Endress+Hauser FMR20B Micropilot Radar with Fixed Cable

FMR20B compact radar level sensor with fixed cable

The Endress+Hauser FMR20B is a compact 80 GHz Micropilot radar for continuous level measurement in liquids and bulk solids, and for flow measurement in open channels and weirs. It is a two-wire, loop-powered transmitter with 4 to 20 mA and HART, and it comes with a permanently attached connecting cable instead of a terminal housing. A small LED on the housing shows the device status at a glance, and Bluetooth is available as an option for setup from a phone.

The FMR20B is built from PVDF and PBT/PC with an EPDM seal, a combination chosen for water, wastewater and utility duty. Its maximum range is 30 m, its accuracy is up to ±2 mm in liquids, and the process envelope is –40 to +80 °C at –1 to 3 bar. A near twin, the FMR30B, uses the same measuring technology in a housing with a local display and a cable gland instead of a fixed cable.

FMR20B technical specifications

How the FMR20B works and what it needs to see

The FMR20B is a downward-looking frequency-modulated continuous wave radar. It sweeps its 80 GHz signal, compares the transmitted and returned frequency and derives the distance to the surface, then calculates level from the empty distance you enter. Because the principle does not depend on density, temperature of the medium or vapour in the vessel, the same device works in water pits, chemical day tanks and silos with fine powders.

The datasheet divides liquids into four media groups by relative permittivity, from group A (1.4 to 1.9, such as liquefied gas) to group D (above 10, such as aqueous solutions). The achievable range depends on the group and on surface turbulence. For example, the 80 mm antenna reaches 30 m in a calm storage vessel with group C or D media but 23 m for group B media, and in an agitated vessel the 80 mm range for group B drops to 7 m. If the permittivity is unknown, assume group B.

FMR20B open-channel flow and linearisation

The FMR20B includes preprogrammed volume tables for pyramid, conical and angled bottoms, horizontal cylinders and spheres, plus up to 32 manual points. For open channels it adds flow linearisation for Khafagi Venturi, Venturi, Parshall, Palmer-Bowlus and ISO 4359 trapezoidal, rectangular and U-shaped flumes, and for trapezoidal, rectangular broad-crested, rectangular thin-plate and V-notch weirs. A non-resettable totalizer sums the flow. This makes the FMR20B a single-box solution for irrigation canals, treated-water outfalls and storm-water channels.

FMR20B selection and ordering checklist

• Antenna: 40 mm (G 1-1/2 thread, 20 m) for small tanks and pits, or 80 mm (UNI slip-on flange, 30 m) for longer range and narrower beam.
• Cable length: 5, 10, 15, 20, 30 or 50 m standard, or a custom length up to 300 m; marine-approved units use halogen-free cable.
• Hazardous area approval, if the sensor sits in an Ex zone, and dust-ignition-proof versions.
• Bluetooth option for SmartBlue commissioning, and whether a loop-powered RIA15 remote indicator is wanted.
• Mounting: wall or ceiling bracket, rope mounting, side or top cable entry, UNI flange size.
• Medium permittivity, surface condition and the vessel type (storage, buffer, agitated).

Installing and commissioning the FMR20B

Install the FMR20B so the antenna points straight down, clear of inlet streams and internal structures. The sensor cable is not a supporting cable, so use the supplied bracket or a customer-supplied rope for suspension. The datasheet gives maximum nozzle lengths for both antennas, so check the nozzle diameter before choosing the 40 mm or 80 mm version. Protect the sensor from direct sun with a shade or weather cover; the permitted ambient temperature is up to +80 °C.

On start-up the device needs up to 15 seconds to reach full performance. Connect a 250 ohm HART resistor when the power supply has a low impedance, then use the SmartBlue app or a HART tool to run the commissioning wizard. Heartbeat Verification is available, and the device stores up to 100 event messages that help with fault finding.

FMR20B applications in Oman and the GCC

In Oman and the wider Gulf region the FMR20B is a practical fit for desalination and water-network utilities: lift stations, break tanks, storm-water basins and treated-water reservoirs. It also suits chemical dosing tanks, diesel and utility storage, and open channels at industrial sites. The plastic antenna avoids corrosion from chlorinated and brackish water, the IP68 rating tolerates flooding, and the non-contact principle means no sensor fouling in grease or sludge. Seven Star LLC supplies Endress+Hauser instruments as an independent supplier in Muscat to contractors, utilities and plant operators across the GCC.

FMR20B compared with related Micropilot units

Information to send with an FMR20B RFQ

• Medium, relative permittivity if known, and whether the surface is calm or agitated.
• Maximum and minimum level, tank height, nozzle details or flange size.
• Process temperature and pressure, plus location (indoor, outdoor, flooded pit).
• Cable length, Bluetooth option, hazardous area or marine approval requirement.
• Number of units and whether open-channel flow measurement is needed.

Documents and quotation

The Endress+Hauser Technical Information for the FMR20B HART version is attached on this page as a datasheet, including the media group range tables and the flow linearisation list.

Send the FMR20B order code or your application data, and we will prepare a quotation for delivery in Oman and the GCC.