Rosemount 3308A Wireless Guided Wave Radar Level Transmitter

Overview

The Rosemount 3308A is the transmitter of the Rosemount 3308 Series, which Emerson describes as the world’s first true wireless guided wave radar, built on field-proven technologies. It gives accurate, direct level and interface measurement that is virtually unaffected by process conditions, and it communicates over IEC 62591 WirelessHART instead of a 4–20 mA cable. The Rosemount 3308A uses a cut-to-fit probe and a self-organising network, so commissioning is fast and the instrument has no wires, no moving parts and no need for recalibration.

Seven Star LLC supplies the Rosemount 3308A to upstream oil and gas operators, gas plants, utilities and industrial users in Oman and the GCC, from our office in Muscat. Wireless guided wave radar is well suited to the dispersed assets common in Oman, such as well-pad tanks, remote separators, produced water pits and sumps, where power and signal cables are long and costly.

Measurement Principle

According to the Emerson data sheet, the Rosemount 3308A is based on Time Domain Reflectometry. Low-power nanosecond pulses are guided along a probe submerged in the process medium. When a pulse reaches the surface, part of the energy is reflected back to the transmitter, and the time difference between the generated and reflected pulse is converted into a distance from which total level or interface level is calculated. A high dielectric constant gives a stronger reflection and longer measuring range.

Because the measurement follows the probe, Emerson notes that it is virtually unaffected by temperature, pressure, vapour gas mixtures, density, turbulence, bubbling or boiling, varying dielectric media, pH and viscosity. As general engineering context, the guided pulse is much less sensitive to tank geometry and nozzle obstructions than free-space radar, and it can see an oil-water interface underneath the upper product, which is why guided wave radar is widely used on separators and settling tanks.

Engineering Design of the Rosemount 3308A

The Rosemount 3308A uses a wireless dual-compartment housing in aluminium or stainless steel, rated IP66/67 and NEMA 4X, and can be ordered as a level and interface transmitter or a level-or-interface transmitter. Probe options include flexible single lead up to 17 m, rigid single lead in 8 mm and 13 mm diameters, a segmented rigid single lead up to 10 m and a coaxial probe up to 6 m, with materials such as 316L, Alloy C-276, Duplex 2205 and PTFE-covered versions. Weights, chucks, long studs and centering discs are available to suit nozzles, chambers and agitated tanks.

Wireless options include an external antenna, an extended-range external antenna and a high-gain remote antenna, each with an adapter for the Black Power Module or the extra-long-life Blue Power Module. The update rate is user-selectable from 4 seconds to 60 minutes. Under reference conditions Emerson gives a power module life of five years for the high performance profile and nine years for the standard profile at a one-minute update rate. Configuration is supported by AMS Device Manager, AMS Device Configurator and AMS Wireless Configurator, and Signal Quality Metrics are available with the diagnostics suite.

Key Features

The Rosemount 3308A product data sheet supports the following features.

• True wireless guided wave radar removes the need for power and signal cables at the measuring point.
• Direct level and interface measurement suits separators, settling tanks and storage tanks.
• High performance profile reference accuracy is 3 mm below 10 m distance and 0.03 % of distance beyond 10 m.
• Flexible single lead probes reach a measuring range of 17 m, with rigid, segmented and coaxial alternatives.
• Standard process ratings reach 150 °C and 52 bar, depending on probe, seal and connection.
• Cut-to-fit probes and a self-organising network make commissioning fast and simple.
• No wires, no moving parts and no recalibration minimise maintenance.
• Power module life of up to nine years at a one-minute update rate keeps site visits to a minimum.

Industrial Applications

Emerson lists storage and buffer tanks for oil, gas condensate, water and chemicals, low-pressure separators with level and interface, waste tanks and sump pits, open ponds, basins and sumps, and chamber or pipe installations as typical applications for the Rosemount 3308A. In the Oman context this includes condensate and crude storage at gathering stations, three-phase separators at well clusters, closed drain drums and produced water tanks, evaporation ponds, and chemical injection tanks on remote platforms where adding a new wired transmitter would require cable trenching across a live plant.

Seven Star LLC supplies the Rosemount 3308A in the Sultanate of Oman and the GCC and can align it with the wired Rosemount radar range already used on many sites, including the Rosemount 3300 guided wave radar level transmitter, the Rosemount 5300 level transmitter for higher performance wired duties, and the Rosemount 702 wireless discrete transmitter that shares the same WirelessHART gateway.

Technical Specifications

The following Rosemount 3308A data is taken from Emerson product data sheet 00813-0100-4308.

How to Order

For a Rosemount 3308A quotation, send Seven Star LLC an RFQ with the medium, required level and interface measurements, probe type and length, process connection, pressure and temperature, and hazardous-area approval. The Emerson product data sheet is available for download on this page. Seven Star LLC supplies Rosemount wireless instruments from Muscat across Oman and the GCC, with sourcing and model selection support for gateway planning and start-up.