64-80GHz FMCW Level Radar is a radar sensor for continuous level measurement of liquids. Sino-Inst also launched a radar level sensor operating at 76-81 GHz.
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 76-81GHz FMCW Level Radar
The LM78xx series is an FMCW radar operating at 76-81 GHz, which has a maximum measuring range of 120m and a minimum blind zone of 8cm. It supports 4-wire and 2-wire applications. Higher operating frequency and shorter wavelengths make it ideal for solid applications, including those with extreme dust and high temperature to + 200℃.
The radar consists of an electronic circuit coupled to a lens antenna and flange for quick and easy positioning.
The main benefits of using 78 GHz over devices using lower frequency are:
- Based on the self-developed CMOS millimeter wave RF chip, a more compact RF architecture, a higher signal-to-noise ratio, and a smaller blind zone are realized.
- 5GHz working bandwidth means higher measurement resolution and accuracy.
- 3°antenna beam angle, so the interference in the environment has less impact on the instrument, and the installation is more convenient.
- Shorter wavelength yields good reflection properties on sloped solids, so aiming towards material angle of repose is usually not necessary.
- Support remote debugging and remote upgrading to reduce the cost of field personnel.
Communication and Programming
LM78XX supports 485 bus protocol (4-wire), serial-port (2-wire) protocol, and hart (2-wire) protocol. It is very easy to install and configure via an optional graphical local display interface on a PC. Or you can modify the built-in parameters either locally via the pushbuttons. Or you can use a cell phone to control LM78xx via Bluetooth.
Extended Reading: Case: High Temperature Radar Level Transmitter for Melted Salt-Solar Photovoltaic Power Station
Specifications of 76-81GHz FMCW Level Radar
| Frequency | 76GHz ~ 81GHz, 5GHz FMCW bandwidth |
| Measuring range | LM78x0: 0.3 m ~ 60m LM78x1: 0.08m~30m LM78x2: 0.6m ~ 120m |
| Measurement accuracy | ±1mm |
| Beam angle | 3°/8° |
| Minimum measured dielectric constant | >=2 |
| Power | 15~28VDC |
| Communication | LM782x: MODBUS LM783x: HART/Series |
| Signal output | LM782x: 4 ~ 20mA or RS-485 LM783x: 4~20mA |
| Fault output | 3.8mA, 4mA, 20mA, 21mA, hold |
| Field operation / programming | 128 × 64 dot matrix display / 4 buttons PC software Bluetooth |
| humidity | ≤95%RH |
| Enclosure | Aluminum alloy, stainless steel |
| Antenna type | Lens antenna/anti-corrosive antenna/flange isolated by quartz |
| Process temperature | T0:-40~85℃; T1:-40~200℃; T2:-40~500℃; T3:-40~1000℃ |
| Process pressure | -0.1~2MPa |
| Product Size | Ø100*270mm |
| Cable entry | M20*1.5 |
| Recommended cables | AWG18 or 0.75mm² |
| Protection class | IP67 |
| Explosion-proof grade | ExdiaIICT6 |
| Installation method | Thread or flange |
| Weight | 2.480Kg/2.995Kg |
| Packing box size | 370*270*180mm |
Extended reading: FMCW Radar Level Transmitter 120GHz
64-80GHz FMCW Level Radar Applications
Application area:
Special advantages are the small process fittings for small tanks or tight spaces. The very good signal focusing allows use in vessels with many internal installations.
LM78 series FMCW Level Radar Applications
It is suitable for large range, high dust, steam condensation, mixing, narrow installation space, and occasions with high precision and blind zone requirements.
Applicable working conditions:
- Intermediate silo
- Warehouse
- hopper
- Storage tank
- Process tank
- Mixing tank
Extended Reading: Influence of Dielectric Constant on Liquid Level Measurement | Radar-Guided Wave Radar Level Meter
The influence of high frequency and low frequency of radar liquid level sensor on measurement
- The influence of frequency on measurement
The radar level sensor emits electromagnetic waves through an antenna, and the higher the frequency of the electromagnetic waves. The higher the energy of the electromagnetic wave and the shorter the wavelength, the more obvious the scattering phenomenon. Conversely, the lower the energy, the longer the wavelength, and the energy is not easily absorbed by the gas phase layer.
For an antenna of the same size, a level gauge with a wavelength of 1.2 cm and a frequency of 26 GHz has 6 times higher gain than a level gauge with a wavelength of 3 cm and a frequency of 10 GHz. (Note: Antenna gain is a parameter indicating the degree of concentration of directional antenna radiation).
The received signal diagrams of different frequencies (26-10-6 GHz), the same antenna, dielectric constant, and distance increase are as follows:
The total beam width of the radar level sensor is inversely proportional to the frequency of the device.
Therefore, for an antenna with the same diameter, if the frequency of the radar level sensor 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.
As shown in the picture (the left side is 6 GHz, the right side is 26 GHz).
At the same time, the measurement range of the radar liquid level sensor is also affected by factors such as frequency, antenna size, the dielectric constant of the liquid, and process conditions.
- The application difference between high frequency and low frequency of radar liquid level sensor
When measuring steam, foam, and condensate, choose low-frequency radar first. In most other applications, choose high-frequency radar first for ease of installation.
1) The lower frequency reduces the sensitivity to steam, foam, and antenna contamination. The wave velocity angle of low-frequency radar is wider. It can better deal with the problems of steam, dust, condensation, pollution, and turbulent surfaces.
2) The higher frequency can minimize the impact on the nozzle, tank wall, and interference.
Extended reading: Drop Antenna Radar Tank Level Sensor
Application of 80G radar level sensor in liquid level measurement with stirring and strong steam
The micro-powder business department of a chemical plant has a variety of tanks, with a field measuring a range of 25 meters. There is a stirrer and heating device inside, and there is high steam when feeding.
As shown in the figure below, when the staff opened the observation cover, strong steam could be seen coming out.
A guided wave radar level gauge is selected before the scene. However, guided wave radar is easily affected by factors such as the corrosiveness of the measuring medium and the viscosity of the medium, and the measurement effect is not good.
Extended reading: guided wave radar level sensor advantages and disadvantages
Later, the customer chose the 80G radar level meter, and the historical trend chart after use is as follows. It can be seen that the liquid level of the four 80G radar level gauges installed on-site can be measured well in several loading and unloading processes.
Extended Reading: FMCW Radar for High Temperature Level Sensor
Why do we have to choose an 80G millimeter-wave radar level gauge for liquid level measurement under high steam and stirring conditions? Can the 26G radar level gauge measure?
Explain briefly. The 80G radar level gauge has a high transmission frequency, has good penetration, and is not affected by steam.
The launch angle of 3° can effectively avoid the interference of the stirring blade;
The unique echo tracking algorithm (echo locking function) avoids reading multiple echoes when the material level is high.
However, when the 26G radar level gauge is in a high-steam environment, the radar wave cannot penetrate the steam or the echo is greatly weakened after the radar wave reaches the interface of the medium, and the measurement is unstable;
In addition, the launch angle of the 26G radar level gauge is generally above 20°, so that the radar wave is easily affected by the stirring blade, causing false alarms;
And when the material level is high, there is no internal steam and the range is large, the echo is very strong, and it is easy to read multiple echoes.
Therefore, the 80G radar level gauge can be selected to obtain a good measurement effect for liquid level measurement under high steam and stirring conditions.
Extended reading: Radar Level Meter for Corrosive Liquids
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More Featured Non-Contacting Radar Level Measurement
Sino-Inst offers Alternative to 64-80GHz FMCW Level Radars for level measurement.
A wide variety of 64-80GHz FMCW Level Radars 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.
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Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.