz FM wave radar. Terahertz radar used in industrial measurement field
• 10GHz ultra-large FM scanning frequency width. Wide application range
• 320*240dot TFT color LCD display. Easy to operate and friendly interface
• Support standard HART, MODBUS, PROFIBUS bus protocol
• Support multiple operation and configuration methods such as PC setting software, mobile phone APP, LCD keyboard module, tank side meter, etc.
• 24VDC, 220VAC two power supply models
• Simple installation structure. Adapt to various installation forms on site

Specifications of SI-FMF12 FMCW Radar Level Sensor

Measuring medium:	Liquid
Measuring range:	0.05m~35m
Process connection:	G2A thread/flange≥DN65
Process temperature:	-40～110℃
Process pressure:	-0.1～1.6 MPa
Accuracy:	±2mm
Protection level:	IP67
Frequency Range:	IP67
power supply:	Two-wire system (DC24V)/four-wire system (DC12V~24V)/four-wire system (AC220V)
Explosion-proof grade:	Exia ⅡC T6 Ga / Exd IIC T6 Gb
Housing:	Aluminum/plastic/stainless steel
Signal output:	Two-wire system 4…20mA/HART protocol Four-wire system 4…20mA/RS485 Mod bus

Extended Reading: Influence of Dielectric Constant on Liquid Level Measurement | Radar-Guided Wave Radar Level Meter

Frequency modulated continuous wave radar pros

120GHz-130GHz FM wave FMCW radar product (also called THz terahertz radar).
It uses a higher frequency THz band than Ku-band radar.

It has important applications in remote target detection, strong smoke and dust environment, long-distance imaging, multi-spectral imaging, etc. And can detect smaller targets than microwave radar and achieve more precise positioning. With higher resolution and stronger confidentiality.

What are terahertz (THz) electromagnetic waves?

It refers to electromagnetic waves and electromagnetic radiation with electromagnetic wave frequency between 100GHz ~ 10,000GHz (10THz).

This band is the area that humans have the least understanding and application development so far. Terahertz lies between mid-infrared and microwave on the electromagnetic spectrum, and represents the transition stage from quantum mechanism transmission theoretical physics to classical mechanism transmission theoretical physics.

1THz(=1000GHz) The wavelength of electromagnetic wave is 300um (0.3mm is about the diameter of human hair)

Difference between CW radar and FMCW radar

Radars are divided into pulse radars and continuous wave radars according to the types of transmitted signals. Conventional pulse radar emits periodic high-frequency pulses. Continuous wave radar emits continuous wave signals.

The signal emitted by continuous wave radar can be single frequency continuous wave (CW) or frequency modulated continuous wave (FMCW). There are also many ways of frequency modulation. The common ones are triangle wave, sawtooth wave, code modulation or noise frequency modulation.

Among them, the single-frequency continuous wave radar (CW) can only be used for speed measurement, not distance measurement. The FMCW radar can measure both range and speed, and its advantages in short-range measurement are becoming increasingly obvious.

From Wikipedia, we can learn more about Continuous-wave radar.

Frequency Modulated Continuous Wave Radar Working Principle

FM wave radar level sensor and distance formula:

Among them: C speed of light; fd Doppler frequency shift; fu triangle rising edge difference frequency; f0 FM initial frequency; T signal period; B signal bandwidth

The distance resolution depends on the frequency resolution of the DFT operation (Frequency Resolution). The frequency resolution of the DFT Fres is equal to:

①

T is the corresponding sampling time of the non-zero sampling value used for the DFT operation. If you use FFT + zero padding method to calculate the spectrum. T is the time corresponding to the sampled value of the non-zero-filled point.

The distance corresponding to the frequency resolution Fres is the range resolution Sres of the radar. Then, how to calculate the range resolution of the FMCW radar?

B: Frequency modulation width, unit Hz

T: Actual frequency modulation, in seconds

C: Speed of light, 3*10^8 meters/second

S: the distance between the radar and the object, meters

V: Frequency modulation speed, Hz/sec

t: wave propagation time, sec

V=BW/T  ②

t= 2S/C   ③

Assume that T is sampling during the entire frequency modulation period. And all sampling points are used for DFT calculation. According to ④ and ①,

which is

This is the calculation formula for the minimum range resolution that FMCW can obtain when the frequency modulation bandwidth is determined.

In actual use, the sampling time will be slightly shorter than the actual frequency modulation T. That is, Fres will be larger in value. So Sres will also become larger in value.

FMCW vs Pulse radar

VEGAPULS has a good explanation video about PULSE and FMCW technology | Radar level measurement. Let’s take a look together.

Video source: https://www.youtube.com/watch?v=eAngy1B1FP

Pulse Radar

Pulse radar is a precision tracking radar. Each time it emits a pulse, the antenna can form several beams at the same time, and compare the amplitude and phase of the echo signal of each beam.

When the target is located on the antenna axis, the amplitude and phase of the echo signal of each beam are equal, and the signal difference is zero.

When the target is not on the antenna axis, the amplitude and phase of the echo signals of each beam are not equal, resulting in signal difference.

Drive the antenna to the target until the antenna axis is aligned with the target, so that the high and low angle and azimuth angle of the target can be measured.

The sum of the signals received by each beam can measure the distance of the target. In order to realize the measurement and tracking of the target.

FMCW

FM continuous wave radar refers to a continuous wave radar whose transmitting frequency is modulated by a specific signal, such as weather radar.

FM continuous wave radar obtains the distance information of the target by comparing the difference between the frequency of the echo signal at any time and the frequency of the transmitted signal at that time.

The distance is proportional to the frequency difference between the two. The radial velocity and distance of the target can be obtained by processing the measured frequency difference between the two.

Compared with other range and speed measurement radars, the structure of FM continuous wave radar is simpler.

FMCW radar has rich technical experience, low transmit power peak required, easy modulation, low cost, and simple signal processing, so it is a commonly used radar system in automotive radars.

LFMCW radar, i.e., the carrier signal frequency changes linearly with time.

FAQ

Sino-Inst offers over 10 FMCW Radar Level Transmitters for level measurement. About 50% of these are float liquid level meters, 40% is the Solid level sensors.

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

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

Request a Quote