80 GHz Radar Level Meter Retrofit: Tank Survey and RFQ Guide

An 80 GHz radar level meter can provide a narrow beam and compact antenna for many tank retrofits, but frequency alone does not guarantee a successful replacement. The existing nozzle, mounting height, tank roof, internals, product dielectric response, vapour, foam, condensation, pressure and temperature determine whether the new radar can see a stable surface. A retrofit must also preserve the measurement datum, control-system scaling, alarm logic and hazardous-area compliance. Begin with a physical survey and the old instrument configuration, then issue one RFQ that defines both the sensor and the work needed to install, configure and accept it.

Survey the existing tank and nozzle

Measure tank height, nozzle diameter and length, flange or thread, antenna clearance and the distance from reference plane to zero and full points. Photograph weld intrusions and reducers.

Map ladders, coils, agitators, inlets, stilling wells and wall features. A narrow beam helps avoid obstructions only when mounting and aiming are correct.

Document product and operating conditions

State liquid or solid, dielectric behavior, temperature, pressure, vapour, foam, dust, buildup and agitation. Include startup, cleaning, empty-tank and abnormal states.

Provide minimum and maximum level, required blocking distance, response time and accuracy. Identify whether the reading supports inventory, control or overfill protection.

Check the radar and antenna choice

Confirm FMCW range, antenna style, beam angle, process seal, materials and pressure rating. Review condensation and buildup management at the selected mounting point.

Use an echo assessment when geometry is difficult. Do not select 80 GHz only because it is newer than the old technology; verify measurable signal margin and false-echo separation.

Preserve electrical and safety requirements

Record supply voltage, two- or four-wire loop, 4–20 mA, HART or digital protocol, cable, glands, barriers and surge protection. Verify hazardous-area certificates and exact model marking.

Confirm loop resistance and PLC input scaling. Define fault current, lost-echo behavior and how invalid data appears to operators.

Plan configuration migration

Archive the old range, damping, alarm thresholds, linearization, false-echo map and output settings. Translate them to the new reference plane rather than copying numbers blindly.

Review alarm setpoints against the vessel datum. Where independent overfill protection is required, keep it separate from the control transmitter and shared failure paths.

Commission with recorded evidence

Capture an empty or known-level echo curve, verify distance and level at representative points and compare the PLC value in engineering units. Test filling and emptying response.

Record final configuration, echo quality, false echoes, loop current, alarms and as-left drawings. Revalidate after nozzle or internal changes.

Resolve retrofit deviations before purchase

Create a deviation list for nozzle modification, flange adapter, cable replacement, barrier change, display units and control-system work. Identify who supplies and installs every item and whether a shutdown is required.

Ask the supplier to confirm the proposed model against the final survey, not an early generic datasheet. Freeze the accepted reference dimensions and alarm basis so commercial changes cannot silently alter the measurement scope.

Engineering checklist

Measure the nozzle and reference datum.
Map tank internals and process conditions.
Verify antenna, range and signal margin.
Confirm wiring, approvals and fault current.
Migrate settings against the same datum.
Accept with echo and loop records.

Frequently asked questions

Will 80 GHz work through any nozzle?

No. Nozzle length, diameter, welds, alignment and antenna position can still distort or block the signal.

Can the old range be copied?

Only after confirming the new reference plane and scaling; identical numbers may represent different elevations.

What should an RFQ include?

Include tank and nozzle drawings, product conditions, range, interfaces, approvals, existing configuration and acceptance needs.

Need a project-specific review? Send process data, drawings, photographs and acceptance criteria through our contact page.