ELW 801 Radar Level Transmitter: Non-Contact Level Measurement for Liquids, Solids and Aggressive Media

Reliable level measurement is one of the most important requirements in industrial process control. Tanks, silos, storage vessels and process systems often contain liquids, solid particulate materials or aggressive fluids under challenging conditions such as dust, vapor, foam, condensation, pressure and temperature variation.

The ELW 801 Radar Level Transmitter is designed to provide accurate and stable non-contact level measurement in these applications. As part of the ELW 800 radar level transmitter series, ELW 801 uses high-frequency radar technology to measure the level of liquids and solid materials without touching the process medium.

What Is ELW 801?

ELW 801 is a radar type level transmitter used for continuous level measurement. It is suitable for liquids, solid particulate materials and aggressive liquids.

The device sends electromagnetic waves from its antenna toward the surface of the measured material. The material surface reflects these waves back to the antenna, and the transmitter calculates the level according to the travel time of the signal.

Because the measurement is non-contact, ELW 801 is suitable for applications where mechanical contact with the medium is not preferred.

Operating Principle

ELW 801 operates by transmitting electromagnetic radar waves from the antenna to the surface of the liquid or solid material. The surface reflects the signal back to the device.

The transmitter calculates the time between the outgoing and returning waves. By comparing this signal travel time with the configured tank or vessel height, the device calculates the current level.

The ELW 800 series uses two microprocessors and a wave-tracking algorithm. This provides strong signal processing capability and supports reliable measurement in demanding process conditions.

Non-Contact Measurement Advantage

One of the most important advantages of ELW 801 is non-contact measurement. Since the sensor does not touch the medium, there is no mechanical wear caused by process contact.

This is especially useful in applications involving sticky materials, condensate formation, aggressive liquids, foam, vapor or dust. According to the catalog, the ELW 800 series is not affected by foam and vapor and is suitable for dusty environments.

This makes ELW 801 a practical solution for tanks and vessels where conventional contact-based level measurement technologies may require frequent maintenance.

Application Areas

ELW 801 can be used in easy operating conditions for level measurement in liquids and solids, especially in abrasive fluids.

Typical application areas include chemical industry, pharmaceutical industry, cooling water tanks, food and plastic industries, power plants, oil plants, cement factories, petroleum tanks, fire water tanks, rivers, waste material applications and wastewater systems.

This wide application range makes ELW 801 suitable for both process automation and storage tank monitoring.

Technical Features

ELW 801 belongs to the ELW 801 / ELW 802 group in the catalog. The measuring range is up to 30 m.

The accuracy is listed as ±2 mm, with ±1 mm repeatability and 1 mm resolution. The response time is less than 2 seconds.

The radar frequency is 76–81 GHz, and the dielectric constant is minimum 1.4, selectable in five different ranges.

The adjustment menu language is English, and the device includes an LCD display for local indication and configuration.

Output and Communication

ELW 801 uses 15–36 VDC two-wire power supply and consumes less than 0.5 W.

The standard output signal is 4–20 mA two-wire + HART, with 1.6 µA resolution. Error signal values can be adjusted as 20.5 mA, 22 mA or 3.9 mA.

The integration time is programmable from 0 to 20 seconds, allowing the user to adapt signal damping according to process conditions.

HART communication can be used with a handheld calibrator and a 250 Ω resistor in the loop, as shown in the catalog wiring diagram.

Mechanical Design

ELW 801 is available with threaded process connection options. The dimension table shows R 1½ and R 3 connection options.

For ELW 801, the catalog lists 230 mm length. The antenna diameter is Ø39 mm for the R 1½ version with 7° beam angle, and Ø70 mm for the R 3 version with 3° beam angle.

The standard process connection is G 1½, with additional options such as G 3, DN50 and DN80 flanged versions within the ELW 800 family.

Materials

The antenna type is listed as flange lens, and the antenna material is PTFE.

The standard housing material is aluminum injection AlSi2Fe, black RAL9005. A plastic housing option is also available.

Connection material options include PTFE, 304 stainless steel and 316 stainless steel. These material options allow the transmitter to be selected according to the process medium and installation requirements.

Process and Environmental Conditions

For ELW 801 / 802 models, the working temperature range is listed as -40 °C to +85 °C. Ambient temperature is -20 °C to +60 °C, and relative humidity is below 95%.

The working pressure range is -0.8 bar to +3 bar.

The protection class is IP66 according to EN60529, making ELW 801 suitable for industrial field installation.

Display and Local Configuration

ELW 801 includes an LCD display and adjustment keys. The catalog shows four local keys:

ESC for back
Up key for previous movement
Down key for next movement
OK for enter / confirmation

This local user interface helps technicians configure the device directly at the installation point.

Measurement Geometry

The catalog explains important level measurement terms such as minimum dead zone, maximum dead zone, maximum level / minimum measurement distance, minimum level / maximum measurement distance and reference plane.

These installation parameters are important for correct setup. They define the measurement range and help ensure that the device is mounted at the correct position relative to the maximum and minimum level points.

Electrical Connection

The electrical connection is made through terminal connection. The cable entry is M20 x 1.5 mm.

The catalog shows a two-wire 4–20 mA connection layout with positive and negative terminals. It also shows grounding details and the use of HART communication through the signal loop.

Correct wiring is important for stable analog output and reliable communication.

Housing Options

The ELW series housing options include B21x aluminum housing and B20p plastic housing.

The B21x aluminum housing has IP66 protection, a temperature range of -40 °C to +200 °C and dimensions of 140 x 104 mm. The B20p plastic housing has IP66 protection, a temperature range of -40 °C to +150 °C and dimensions of 132 x 104 mm.

The housing includes cable gland, plug, grounding terminal and product label areas.

Accessories

The catalog includes useful accessories for field applications. A 304 stainless steel protection sleeve is available for protecting the transmitter against external environmental conditions. It is welded, hinged and openable / closable.

A cooling apparatus made from 304 stainless steel is also available and can be applied to all models for process temperatures up to 250 °C.

These accessories help adapt ELW 801 to more demanding outdoor or high-temperature installations.

Ordering Flexibility

The ordering structure allows selection of model, certificate, connection type, measuring range, working temperature, connection size, output, housing, connection and antenna material, electrical connection and optional accessories.

For ELW 801, the example ordering code in the catalog is based on a 30 m measuring range, 4–20 mA two-wire HART output and R 1½ connection.

Optional accessories include protection sleeve, cooling apparatus and special configurations.

Why Choose ELW 801?

ELW 801 is a strong choice for users who need accurate and maintenance-friendly continuous level measurement. Its non-contact radar principle reduces mechanical wear and helps avoid problems caused by sticky media, foam, vapor, condensation and dust.

With 76–81 GHz radar frequency, ±2 mm accuracy, 4–20 mA + HART output, LCD display, IP66 protection and multiple connection options, ELW 801 provides a reliable radar level measurement solution for many industrial applications.

Conclusion

The ELW 801 Radar Level Transmitter is a non-contact continuous level measurement device for liquids, solid particulate materials and aggressive liquids. It combines high-frequency radar technology, strong signal processing, LCD configuration, HART communication and robust industrial housing design.

For chemical plants, food and plastic industries, cooling water tanks, power plants, petroleum tanks, cement factories, fire water tanks, wastewater systems and other industrial applications, ELW 801 provides stable and reliable level measurement without direct contact with the process medium.