Radar level Transmitter

80 GHZ RADAR LEVEL TRANSMITTER BRLT001

Measurement principle

1. Continuous Wave Signal:

○ FMCW systems continuously emit a signal that is modulated in frequency

over time. Unlike pulsed radar systems, which emit short bursts of signals,

FMCW systems generate a constant waveform.

2. Frequency Modulation:

○ The emitted signal frequency is varied (modulated) in a linear fashion over

a specified period. This modulation typically follows a triangular or

sawtooth waveform, where the frequency increases and then decreases.

3. Echo Reception:

○ When the emitted signal impacts a liquid or powder surface, part of the

signal is reflected back to the transmitter. The time it takes for the signal to

travel to the target and back is used to determine distance. In the FMCW

technology, beat frequency of reflected wave is used for this purpose.

4. Beat Frequency:

○ The received echo signal will have a frequency that differs from the

transmitted frequency because of the time delay in the round trip. The

difference in frequency between the transmitted (brown curve) and received

signal (green curve) is called the beat frequency.

○ The beat frequency is directly related to the distance to the target: fb=2d/c

○ where:

■ fb = Beat frequency

■ d = Distance to the target

■ c = Speed of electromagnetic wave in the mediu

80 GHZ RADAR LEVEL TRANSMITTER BRLT001

5. Distance Calculation:

○ The system measures the beat frequency and uses it to calculate the

distance to the target. Since the modulation is linear, the relationship

between the frequency shift and distance is linear, allowing for accurate

measurement. Due to frequency modulation, FMCW devices are robust

against losses during roundtrip of electromagnetic waves. Therefore

environmental effects can not degrade the performance of level

measurement.

Key Features

● High Frequency: Typically operates in the 80 GHz range, allowing for smaller antennas and

narrow beam angles.

● Millimeter Accuracy: Offers high precision, with measurements typically within a few

millimeters.

● Non-Contact Measurement: Measures levels without physical contact with the medium,

reducing maintenance needs and extending equipment life.

● Robust Signal Processing: Advanced algorithms minimise false echoes and provide reliable data

even in challenging conditions.

● Wide Measurement Range: Suitable for a variety of applications, from small containers to large

tanks, up to 100 metres 

Tank Farm

Mounting Considerations

Mounting radar level transmitters correctly is crucial for optimal performance and accurate

measurements. Here are key considerations and common mounting options:

1. Location:

○ Avoid Obstructions: Ensure that the radar beam path is clear of obstacles, such as pipes

or structural elements, which could cause false echoes.

○ Optimal Height: Mount the transmitter at a height that allows for the full measurement

range without interference.

2. Angle:

○ Vertical Mounting: Generally, radar transmitters are mounted vertically to ensure

accurate level readings.

○ Tilt: If tilting is necessary, keep it to a minimum to maintain the effectiveness of the

beam.

3. Environment

○ Vibration: Avoid mounting in areas with excessive vibration, which can affect accuracy.

○ Temperature and Pressure: Ensure the mounting location meets the transmitter’s

specified temperature and pressure ratings.

4. Access for Maintenance:

○ Easy Access: Choose a location that allows for easy access for maintenance and

calibration.

Common Mounting Options

1. Flanged Mounting:

○ Description: A flange is used to secure the transmitter to a tank or vessel.

○ Advantages: Provides a secure and stable installation, suitable for high-pressure

applications.

2. Threaded Mounting:

○ Description: Transmitter is screwed directly into a threaded opening on the tank.

○ Advantages: Simple installation, often used for smaller tanks and applications.

3. Hygienic Mounting:

○ Description: Used in food and pharmaceutical industries, often featuring sanitary fittings.

○ Advantages: Complies with hygiene standards and is easy to clean.

4. Side-Mounting:

○ Description: Mounted on the side of the tank, typically used for smaller tanks where top

access is limited.

○ Advantages: Useful for applications with limited vertical space.

5. Bracket Mounting:

○ Description: The transmitter is mounted on a bracket, allowing for flexible positioning.

○ Advantages: Ideal for portable or adjustable installations.

Key Considerations for Mounting Radar Level Transmitters in High-Temperature

applications:

1. Temperature Rating:

○ Ensure the transmitter is rated for the specific temperature range of your application.

Common high-temperature models can handle up to 200 °C or more by special mounting

adapter and purge system.

2. Material Compatibility:

○ Use materials that can withstand high temperatures and are compatible with the process

media. This may include high-grade stainless steel or specialized alloys.

3. 

○ If the application involves extreme temperatures, consider using insulation around the

mounting area to protect the transmitter from excessive heat.

4. Vibration and Shock:

○ Ensure the installation minimizes exposure to vibration and shock, as high temperatures

can affect the integrity of both the transmitter and the mounting.

5. Clearance for Heat Expansion:

○ Allow for thermal expansion of the transmitter and associated piping. Ensure that

mounting allows for movement without causing stress on the transmitter.

6. Beam Path:

○ Maintain a clear path for the radar beam. Avoid obstructions that could interfere with the

measurement, particularly in high-temperature environments where vapor or steam may

be worse.

Common Mounting Options for High-Temperature Applications

1. Flanged Mounting:

○ Description: Use a high-temperature-rated flange in association with a special adapter to

secure the transmitter to the vessel.

○ Advantages: Provides a robust and secure installation suitable for high-pressure and

high-temperature applications.

2. Threaded Mounting:

○ Description: Screw the transmitter into a high-temperature-rated threaded opening by a

special high temperature adapter.

○ Advantages: Simple and effective for installations where flanging is impractical.

3. Thermal Well:

○ Description: Use a thermal well to house the radar transmitter, providing additional

protection against extreme temperatures.

○ Advantages: Allows for easy replacement of the transmitter without disrupting the

process.

4. Side-Mounting with Insulation:

○ Description: If space is limited, mount on the side of the tank while using insulation to

protect against heat.

○ Advantages: Useful in tight spaces while maintaining temperature integrity.

By carefully considering these factors, you can effectively mount high-temperature radar level

transmitters to ensure reliable and accurate performance in demanding environments

Electrical connections

When using the transmitter with 4-20 mA current loop systems, several technical considerations are

essential for effective design, installation, and troubleshooting. Here are the key points to keep in mind:

1. Signal Characteristics

● Current Range: The 4-20 mA range allows for a minimum signal (4 mA) to indicate the lowest

level of measurement and a maximum signal (20 mA) for the highest level. This range helps

distinguish between a valid zero signal and a fault condition (e.g., 0 mA).

● Linearity and noise immunity: The relationship between the sensor output and the current

signal should be linear for accurate measurements. Ensure that the transmitter is calibrated

correctly to produce a linear output and at the same time there is a high level of noise immunity.

2. Power Supply

● Voltage Requirements: Ensure the power supply voltage is adequate for the transmitter and any

additional components in the loop. Voltage must be in the 12-36 VDC range.

● Loop Resistance: Calculate the total resistance in the loop, including the transmitter, wiring, and

any load devices. The loop resistance should not exceed the power supply voltage divided by 20

mA (Ohm’s Law).

3. Wiring and Installation

● Cable Type: Use twisted-pair cables to minimize electromagnetic interference (EMI) and noise.

Shielded cables are also recommended in noisy environments.

Note: Cable outer diameter: Ø6…12 mm (Ø.24… Ø.47") (shielded cable is recommended), wire

cross section: 0.5…1.5 mm2 (AWG20…AWG15)

● Distance Considerations: The maximum distance for a 4-20 mA loop is generally around 1,000

feet (300 meters), but this can vary based on wire gauge and environmental conditions.

Always verify the maximum distance based on the specific application.

● Connection Polarity: Ensure correct polarity in the connections, incorrect polarity can lead to

misinterpretation of data.

4. Grounding and Shielding

● Common Ground: Use a common ground point for all components in the system to avoid

ground loops, which can introduce noise and errors.

● Shielding: Properly ground and shield cables to protect against external interference, especially

in industrial environments

80 GHZ RADAR LEVEL TRANSMITTER BRLT001

5. Device Compatibility

● Input Impedance: Ensure that the receiving device (e.g., PLC, DCS, or indicator) has an

appropriate input impedance to avoid loading the current loop, which could affect accuracy.

● Signal Conditioning: If necessary, use signal conditioning devices to convert the 4-20 mA signal

into other formats or to isolate devices.

6. Fault Detection

● Signal Monitoring: Incorporate diagnostic features to monitor the current loop for fault

conditions (e.g., open circuit, short circuit, or over-range) and provide alerts.

● Calibration: Regularly calibrate the system to ensure ongoing accuracy. Use calibrated test

equipment to validate the 4-20 mA output under various conditions

Technical Specifications

Output

Two-wire 4-20ma current loop

Measuring range

10 m, 30 m, Higher range optional

Resolution

1mm

Repeatability

1mm

Accuracy(2 sigma)

±2 mm

Power supply

12VDC~36VDC

Ambient temperature and humidity

-20℃～+70℃（0%～95%）RH

Antenna Lens

PTFE, PEEK optional

Frequency Span

77GHz-81GHz

Electrical connector

M20×1.5（F）/1/2NPT

Process connection

G2/M68x2

Explosion-proof standard

ExdiaⅡCT6 GB

Protection rating

IP67

Wide Applications

Suitable for various applications from simple cylindrical tanks to complex tanks with difficult

geometry or tanks with internal obstacles.

Dimensions

Diameterϕ98mm×Height223mm

Weight

1.23kg

Note: Specification and selection of special product materials, options, and/or components must be

made by the purchaser of the equipment