Rosemount 5408 Non-Contacting Radar Level Transmitter

The Rosemount 5408 is a two-wire, non-contacting radar level transmitter from Emerson that uses Frequency Modulated Continuous Wave (FMCW) technology. Instead of the short pulses used by traditional pulse radars, the 5408 emits a continuous, frequency-swept microwave signal in the 24.05–27.0 GHz band and, together with Smart Echo Supervision, maximises radar signal strength for a far more robust and reliable echo — even on difficult surfaces with foam, turbulence, condensation or antenna build-up.

Measurement is unaffected by density, viscosity, temperature, pressure or pH. Standard reference accuracy is ±0.08 in. (±2 mm), with an ultra-accuracy option of ±0.04 in. (±1 mm), and repeatability of ±0.04 in. (±1 mm). The standard Rosemount 5408 reaches up to 492 ft (150 m), while the safety-rated 5408:SIS covers up to 130 ft (40 m).

This particular unit is configured with a 316/316L (EN 1.4404) cone antenna on a 4-in./DN100 ASME B16.5 Class 150 weld-neck flange (flange stamped F316/F316L / 1.4404), an aluminium dual-compartment housing and an M5 LCD display. The electronics deliver a two-wire 4–20 mA signal with HART (device revision 1, HART protocol 7) on 12–42.4 Vdc, and the transmitter stays self-powered for up to two seconds to ride through cable glitches or lightning.

The nameplate certifies IECEx flameproof protection — Ex db IIC T6…T2 Ga/Gb and Ex tb IIIC T85 °C…T250 °C Db — under IECEx FMG15.0033X, with an ambient rating of -60 °C ≤ Ta ≤ +70 °C, IP6X ingress protection and FCC ID K8C5408T. Ingress protection for the family is IP66/67/68 and NEMA 4X. A Smart Diagnostics Suite gives early warning of build-up, weak supply or abnormal surface conditions and keeps the last seven days of measurements, alerts and echo profiles in local memory.

For safety-instrumented overfill prevention the Rosemount 5408:SIS variant is certified to IEC 61508 for SIL 2 and supports remote proof testing without process interruption.