In industrial systems, accurately measuring and monitoring the level of liquids or materials in storage tanks, process tanks, and storage equipment is an important factor in ensuring stable operation. A suitable level measuring device must not only meet the required measuring range but also provide appropriate accuracy, signal transmission capability, and reliability for the operating environment.

F&V Intelligent Instrument Radar Level Meter FRL21 Series is a Radar level measurement sensor designed for liquid and material level measurement applications. According to the product documentation, the FRL21 Series uses microcomputer processing technology, supports multiple Radar frequencies, various probe options, and signal transmission methods such as 4–20 mA, HART, and RS485. The device offers selectable measuring ranges from 0–5 m to 0–70 m, 1 mm resolution, and IP67 protection.

1. Overview of the F&V Intelligent Instrument Radar Level Sensor

1.1. What is a Radar Level Sensor?

A Radar Level Sensor (Radar Level Meter) is a device that uses Radar waves to determine the level of a medium or material within a measurement space. In industrial systems, Radar Level Meters are used to monitor the level inside tanks and storage vessels and provide signals to control and monitoring systems.

Unlike level measuring devices that use mechanical mechanisms or probes directly contacting the medium, a Radar Level Meter primarily uses transmitted and received Radar signals to determine the position of the measured surface.

For systems requiring continuous level monitoring, the use of a Radar Level Meter allows level information to be transmitted to a controller or monitoring system through signals such as 4–20 mA, HART, or RS485.

1.2. Introduction to the F&V Intelligent Instrument FRL21 Series

The F&V Intelligent Instrument FRL21 Series is a Radar Level Meter designed for liquid and material level measurement.

According to the technical documentation, the FRL21 Series supports 6.3 GHz, 26 GHz, and 80 GHz frequencies, with selectable measuring ranges from 0–5 m, 0–10 m, 0–20 m, 0–30 m to 0–70 m, depending on the configuration. The device provides an accuracy of ±2 mm or ±5 mm, repeatability of ±0.1%, and resolution of 1 mm.

In addition, the FRL21 Series features a 2-line LCD with an integrated Echo Graph, four operating buttons, and an integrated temperature compensation function. The device also provides IP67 protection and an explosion-proof configuration option according to the product documentation.

2. Operating Principle of the Radar Level Sensor

2.1. Radar Wave Transmission and Reception

A Radar Level Meter operates based on the principle of transmitting and receiving electromagnetic waves.

The device transmits a Radar signal toward the surface of the medium or material being measured. When the signal reaches the material surface, part of the energy is reflected back toward the sensor.

The device then processes the reflected signal to determine the distance from the sensor installation point to the measured surface.

2.2. Determining the Distance to the Liquid Surface

The measurement process can be illustrated as follows:

Radar signal transmission → signal travels to the surface → reflected signal → sensor receives Echo → signal processing → distance determination → level calculation.

Once the distance between the sensor and the surface has been determined, the device can use this distance to calculate the level based on the installation position and the configured measuring range.

The FRL21 Series provides liquid level display in millimeter and percentage units, allowing operators to conveniently monitor the status of a tank or vessel.

2.3. Converting Distance into Level Value

Assuming the reference height of the tank is H and the measured distance from the sensor to the medium surface is D, the level can be determined based on the relationship:

Level = H – D

In actual applications, parameters such as tank height, measurement zero point, and measuring range need to be configured appropriately according to the actual system configuration.

2.4. Factors Affecting Measurement Signals

The stability of Radar measurement may depend on the characteristics of the medium, tank configuration, installation position, and internal operating conditions.

Therefore, when selecting the FRL21 Series, the following factors should be considered together:

• Required measuring range.
• Type of medium or material.
• Operating temperature and pressure.
• Installation position.
• Probe type.
• Radar frequency.
• Connection type.
• Signal and communication requirements.

3. Key Features of the FRL21 Series Radar Level Meter

3.1. Liquid and Material Level Measurement

The FRL21 Series documentation states that the device can be used for Liquid Level, Material Level, Dust, and Particles, thereby expanding the application range of the Radar Level Meter in industrial systems.

This allows users to select an appropriate configuration depending on the measurement environment and the type of material being monitored.

3.2. Multiple Frequency Options: 6.3 GHz, 26 GHz, and 80 GHz

The FRL21 Series supports three main frequency options:

• 6.3 GHz
• 26 GHz
• 80 GHz

The availability of multiple frequency options provides different configuration possibilities for level measurement applications. However, frequency selection should be based on the actual application requirements rather than simply selecting the highest available frequency.

3.3. Accuracy and Repeatability

According to the product documentation, the FRL21 Series provides:

• Accuracy: ±2 mm / ±5 mm
• Repeatability: ±0.1%
• Resolution: 1 mm

These specifications indicate that the device is designed for applications requiring relatively high-resolution level monitoring.

3.4. Integrated Temperature Compensation

The FRL21 Series is equipped with a temperature compensation function, allowing the device to compensate for temperature effects during measurement according to the product configuration.

This function is useful for systems where operating temperature varies during operation.

3.5. 2-Line LCD and Echo Graph

The device is equipped with a 2-line LCD and an integrated Echo Graph.

In addition to displaying the measured value, the Echo Graph allows operators to observe the Radar return signal during inspection and configuration.

The FRL21 also features four integrated buttons for operation and display control.

3.6. IP67 Protection and Explosion-Proof Option

According to the documentation, the FRL21 Radar Level Meter provides IP67 protection. The product also offers an Ex d IIC T6 Explosion-proof Grade option according to the configuration shown in the documentation.

When used in hazardous areas requiring explosion protection, the correct certified configuration must be selected and the complete installation requirements of the system must be verified.

4. Technical Specifications of the FRL21 Radar Sensor

The following table summarizes the specifications shown in the product documentation:

The above values are summarized from the Specification Parameters table and the FRL21 Series product description in the documentation provided.

5. Probe Types and Configuration Options

One of the notable features of the FRL21 Series is its multiple probe and material options.

5.1. Horn Type

Horn Type is one of the probe configurations available for the FRL21 Radar. This probe type can be selected based on the required measuring distance and characteristics of the measurement environment.

5.2. Rod Type

Rod Type features a rod-shaped probe and is one of the probe options available for the FRL21 Series.

5.3. Cable Type

Cable Type uses a cable-style probe and is suitable for configurations where the probe needs to be positioned at a certain depth within the equipment.

5.4. Pole Type

Pole Type is another probe option listed in the FRL21 product range.

5.5. Conical and Arc-shaped

The documentation also lists Conical Type and Arc-shaped Type, providing users with additional options when determining the equipment configuration.

5.6. PTFE, SUS304, and SUS316 Materials

The FRL21 Series supports the following probe material options:

• PTFE
• SUS304
• SUS316

Material selection should be based on the chemical properties, temperature, and operating conditions of the actual medium.

For applications involving corrosive media or requiring specific wetted materials, selecting an appropriate probe material is one of the important steps when configuring the sensor.

6. Signal and Communication of the FRL21 Radar Level Meter

6.1. 4–20 mA Signal Output

The FRL21 Series supports 4–20 mA signal output.

This is a common signal type in industrial measurement and control systems, allowing the measured value from the sensor to be transmitted to a PLC, DCS, or other compatible control devices.

6.2. HART Communication

In addition to the 4–20 mA signal, the device supports HART communication.

HART can be used in systems requiring device communication and configuration through the corresponding signal line.

6.3. RS485 Communication

The FRL21 also supports RS485, providing an additional connection option for control systems or monitoring devices using compatible serial communication.

6.4. Application in Control and Monitoring Systems

With 4–20 mA, HART, and RS485 options, the sensor can be integrated into control systems according to the requirements of each project.

A basic configuration can be illustrated as:

Radar Level Meter → Signal/Communication → PLC/DCS → HMI/SCADA → Operator

In this configuration, the level value is measured by the sensor and transmitted to the control system for monitoring and subsequent control functions.

7. Advantages of the F&V Radar Level Sensor

Based on the configuration and specifications in the documentation, the F&V Intelligent Instrument FRL21 Series offers several notable features:

Multiple Measuring Ranges

Users can select measuring ranges from 0–5 m to 0–70 m, supporting various tank sizes and different level measurement requirements.

Multiple Frequency Options

The three options of 6.3 GHz, 26 GHz, and 80 GHz provide additional configuration possibilities for different applications.

1 mm Resolution

The FRL21 Series provides a specified resolution of 1 mm, making it suitable for applications requiring detailed monitoring of level changes.

Multiple Probe and Material Options

PTFE, SUS304, and SUS316 materials, together with multiple probe types, provide greater configuration flexibility.

Multiple Signal Transmission Options

The device supports 4–20 mA, HART, and RS485, facilitating integration into industrial control systems.

IP67 Protection

The IP67 protection level makes the device suitable for industrial equipment protection requirements according to the product configuration.

8. Applications of Radar Level Meters in Industry

The FRL21 Series is designed for measuring liquid and material levels, while the documentation also refers to Dust and Particles environments.

Potential application groups include:

8.1. Liquid Storage Tanks

Radar sensors can be used to monitor the level in industrial liquid storage tanks when the equipment is properly configured for the measurement medium.

8.2. Water Tanks and Water Treatment Systems

In water treatment systems, level measurement helps monitor the water level in tanks and supports automatic control systems.

8.3. Chemical Storage Tanks

When used for chemicals, special attention should be paid to probe material, temperature, pressure, and the properties of the medium.

The FRL21 provides probe material options such as PTFE, SUS304, and SUS316, allowing configuration selection according to the application requirements.

8.4. Industrial Tanks and Process Equipment

Tanks, vessels, or equipment requiring continuous level monitoring can be considered as potential applications for Radar Level Meters.

8.5. Material Level Measurement

According to the documentation, the FRL21 is specified not only for Liquid Level but also for Material Level, Dust, and Particles. Therefore, configuration selection should be based on the actual characteristics of the material and measurement requirements.

9. Guidelines for Selecting a Suitable Radar Sensor

Selecting a Radar Level Meter should not be based solely on price or measuring range. The overall system conditions should be evaluated.

9.1. Determine the Measuring Range

This is the first parameter that should be determined.

The FRL21 Series provides the following options:

0–5 m → 0–10 m → 0–20 m → 0–30 m → 0–70 m

Therefore, the actual distance from the installation position to the required measurement zone should be determined before selecting the configuration.

9.2. Select the Radar Frequency

The FRL21 supports:

• 6.3 GHz
• 26 GHz
• 80 GHz

It should not be assumed that a higher frequency is always more suitable. Selection should be based on the actual application, tank structure, and measurement requirements.

9.3. Select the Probe Material

If the medium is corrosive or has specific material compatibility requirements, the following should be considered:

• PTFE
• SUS304
• SUS316

Selection must be based on the actual compatibility between the material and the medium.

9.4. Select the Installation Method

The FRL21 Series supports the following installation methods shown in the documentation:

• Thread
• Flange
• Clamp

When selecting the installation method, connection dimensions, nozzle position, and available installation space should be checked.

9.5. Consider Temperature, Pressure, and Environment

According to the documentation:

• Ambient temperature: -40 to +70°C
• Pressure rating: 1.6 MPa, Special Consultation
• Humidity: <95%
• Protection Level: IP67

For applications with conditions outside the standard range, the specific configuration should be verified with the supplier before selection.

9.6. Select the Signal and Communication

If the system uses an analog signal for PLC/DCS integration, 4–20 mA can be considered.

If digital device communication is required, HART or RS485 can be considered depending on the system configuration.

10. Important Notes for Installing and Operating the Radar Sensor

To ensure stable operation of the Radar sensor, installation should be carried out based on the actual conditions of the tank or equipment.

Select an Appropriate Installation Position

The installation position should be suitable for the Radar measurement direction and reflection area. Objects inside the tank that may affect the reflected signal should be minimized where possible.

Properly Determine the Zero Point and Measuring Range

Errors in setting the reference point or measuring range may result in deviations in the displayed level value.

Verify the Probe Type

The correct probe type should be determined before ordering and installation, especially when the application has specific requirements regarding material, measuring distance, or environmental conditions.

Check the Output Signal

After installation, the 4–20 mA signal and HART/RS485 communication, if used, should be checked. The displayed value should also be compared with the actual operating condition of the system.

Check Temperature and Pressure Conditions

The device should not be operated outside the specified operating conditions for the selected configuration. For applications requiring special pressure or explosion-proof requirements, the correct configuration should be confirmed before commissioning.

11. Why Choose the F&V Intelligent Instrument FRL21 for Level Measurement Systems?

In an industrial system, a level sensor does not only display the measured value but also serves as an input data source for the control system.

A suitable sensor needs to ensure compatibility between:

Medium → Measuring Range → Probe → Frequency → Temperature/Pressure Conditions → Signal → Control System.

F&V Intelligent Instrument FRL21 Series provides multiple options across these parameters. The device offers a measuring range of up to 70 m, three Radar frequency options, multiple probe types, PTFE/SUS304/SUS316 materials, 1 mm resolution, IP67 protection, and 4–20 mA, HART, and RS485 signal transmission options.

Therefore, the FRL21 Series can be considered for various level measurement applications in industrial systems, provided that the device configuration is properly selected for each specific application.

12. FRL21 Series Selection Summary

The above table is summarized from the FRL21 Series configuration and specifications in the product documentation.

13. Conclusion

The F&V Intelligent Instrument FRL21 Series Radar Level Sensor is a Radar Level Meter designed for measuring liquid and material levels in industrial applications.

The key features of the FRL21 Series include a measuring range from 0–5 m to 0–70 m, 6.3 GHz/26 GHz/80 GHz frequency options, multiple probe types, PTFE/SUS304/SUS316 probe materials, ±2 mm or ±5 mm accuracy, 1 mm resolution, and IP67 protection. The device also supports 4–20 mA, HART, and RS485, facilitating integration into industrial measurement, control, and monitoring systems.

However, selecting the correct Radar sensor should not be based on a single specification. Measuring range, frequency, probe type, material, medium, temperature, pressure, installation method, and communication requirements should all be considered together.

With the appropriate configuration, the F&V Intelligent Instrument FRL21 Series can be a suitable option for systems requiring level measurement and monitoring in industrial tanks, vessels, and process equipment.

ANCES can support customers in selecting the appropriate Radar Level Meter configuration based on the medium type, tank height, measuring range, temperature, pressure, connection type, and control signal requirements of each system.