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Brand: Endress+Hauser (E & H)
Endress+Hauser FTL50 Liquiphant M Vibronic Level Switch
Description
FTL50 Liquiphant M modular vibronic level switch
The Endress+Hauser FTL50 is the compact version of the Liquiphant M, a vibronic point level switch for liquids that uses a tuning fork to detect the presence of medium. It is designed for a wide range of process connections, a choice of housings and plug-in electronic inserts, and a long list of approvals. Where the FTL31 and FTL33 are compact switches with fixed electronics, the FTL50 is a modular instrument for process plant: you choose the housing, the electronics, the connection and the materials separately.
The datasheet covers the whole family: FTL50 (compact), FTL51 (with extension pipe up to 3 m, and up to 6 m on request), FTL50H (compact, polished fork and hygienic connections) and FTL51H. The FTL50 handles process temperatures from –50 to +150 °C and pressures up to 64 bar, and it is a recognised choice for overfill and dry-run protection in oil and gas, chemical and utility tanks.
FTL50 technical specifications
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Endress+Hauser / FTL50 (Liquiphant M, compact; family datasheet TI00328F) |
| Measuring principle | Vibronic tuning fork; frequency falls when covered by liquid |
| Process temperature | –50 to +150 °C (–58 to +302 °F) |
| Process pressure | –1 to 64 bar (up to 100 bar for the FTL51 option) |
| Density | Standard 0.7 g/cm³; 0.5 g/cm³ selectable on the electronics |
| Viscosity / solids | Up to 10,000 mm²/s; solid particles up to 5 mm diameter |
| Maximum measured error | ±1 mm; repeatability 0.1 mm; hysteresis approx. 2 mm |
| Switching delay | 0.5 s covered, 1.0 s uncovered; 0.2, 1.5 or 5 s on request |
| Wetted materials | 316L (1.4404 or 1.4435); fork 316L (1.4435); option Alloy C22 (2.4602) |
| Housings | Polyester (PBT), stainless steel 316L, aluminum (coated), and a compact stainless housing with IP69 option |
| Ambient temperature | Up to +70 °C, depending on medium temperature; storage –50 to +80 °C |
| Lateral load capacity | 75 Nm |
| Safety | SIL2/SIL3 per IEC 61508 / IEC 61511-1 with suitable electronics; fork damage monitoring |
FTL50 electronic inserts
The most important FTL50 ordering decision is the electronic insert, which sets the supply, output and Ex options. The table lists the variants documented in the technical information.
| Insert | Supply and output |
|---|---|
| FEL51 | 2-wire AC, 19 to 253 V AC, switches the load directly in the supply line |
| FEL52 | 3-wire DC PNP, 10 to 55 V DC, load current up to 350 mA, for PLC inputs |
| FEL54 | Universal AC 19 to 253 V or DC 19 to 55 V, relay output with two floating changeover contacts |
| FEL55 | 2-wire, 11 to 36 V DC, 8/16 mA signal for 4 to 20 mA input modules |
| FEL56 / FEL58 | NAMUR (EN 50227) L-H or H-L edge for a separate switching unit |
| FEL57 | PFM pulse signal on two wires, with proof test from the switching unit |
| FEL50A | PROFIBUS PA discrete input, profile 3.0 |
| FEL50D | Continuous density measurement with the Density Computer FML621 |
How the FTL50 operates
The sensor fork vibrates at its intrinsic frequency, and the frequency decreases when liquid covers it. The electronic insert detects the change and switches. The FTL50 is therefore independent of flow, turbulence, bubbles, foam, vibration, solids content and build-up, and it has no moving parts that wear. Switching can be set to the safe state for the process: MAX for overfill, MIN for dry-run protection, selected on the electronic insert.
Switch points depend on mounting position and on the liquid density. The datasheet gives a reference switch point under water at 23 °C and 0 bar with vertical mounting from above. The FTL51 extension pipe lets you reach a level point deep in a tank from the top connection; with a long pipe the unit must be installed vertically, while compact and short-pipe versions up to approx. 500 mm can be mounted in any position.
FTL50 connections, housings and materials
Process connections include threaded versions such as G 3/4 and G 1 and flanges following EN 1092-1, ASME B16.5 and JIS B2220, with wetted parts in 316L and optional Alloy C22 for aggressive media. Housings include polyester, stainless steel and coated aluminum, with the stainless compact housing offering IP69 for intensive cleaning. Flange plating with Alloy C22 is available. Material certificates according to EN 10204 3.1, NACE MR0175/MR0103 conformity and a leak detection approval under WHG (Z-65.40-446) can be ordered.
FTL50 selection and ordering checklist
- Compact FTL50 or extension-pipe FTL51, and pipe length if required.
- Hygienic versions FTL50H or FTL51H for food and pharmaceutical processes.
- Electronic insert (FEL51 through FEL50D) matching your PLC, relay or NAMUR switching unit.
- Housing material and ingress protection, plus cable gland or plug.
- Process temperature and pressure, and whether the 100 bar option is needed on FTL51.
- Fluid density and viscosity; density setting of 0.5 or 0.7 g/cm³.
- Hazardous area approvals (ATEX, IECEx and others listed in the safety instructions), SIL requirement and material certificates.
Installing and maintaining the FTL50
Install the unit so that the fork can drain freely and is clear of deposits. With the ambient temperature at the housing limited by the medium temperature, a temperature spacer or a pressure-tight feedthrough extends the usable range on hot or very cold tanks. The FEL58 insert lets you check the connecting cabling by pressing a key, and the FEL57 supports a proof test from the switching unit without changing level. Replace electronic inserts as plug-in modules if the supply or signal type changes; the sensor stays in the vessel.
FTL50 applications in Oman and the GCC
The FTL50 suits storage-tank overfill protection, knock-out drums, lube-oil and seal-oil reservoirs, boiler feed and condensate tanks, desalination chemical dosing tanks and fuel and diesel tanks. In upstream and downstream plants in Oman and the GCC the wide temperature range, 316L or Alloy C22 wetted parts and the choice of Ex and SIL-capable electronics are the reasons it is specified. Seven Star LLC supplies Endress+Hauser instruments as an independent supplier in Muscat to operators and contractors across the GCC.
Information to send with an FTL50 RFQ
- Order code or nameplate photo of the existing FTL50, FTL51 or Liquiphant M.
- Medium, density, viscosity, temperature and pressure.
- Tank connection (thread or flange standard, size and rating) and extension pipe length.
- Electronic insert, housing, cable entry and hazardous area approval.
- Functional safety requirement, certificates and quantity.
Documents and quotation
The Endress+Hauser Technical Information for the Liquiphant M FTL50, FTL51, FTL50H and FTL51H is attached on this page as a datasheet, covering every electronic insert and housing.
Send us the FTL50 order code or your application data, and we will prepare a quotation for delivery in Oman and the GCC.
Other Models in the Eh Liquiphant Vibronic Range
Seven Star LLC supplies models from the Eh Liquiphant Vibronic range in Oman and the GCC. Compare the related models below and request a quote for the one that matches your application.
| Model | Category | |
|---|---|---|
| Endress+Hauser FTL31 Liquiphant Vibronic Level Switch | Level Instrumentation | View details |
| Endress+Hauser FTL33 Liquiphant Hygienic Level Switch | Level Instrumentation | View details |
| Endress+Hauser FTL50 Liquiphant M Vibronic Level Switch | Level Instrumentation | You are viewing this model |
Datasheets & Documents
- Datasheet Endress+Hauser Liquiphant M FTL50 Technical Information Download
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About brand
Endress+Hauser makes process measurement instruments for flow, level, pressure, temperature and liquid analysis. Georg H. Endress and Ludwig Hauser started the business in Lörrach, Germany, on 1 February 1953, first selling level meters, and the Endress+Hauser name has been used since 1957. The group is headquartered in Reinach, Switzerland, and has been wholly owned by the Endress family since 1975.
Seven Star LLC is an independent supplier listing Endress+Hauser flowmeters, level and pressure transmitters, temperature assemblies and liquid analysis products for buyers in Oman and the GCC. Instruments are matched from the full order code on the nameplate.
Endress+Hauser company profile
| Origin | Founded in Lörrach, Germany, on 1 February 1953 by the Swiss engineer Georg H. Endress and Ludwig Hauser |
|---|---|
| Headquarters | Endress+Hauser AG, Reinach (Basel-Landschaft), Switzerland |
| Ownership | Family owned; the Endress family has been the sole shareholder since 1975, and a family charter commits the company to stay family owned |
| Size | About 16,500 employees and sales of about EUR 3.7 billion (2023, as reported by the company) |
| Product families | Proline flowmeters, Micropilot and Levelflex radar, Liquiphant switches, Cerabar and Deltabar pressure, iTEMP and iTHERM temperature, Liquiline and Memosens liquid analysis |
Milestones
- 1953: Georg H. Endress and Ludwig Hauser start the business in Lörrach on 1 February, first selling level meters.
- 1957: The Endress+Hauser name comes into use.
- 1975: The Endress family becomes sole shareholder.
- 2023: About 16,500 employees and sales of about EUR 3.7 billion, as reported by the company.
Endress+Hauser product lines
| Line | Measuring principle | Typical use |
|---|---|---|
| Promass F 300, Promass 80F, 83F/84F | Coriolis mass flow | Direct mass flow and density of liquids and gases, hydrocarbon transfer and chemical dosing |
| Promag P 300, P 500, H 300, W 400, W 10, 50P | Electromagnetic flow | Water, wastewater, slurries and other conductive liquids |
| Prowirl F 200, 72F | Vortex flow | Steam, gas and low-viscosity liquids |
| Prosonic Flow 92F, t-mass 65F | Ultrasonic and thermal mass flow | Water lines; compressed air and industrial gases |
| Micropilot FMR62, FMR67, FMR60, FMR10B, FMR20, FMR50, FMR52 | Free-space radar level, 80 GHz and 26 GHz | Tanks, process vessels, silos and open water channels |
| Levelflex FMP51, FMP50, FMP54, FMP55 | Guided wave radar level | Level and interface in vessels, separators and bypass chambers |
| Liquiphant FTL51, Prosonic S FMU90 | Vibronic point level; ultrasonic level | High and low level alarms, pump protection, open channel flow |
| Cerabar PMC71B, PMP51B, PMP71, Deltabar PMD78B, PMD75 | Pressure and differential pressure | Process pressure, hydrostatic level and DP flow |
| iTEMP TMT82, TMT162, iTHERM TM101, TR66, TR10 | Temperature transmitters and thermometers | RTD and thermocouple points with thermowells |
| Liquiline CM444, CM442, Memosens CPS11E, Stamolys reagents | Liquid analysis | pH, ORP, conductivity, dissolved oxygen and nutrient analysis in water treatment and process |
Where Endress+Hauser instruments are used
In Oman and the GCC, Endress+Hauser instruments are common in oil and gas production and processing, refineries and petrochemicals, desalination and water networks, wastewater treatment, power plants and food and beverage plants. Coriolis meters measure hydrocarbon and chemical flows, electromagnetic meters cover water and wastewater, radar transmitters handle tank and silo level, and Liquiline analysers monitor water quality. Proline 300 and 500 flowmeters include Heartbeat Technology for in-situ verification, which reduces the need to remove a meter for checks.
Ordering Endress+Hauser instruments: what we need
The order code on the nameplate (for example PMP71-1QA1S11RDADU) defines every option: measuring range, process connection, materials, output, approvals and display. Send it with the serial number; Endress+Hauser can retrieve the original configuration from the serial number. For a new instrument add the medium, operating and design pressure and temperature, range, line size or tank geometry, process connection, wetted materials, output or protocol (4-20 mA HART, PROFIBUS, FOUNDATION Fieldbus, Modbus) and the hazardous-area approval required. Older models such as Promass 80/83 or Micropilot M are replaced by current Proline or 80 GHz Micropilot devices.
Facts checked against Endress+Hauser company history and product information, October 2026.
Browse Endress+Hauser products by category: Flowmeters, Level Transmitter, Pressure Instrumentation, Temperature, Liquid Analysis Sensors, Liquid Analytical Systems.
FAQ
Questions about the Endress+Hauser FTL50 Liquiphant M Vibronic Level
Answers from our engineering team on installation, compatibility and integration.
01What is the difference between FTL50, FTL51 and the H versions?
FTL50 is the compact design, FTL51 adds an extension pipe up to 3 m (6 m on request), and the H versions FTL50H and FTL51H have a polished fork and hygienic process connections for food and pharmaceutical use. All share the same electronic inserts.
02Which electronic inserts can be fitted to the FTL50?
The datasheet lists FEL51 (2-wire AC), FEL52 (3-wire DC PNP), FEL54 (AC/DC relay), FEL55 (8/16 mA), FEL56 and FEL58 (NAMUR), FEL57 (PFM), FEL50A (PROFIBUS PA) and FEL50D (density measurement). The choice follows your control system and any Ex requirement.
03What process conditions does the FTL50 cover?
Process temperature is -50 to +150 °C and pressure is -1 to 64 bar for the FTL50, with a 100 bar option listed for the FTL51. Viscosity up to 10,000 mm²/s and solid particles up to 5 mm diameter are permitted.
04Is the FTL50 suitable for safety systems?
The datasheet recommends the Liquiphant M for safety systems requiring SIL2/SIL3 per IEC 61508 and IEC 61511-1 with the appropriate electronic insert, and the fork is monitored for damage. Functional safety manuals are referenced for the relevant electronics.
05How accurate is the FTL50 switch point?
Under reference conditions the maximum measured error is ±1 mm, repeatability is 0.1 mm and hysteresis is about 2 mm. The switch point depends on the mounting position and the density of the liquid.
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