Radar and Guided Wave Radar Level Transmitter are often used in tank level measurement. Radar Level Transmitter and Guided Wave Radar Level Transmitter both use the principle that electromagnetic waves will be reflected on the surface of the medium to measure the level.
For tanks that are tall, have a large measuring range, use clean media, and have ample installation space, non-contact radar level transmitters are more advantageous. If the container has many internal components, the dielectric constant of the medium is low, and the liquid level fluctuates significantly, guided wave radar level transmitters are usually more likely to obtain stable echoes.
Next, let’s look in detail at the differences between radar level transmitters and guided wave radar level transmitters.
First of all, you can learn about the detailed technical parameters, advantages and disadvantages, working principles, etc. of radar level transmitters and guided wave radar level transmitters from our product page.
| Item | Non-contact radar | Guided wave radar |
| Sino-Inst frequency | 26 GHz (RD900), 80 GHz (FMW) | 500 MHz–1.8 GHz (701–705) |
| Contact with medium | No | Yes |
| Max range | 150 m (FMW13, FMW21) | 30 m (701, 703) |
| Accuracy | ±2 mm (FMW11/12/13) | ±5 mm (704), ±10 mm (701/702/703/705) |
| Top blind zone | 8–10 cm (80 GHz) | Depends on probe, plus bottom dead zone |
| Max temperature | 280 ℃ (FMW13G) | 400 ℃ (705) |
| Max pressure | 2.5 MPa (FMW13G/14/15); 4.0 MPa (RD902) | 40 MPa (705) |
| Low dielectric | 80 GHz better than 26 GHz | Works above εr 1.6; 704 coaxial for deionized water |
| Corrosive | PTFE lens (FMW), RD901 | 702 fully PTFE-sealed, up to 20 m |
| Output | 4–20 mA/HART, RS485/Modbus | 4–20 mA/HART |
| Ex rating | Ex ia IIC T6 Ga | Ex ia IIC T6 Ga / Ex d IIC T6 Gb |
Radar Level Transmitter is non-contact, and Guided Wave Radar Level Transmitter is contact.
In other words, GWR cannot be used in situations where food-grade requirements are higher.
Guided Wave Radar Level Transmitter needs to consider the corrosiveness and adhesion of the medium, and it is more difficult to install and maintain a guided wave radar that is too long.
Regarding different media situations, I think “Doug Anderson VEGA Controls Ltd” summarized it very well. It’s available for everyone’s reference. Here we quote it:
| Product/process requirements | Non-contact Radar | Guided Radar (TDR) |
| Abrasive product | 1 | 0 |
| Adhesive product | 1 | 0 |
| Aggressive product | 1 | 0 |
| Agitated process/Viscous product | 1 | 0 |
| Extreme Product/Process temperatures | 1 | 0 |
| Heavy Condensation/Steam | 0 | 1 |
| High process Pressures | 1 | 1 |
| Low product reflectivity/dielectric constant <1.4 | 0 | 1 |
| Interface measurement (i.e.oil/water) | 0 | 1 |
| Narrow vessel | 0 | 1 |
| Obstructions in vessel | 1 | 1 |
| Standpipe/Bridle/Stilling tube | 0 | 1 |
| Foam on surface | 0 | 1 |
| Mounting/Nozzle interference | 1 | 0 |
| Overfill | 0 | 1 |
| Adaptability of a device | 1 | 0 |
| Ease of installation in application/maintenance | 1 | 0 |
| Mechanical fitting size | 0 | 1 |
| 10 | 10 |
Common Radar Level Transmitter can be used interchangeably.
The Guided Wave Radar Level Transmitter generally cannot be used interchangeably because the length of the waveguide rod (cable) is fixed according to the original working conditions. Affected by this, the selection of guided wave radar is more troublesome than that of ordinary radar.
Ordinary Radar Level Transmitter is commonly used on tanks of 30 and 40 meters, and can even measure up to 150 meters.
The guided wave radar Level Transmitter can measure up to 30m.
Guided Wave Radar Level Transmitter also needs to consider the force of the waveguide rod (cable). Due to the force, the measurement distance of guided wave radar is generally not very long.
However, in some special working conditions, the Guided Wave Radar Level Transmitter has obvious advantages. For example, there is stirring in the tank and the medium fluctuates greatly. In such working conditions, the measured value of the guided wave radar with a fixed bottom is more stable than that of the flexible radar.
There is also material level measurement in small tanks. Due to the small installation and measurement space (or there are many interference objects in the tank), ordinary Radar Level Transmitter is not suitable. At this time, the advantages of guided wave radar appear.
In order to better choose suitable liquid level measurement equipment, it is best for us to understand the Difference Between Radar and guided wave radar level transmitters in advance, as well as their installation, maintenance and other requirements.
We, Sino-Inst, are a professional manufacturer of radar level transmitters and guided wave radar level transmitters. We produce 26 GHz and 80 GHz radar level transmitters and guided wave radar level transmitters in various probe rod forms. If you have any questions about the Difference Between Radar and guided wave radar level transmitters, please feel free to contact us!
Zhang Wei, possesses 20 years of experience as an automation instrumentation engineer, specializing in the research, design, installation, commissioning, and maintenance of automation instruments.
Face to various instrument communication protocols (such as Modbus, Profibus, etc.), with solid hardware circuit design and software programming skills (proficient in C language and PLC programming). Has extensive project experience; projects he has led and participated in have all achieved outstanding results, improving product accuracy, reducing costs, and increasing production efficiency.
Possesses excellent communication and coordination skills and a strong team spirit, enabling him to quickly respond to customer needs and provide high-quality automation instrumentation solutions.
