Continuous measurement, local indication and point level detection

Level

Selection starts with the process, not just the range: liquid or solid, pressure and temperature, vapour, foam, agitators, internals, dielectric constant, density, interface measurement and access to the measurement point.

Level transmitters

80 GHz radar, GWR, ultrasonic, laser and magnetostrictive instruments for continuous measurement.

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Level indicators

KM26, LMG200 and bypass systems: local indication independent of power, with options to add a transmitter and switches.

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Level switches

Float, displacer, vibrating, capacitive and magnetic switches for low/high level, overflow and pump protection.

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Practical guidance

Which technology should you consider first?

Initial guidance: final selection must be checked against the process specification.

Application	First technology to consider	Why
Liquid tank, non-contact measurement	80 GHz radar	Narrow beam, no fluid contact, good tolerance of pressure, temperature and vapour.
Water / wastewater, tanks and wet wells	Ultrasonic	Simple, cost-effective solution, particularly suitable for multiple installations.
Interface or demanding process	GWR	Energy is guided along the probe; useful with vapour, moderate foam and bypass chambers.
Bulk solids / long distances / narrow beam	Laser or radar	Reduces interference from internal structures; laser requires a clear optical path.
Very high accuracy on liquids / interfaces	Magnetostrictive	Measures float position with high precision; well suited to KM26/chamber installations.
High/low threshold	Level switch	Simpler than a continuous transmitter when only a contact is required.

Hydrostatic / DP level

For level derived from hydrostatic pressure, pressurised tanks or wet/dry legs, see the Pressure section.

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Best to know

Three common level measurement mistakes

Selecting by range alone

Foam, vapour, density, dielectric constant, agitators and nozzles often matter more than the measuring distance.

Ignoring geometry

Nozzles, ladders, coils, beams and filling streams can create false echoes or obstruct float movement.

Overlooking maintenance

Access, isolation valves, drains/vents and probe withdrawal must be planned before purchase.

FAQ

Frequently asked questions about level measurement

Which level technology is the most universal?

There is no universal technology. Non-contact radar is versatile, but GWR, ultrasonic, laser, magnetostrictive and hydrostatic pressure may be better for specific applications.

Radar or ultrasonic for water?

Ultrasonic is often the lower-cost solution for tanks and wastewater; radar becomes attractive where vapour, condensation, temperature, pressure or obstacles make ultrasonic measurement less predictable.

How do I measure the interface between two liquids?

Common solutions are GWR and magnetostrictive measurement, provided fluid properties and installation geometry allow reliable separation of the two levels.

Can I measure level with a pressure transmitter?

Yes. Gauge/hydrostatic pressure can be used in open tanks; closed or pressurised vessels often use differential pressure, with or without diaphragm seals.