Accurate level measurement is essential for safe, efficient and reliable industrial operation. In many tanks, reservoirs and process vessels, the measured medium may be corrosive, contaminated, foamy or difficult to access. In such applications, non-contact measurement technology provides an important advantage by eliminating direct contact between the sensor and the process material.
The ELU 804A Ultrasonic Level Transmitter is designed for intelligent, non-contact level measurement in liquid and material level applications. With ultrasonic measuring technology, LCD display, temperature compensation, analog output and optional communication features, ELU 804A provides a practical solution for industrial level monitoring and control.
What Is ELU 804A?
ELU 804A is an ultrasonic level transmitter used for measuring liquid level and material level without contacting the medium. The sensor is installed above the measured surface and determines the level by sending and receiving ultrasonic sound waves.
Because the device does not touch the measured material, it helps eliminate common problems found in traditional level measurement technologies, such as clogging, winding, leakage, corrosion and maintenance difficulties.
This makes ELU 804A suitable for many industrial environments where pressure type, capacitive type or float type measurement methods may not be preferred.
Operating Principle
The ELU 804A works by transmitting an ultrasonic pulse from the sensor toward the surface of the liquid or material. The sound wave is reflected from the surface and received again by the same sensor.
The device calculates the time between sending and receiving the reflected ultrasonic signal. This time is then converted into a distance value. By comparing this distance with the configured mounting height and measurement range, the transmitter determines the current level.
The catalog diagram shows the relationship between mounting height, measurement distance, current level, maximum level and blind spot. This helps users understand the correct installation geometry and measurement limits for reliable operation.
Non-Contact Measurement Advantage
One of the most important advantages of ELU 804A is its non-contact measurement principle. Since the sensor does not physically touch the medium, it reduces wear and avoids contamination-related problems.
This is especially useful for liquids that may be corrosive, dirty, sticky or difficult to measure with mechanical devices. It also simplifies maintenance because there are no moving parts inside the process.
Application Areas
ELU 804A can be used in many industrial sectors related to liquid level measurement and control. The catalog highlights application areas such as electricity, metallurgy and mine industries, petroleum industry, chemical industry, water treatment and paper production.
These sectors often require continuous level measurement in tanks, open basins, storage systems and process vessels. ELU 804A provides a flexible solution for these applications by offering non-contact operation and multiple output options.
Technical Specifications
ELU 804A has a working temperature range of -10 °C to +60 °C. The working pressure is atmospheric.
The frequency range is 20–350 kHz, and the accuracy is specified as ±0.3% to ±0.5%. The response time is less than 1 second, allowing fast level updates for monitoring and control systems.
The device includes temperature compensation, which improves measurement reliability when ambient or process conditions change.
Measurement Range and Blind Area
The ELU 804A is available with measurement ranges of 3 m, 5 m, 8 m, 10 m and 40 m according to the ordering structure.
The inactive area is less than 0.3 m for the 3 m version and less than 0.40 m for the 40 m version. This blind area must be considered during installation to ensure that the maximum level does not enter the sensor’s inactive zone.
The measurement angle is 10° for 3–15 m ranges and 18° for 15–40 m ranges. This information is important when selecting installation position, especially in narrow tanks or vessels with internal obstacles.
Output and Communication Options
The standard output signal of ELU 804A is 4–20 mA two-wire. This makes it easy to connect the transmitter to PLC systems, indicators, controllers and monitoring equipment.
Optional output and communication features include RS485 Modbus, 2 x NPN, 2 x NO/NC relay and 0–10 V. These options allow the device to be adapted for different automation architectures and alarm requirements.
Optional Modbus RS-485 communication is especially useful for digital monitoring and integration into industrial control systems.
Power Supply and Low Power Consumption
ELU 804A supports different power supply options, including 12–24 VDC, 18–32 VDC and 220 VAC depending on configuration.
Power consumption is less than 1.5 W, and for the two-wire version it is less than 0.8 W. This low power requirement makes the device suitable for efficient industrial operation.
Display and Local Adjustment
The transmitter includes a self-illuminated LCD display, allowing users to read measurement values and configure the device directly at the installation point.
The electrical connection section shown in the catalog includes Menu, Step and OK buttons. These buttons support local parameter setting and commissioning.
The device also supports adjustable start and end points of the output range, factory reset function, digital filtering and dynamic echo recognition. These features help improve measurement stability and simplify setup.
Mechanical Design and Materials
The ELU 804A has an ABS plastic housing as standard. The standard connection material is PP, with PTFE and PVDF available as optional materials.
The standard mechanical connection is 2" BSP for the 0–3 m to 15 m range versions with nut. The ordering table also lists mechanical connection options such as M60 x 2 mm, 1 1/2" BSP and 3 1/2" BSP for selected measurement ranges.
The protection class is IP65, making the transmitter suitable for general industrial field conditions.
Advantages of ELU 804A
ELU 804A offers several practical advantages for industrial users. It has no moving parts, which reduces wear and maintenance requirements.
The product is designed with a durable mechanical structure and easy-to-assemble modular design. It is resistant to vibration and provides stable measurement without direct contact with the medium.
The catalog also highlights that the device is not affected by foam or liquid splashes, which can be important in tanks with unstable surfaces or dynamic filling conditions.
Configuration Flexibility
The ordering structure allows users to define the model, certificate, measurement range, mechanical connection, output type, housing material, connection material, electrical connection and optional features.
Available options include 2 x relay, Modbus RS485, 0–10 V three-wire, 2 x NPN relay and special configurations. This flexibility makes ELU 804A adaptable for different process and automation requirements.
Why Choose ELU 804A?
ELU 804A is a strong choice for applications requiring simple, reliable and non-contact level measurement. Its ultrasonic measurement principle eliminates direct contact with the medium and reduces typical maintenance issues found in mechanical or contact-based technologies.
With analog output, optional Modbus communication, LCD display, temperature compensation, dynamic echo recognition and multiple measurement ranges, ELU 804A provides a practical solution for industrial level monitoring.
Conclusion
The ELU 804A Ultrasonic Level Transmitter is an intelligent non-contact level measurement device for liquid and material level applications. With ultrasonic pulse technology, 4–20 mA output, LCD display, temperature compensation, IP65 protection and optional Modbus or relay outputs, it offers a flexible and reliable solution for industrial tanks and process systems.
For industries such as water treatment, chemical processing, petroleum, mining, metallurgy and paper production, ELU 804A helps improve level monitoring, reduce maintenance and support stable automation performance.