VEGA VEGAPULS 21 80 GHz Radar Level Sensor

Overview

The VEGA VEGAPULS 21 is a compact radar sensor for continuous, non-contact level measurement in standard applications across all industrial plants. It belongs to the VEGA basic line of plastic-housed radar instruments and works with 80 GHz W-band technology, which produces a narrow 8° beam from a small antenna. The VEGA VEGAPULS 21 is offered as a two-wire 4–20 mA/HART device, so it drops straight into an existing analogue loop and reports level to a PLC, DCS or telemetry outstation without a separate power cable.

Seven Star LLC supplies the VEGA VEGAPULS 21 to water utilities, chemical dosing contractors and plant operators in Oman and across the GCC, from our office in Muscat. The sensor suits projects where a reliable radar reading is needed at a modest budget: chlorine and coagulant dosing tanks at desalination plants, wet wells at sewage pumping stations, additive tanks in refineries and IBC containers in packaging halls.

Measurement Principle

According to the VEGA specification sheet, the VEGA VEGAPULS 21 emits a continuous radar signal through its antenna, and the frequency of that signal is modulated. The signal is reflected by the surface of the medium and received again by the antenna as an echo. The frequency difference between the emitted and the received signal is proportional to the distance, and therefore depends on the filling height. The electronics convert the calculated filling height into the 4–20 mA output signal and the HART value.

As general engineering background, a high transmit frequency such as 80 GHz focuses the microwave energy into a tight cone. The practical result is that the beam can pass between ladders, pipes and agitator blades in a small vessel and still return a clean echo from the liquid surface. Because nothing touches the product, there is no float to stick, no probe to coat and no wear part to replace, which is why the manufacturer describes the device as maintenance-free. Vapour, temperature changes inside the tank and changing product density do not influence the radar distance measurement in the way they influence hydrostatic or ultrasonic methods.

Engineering Design of the VEGA VEGAPULS 21

The VEGA VEGAPULS 21 has a housing of PBT plastic rated IP66/IP67 to IEC 60529 and Type 4X to UL 50. The wetted parts are made of PVDF and the process seal is FKM, a combination well suited to acids, lyes and treated water. The process fitting is a G1½, 1½ NPT or R1½ thread with a 50 mm hexagon, and the dimensional drawing shows an overall height of 156 mm with a housing diameter of 77.5 mm. The cable outlet is lateral, which allows the sensor to be hung from a mounting strap or bracket above an open channel or basin.

The VEGA VEGAPULS 21 has no local display; it is a blind transmitter intended for integration into a control system. Adjustment is carried out over the signal cable with the VEGACONNECT interface adapter and PACTware with the matching DTM, through a HART Communicator or asset tools such as AMS or PDM, or wirelessly. The Bluetooth version connects to smartphones and tablets running iOS or Android and to Windows PCs, with a typical range of 25 m, so a technician can commission a sensor mounted on a tank roof from the ground. The operating voltage is 12 to 35 V DC.

Key Features

The main features of the VEGA VEGAPULS 21, taken from the VEGA specification sheet, are listed below.

• Non-contact 80 GHz radar technology gives maintenance-free operation with no moving or wetted mechanical parts.
• Measuring range up to 20 m covers most storage tanks, sumps, channels and small bulk solids silos.
• Deviation of 2 mm or better gives level data that is suitable for inventory and dosing control.
• A beam angle of 8° keeps the microwave cone away from tank walls and internal structures.
• The two-wire 4–20 mA/HART output connects directly to standard analogue inputs and HART hosts.
• PVDF wetted parts with an FKM seal resist acids, lyes and many aggressive additives.
• Bluetooth 5.0 adjustment through a free app allows wireless setup from a safe distance.
• The PBT housing is rated IP66/IP67 and Type 4X for outdoor installation in harsh weather.

Industrial Applications

VEGA names water treatment, storage tanks with acids and lyes, additives in all industrial areas and level measurement through a plastic tank or IBC container as typical uses for the VEGA VEGAPULS 21. In Oman these duties appear at reverse osmosis desalination plants on the Batinah coast, at municipal wastewater treatment works, in the dosing skids of oil and gas facilities and in the chemical stores of manufacturing plants in the Sohar and Rusayl industrial estates. The sensor can also measure through the wall of a non-metallic tank, which avoids drilling a new opening in an existing plastic vessel.

The VEGA VEGAPULS 21 is suitable for liquids and for small bulk solids silos or containers, so food, feed and building-material plants in the Salalah Free Zone can use it for small hoppers as well. Seven Star LLC supplies the VEGA VEGAPULS 21 to these sectors in the Sultanate of Oman and the wider GCC and can match it with VEGA instruments already on site, such as the VEGA VEGAPULS 6X radar level transmitter for demanding process vessels, the VEGA VEGAPULS C21 compact radar sensor with a fixed cable, or the VEGA VEGAPOINT 21 capacitive point level switch for high-level alarms.

Technical Specifications

The table below summarises the VEGA VEGAPULS 21 data published in the VEGA specification sheet 58363-EN.

How to Order

To order the VEGA VEGAPULS 21, send Seven Star LLC a formal RFQ with the medium, tank height, process fitting and any hazardous-area approval you need, and our instrumentation team will confirm the correct order code. The VEGA specification sheet is available from the download section of this page. Seven Star LLC supplies VEGA level instruments from Muscat to customers throughout Oman and the GCC, with sourcing and model selection support.