Endress+Hauser Levelflex FMP50: Guided Wave Radar for Reliable Liquid Level Measurement

Choosing a level transmitter requires more than checking a measuring range. The process medium, dielectric constant, vessel height, probe type, installation position, process connection, communication protocol and approvals all influence the final FMP50 configuration.

How the Levelflex FMP50 Measures Level

The FMP50 uses guided wave radar, also known as time-of-flight measurement. High-frequency radar pulses travel along a rod or rope probe toward the product surface. The reflected signal returns to the transmitter, and the measured travel time is converted into level.

Because the radar signal is guided by the probe, the measurement remains reliable across many changing process conditions. Endress+Hauser states that measurement is not affected by changing media, temperature changes, gas blankets or vapors.

FMP50 Key Specifications

Specifications depend on the selected product configuration and may be revised by the manufacturer. Always verify the complete order code and current technical documentation before purchase.

Where Is the FMP50 Commonly Used?

The Levelflex FMP50 is a strong choice for straightforward continuous liquid-level duties, including:

• Storage tanks for water and water-based liquids

• Utility and service tanks

• Supply and buffer vessels

• Liquid, paste and slurry measurement within the specified process limits

• Applications with vapor, gas blankets or changing media

• Projects requiring HART, PROFIBUS PA or FOUNDATION Fieldbus integration

The FMP50 is intended for basic applications. More demanding temperature, pressure, corrosion, hygienic or interface-measurement duties may require another Levelflex model and should be evaluated separately.

Rod Probe or Rope Probe?

Rod probe

The rod version provides a rigid measuring element and a maximum published measuring distance of 4 m. It is often practical for smaller vessels where sufficient installation clearance is available and the probe can be positioned away from internal structures.

Rope probe

The rope version extends the maximum published measuring distance to 12 m and is suitable for taller vessels. The probe must be installed and, where required, anchored according to the application and the manufacturer’s instructions.

Probe selection must consider vessel height, nozzle geometry, available headroom, agitation, inlet flow, internal fittings, build-up and the mechanical behavior of the product.

FMP50 Guided Radar vs Free-Space Radar

Guided radar and free-space radar both use electromagnetic waves, but their installation behavior differs.

• FMP50 guided radar: the signal travels along a probe that extends into the vessel.

• Free-space radar: the signal travels through the vessel atmosphere without a probe touching the product.

Guided radar can be useful where the probe provides a defined signal path, while free-space radar may be preferred when contact with the medium or a long internal probe is undesirable. Vessel geometry and process conditions should determine the technology—not the model name alone.

Information Required for Correct FMP50 Selection

Before requesting a quotation, collect the following information:

1. Medium: product name, dielectric constant where known, conductivity and tendency to build up.

2. Process conditions: normal and maximum temperature and pressure.

3. Vessel: total height, measuring range, nozzle dimensions and internal structures.

4. Probe: rod or rope, required length and any anchoring requirement.

5. Connection and materials: thread or flange and compatible wetted materials.

6. Electrical interface: HART, PROFIBUS PA, FOUNDATION Fieldbus or other required option.

7. Approvals: hazardous-area, overfill-prevention, SIL or project-specific certificates.

8. Existing unit: complete order code, serial number and nameplate photo for replacement projects.

Why the Complete Order Code Matters

FMP50 identifies the product family, not the complete instrument. Probe type and length, process connection, housing, electrical output, display, approvals and optional features are defined by the full order code.

For an existing installation, send the complete code exactly as shown on the nameplate—for example, a code beginning with FMP50-...—together with the probe length and application details. This reduces the risk of receiving an instrument that fits the model family but not the actual process.

Technical and trademark notice: Technical data in this article is based on current Endress+Hauser product information and is subject to configuration and revision. Confirm specifications, compatibility, approvals, availability and lead time with the quotation. Product imagery is representative. We are an independent supplier; trademarks belong to their respective owners.

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