Technical Data
CompareContinuous / Liquids
| Measuring Principle | Ultrasonic |
| Characteristic / Application | Separated version with field housing or top hat rail housing for control cabinet instrumentation, 300 m in-between sensor and transmitter |
| Supply / Communication | 4-wire (HART, PROFIBUS DP) |
| Accuracy | +/- 2 mm + 0.17% of measured distance |
| Ambient temperature | -40 °C ... 80 °C (-40 °F ... 176 °F) |
| Process temperature | -40 °C ... 80 °C (-40 °F ... 176 °F) |
| Process pressure / max. overpressure limit | 0.7 bar ... 4 bar abs (10 psi ... 58 psi) |
| Main wetted parts | PVDF (fully welded IP68 / NEMA6P) |
| Process connection | G / NPT 1" |
| Blocking distance | 0.3 m (1 ft) |
| Max. measurement distance | Liquids: 10 m (33 ft), Solids: 5 m (16 ft) |
| Communication | Transmitter: 4 ... 20 mA HART PROFIBUS DP |
| Certificates / Approvals | ATEX, FM, CSA, IEC Ex, INMETRO, NEPSI, UK Ex |
| Options | Second 4...20 mA output |
| Components | Transmitter: FMU90, FMU95 |
| Application limits | Foam / high turbulence possible: FDU92 Flange-flush assembly: FDU91F For tank farms scanner: FMU95 |
Continuous / Solids
| Measuring Principle | Ultrasonic |
| Characteristic / Application | Separated version with field housing or top hat rail housing for control cabinet instrumentation, 300m in-between sensor and transmitter |
| Supply / Communication | 4-wire (HART, PROFIBUS DP) |
| Accuracy | +/- 2mm + 0.17% of measured distance |
| Ambient temperature | -40 °C ... 80 °C (-40 °F ... 176 °F) |
| Process temperature | -40 °C ... 80 °C (-40 °F ... 176 °F) |
| Process pressure / max. overpressure limit | 0.7 bar ... 4 bar abs (10 psi ... 58 psi) |
| Main wetted parts | PVDF (fully welded IP68 / NEMA 6P) |
| Process connection | G / NPT 1" |
| Blocking distance | 0.3 m (1 ft) |
| Max. measurement distance | Liquids: 10 m (33 ft), Solids: 5 m (16 ft) |
| Communication | Transmitter: 4 ... 20 mA HART PROFIBUS DP |
| Certificates / Approvals | ATEX, FM, CSA, IEC Ex, INMETRO, NEPSI, UK Ex |
| Options | Second 4...20mA output |
| Components | Transmitter: FMU90 |
Liquids
| Measuring Principle | Ultrasonic |
| Product headline | Version with separate transmitter in field housing or top hat rail housing Cost effective solution for open channel flow measurement in water / wastewater plants |
| Max. measurement error | Accuracy: distance measurement: +/- 2mm + 0.17% |
| Measuring range | Up to 10m / 32ft |
| Max. process pressure | 0.4 bar...4 bar (10 psi...58 psi) |
| Medium temperature range | -40...80°C (-40...176°F) |
| Degree of protection | IP68 |
| Display/Operation | Transmitter FMU90 |
| Outputs | Transmitter: 4...20mA HART PROFIBUS DP |
| Inputs | Transmitter FMU90 |
| Digital communication | HART, PROFIBUS DP |
| Hazardous area approvals | ATEX, FM, CSA, IEC Ex, INMETRO, NEPSI, UK Ex |
The FDU91 ultrasonic sensor is suitable for continuous, non-contact level measurement of liquids, pastes, sludge, powders and coarse bulk solids. It is maintenance-free and can also be used for flow measurement in open channels and measuring weirs. The measured value is unaffected by dielectric constant, density or humidity, and the sensor's self-cleaning function eliminates the influence of medium buildup on the measurement. Suitable for hazardous areas; maximum measuring range: liquid 10 m (33 ft), solid 5 m (16 ft).
Benefits
Built-in temperature sensor for time-of-flight calibration. Precise measurement even when the temperature changes
Hermetically welded PVDF sensor for applications with the highest corrosion resistance requirements
Suitable for harsh climatic conditions; sensor and transmitter can be installed separately at a maximum distance of 300 m
Self-cleaning sensor function reduces buildup formation
Built-in automatic sensor detection; easy commissioning when connected to the FMU90/FMU95 level transmitter
Degree of protection IP68
Optional sensor heater prevents icing and ensures reliable measured values
Application areas
Continuous, non-contact level measurement of liquids, pastes, sludge, powders and coarse bulk solids; flow measurement in open channels and measuring weirs. Maximum measuring range: liquid 10 m, solid 5 m; suitable for hazardous areas; other measuring ranges: FDU92: liquid 20 m, solid 10 m; FDU93: liquid 25 m, solid 15 m; FDU95: solid 45 m; FDU96: solid 70 m
Spare Parts & Accessories 12
12 spare parts · click to collapse
| Order code | Description | |
|---|---|---|
| 71395801 | FTI26 Lock NutMounting aid. Material: plastic PA. Wrench size: 41mm. Usage: FDU90/FDU91/FDU92, FMR10/FMR20, FTC968 AC, FTI26. | Details |
| 71452323 | Wall-mounted sensor bracket, 316LMaterial: 316L. Usage: FMR10B, FMR20B, FMR30B, FDU90, FDU91, FDU91F, FDU92, FDU93, FDU95, FMR10, FMR20, FMU30, FMU40, FMU41. | Details |
| 71452315 | Sensor bracket 500 mm, 316LMounting 1" sensor. Material: 316L. Usage: FDU90, FDU91, FDU91F, FDU92, FDU93, FDU95, FMR10, FMR20, FMR10B, FMR20B. | Details |
| 71452316 | Sensor bracket 1000mm, 316L, US-sensorMounting 1" sensor. Material: 316L. Usage: FDU90, FDU91, FDU91F, FDU92, FDU93, FDU95, FMR10, FMR20, FMR10B, FMR20B. | Details |
| 71093130 | mounting bracketMaterial: 316L. Usage: FDU90/FDU91/FDU91F/FDU92/FDU93/FDU95, FMR10, FMR20. | Details |
| 71452326 | Bracket 1400mm, 316LPipe diameter: 1". Material: 316L. Usage: FMR10B, FMR20B, FMR30B, FDU90, FDU91, FDU91F, FDU92, FDU93, FDU95, FMR10, FMR20, FMU30, FMU40, FMU41. | Details |
| 71452327 | Bracket 700 mm, 316LPipe diameter: 1". Material: 316L. Usage: FMR10B, FMR20B, FMR30B, FDU90, FDU91, FDU91F, FDU92, FDU93, FDU95, FMR10, FMR20, FMU30, FMU40, FMU41. | Details |
| 52025686 | Sunshade材质：PVDF 适合FDU90/FDU91, FMR10, FMR20. | Details |
| 71027742 | extension cableLiYCY/CUL 2x(0,75) to connect to FMU90/FMU95 Price per meter | Details |
| 71027746 | extension cableLIYY/CUL 2x(0,75)D+2x0,75 to connect to FMU90/FMU95 Price per meter | Details |
| FAX50- | Threaded Flange FAX50Usage: FMP50, FMP51, FMP52, FMP53, FMP54, FMP55, FMP56, FMP57, FMR20, FMR20B, FMR30B, FMR60, FMR67, FMR60B, FMR66B, FMU30, FMU40, FMU41, FMU42, FMU44, FDU90, FDU91, FDU92, FDU93, FDU95, FTI51, FTI52, FTI55, FTI56, FTI77. | Enquire |
| FAU40- | Mounting Accessories TTP FAU40Aiming ultrasonic sensors for optimum echo signal in separate version. Usage: FDU-sensors. Also for use in ATEX II 1/2D. | Enquire |
Configurator / Comparison
Measuring principle video
Click to playSource: public information from the Endress+Hauser website
Manuals & Documents 11
All documents for this model11 documents · click to expand
TI 焊接接头、过程转接头和法兰 Chinese
Prosonic S FDU90/91/91F/92/93/95/96 技术资料 Chinese
TI FAU40天线角度调节装置 Chinese
TI Prosonic S FDU91 Chinese
TI 文丘里水槽QV302...QV316 Chinese
TI Weld-in adapter, process adapter and flanges English
Prosonic S FDU90, FDU91, FDU91F, FDU92, FDU93, FDU95 English
FAU40 alignment unit English
TI Prosonic S FDU91 English
TI Khafagi-Venturi QV302 to QV316 English
Alignment Unit FAU40 Technical Information English
Case Studies
Municipal Wastewater Treatment · ultrasound — Application Case
Application Context
the inlet, biological and outlet stages of a municipal plant is a typical Municipal Wastewater Treatment duty. The project started from ultrasound , focusing on ultrasonic liquid level measurement or interface detection.
Process Constraints
effluent parameters drift and probes foul with sludge and biofilm, and high solids and corrosive fractions, with large diurnal flow swings only amplify it. The ultrasound specification must therefore cover sizing range against dead zone, mounting height and medium temperature.
Delivery Approach
Delivery was handled as the level range — level solution matched to the actual tank and silo geometry. Execution centred on sizing range against dead zone, mounting height and medium temperature, together with stable compliance with Grade 1A discharge limits and online data reporting.
Field Results
Operation shows the benefit clearly — retrofit without touching the tank, with short installation time, with confidence in this measuring point improving markedly.
Food & Beverage · ultrasound — Application Case
Customer Profile
The typical setting in Food & Beverage is dosing, pasteurising, filling and CIP stages. The measuring point is ultrasound ; the focus is ultrasonic liquid level measurement or interface detection.
Key Difficulties
Conditions are syrups, dairy and beverages that scale easily, under strict hygienic requirements and, on top of that, frequent cleaning demands instruments that withstand hot CIP/SIP caustic cycles, which a standard configuration cannot handle for long. The design therefore starts with sizing range against dead zone, mounting height and medium temperature.
Implementation
The scope ran through the level range: level solution matched to the actual tank and silo geometry. Technically it hinges on sizing range against dead zone, mounting height and medium temperature, and on these requirements: food-safety and hygienic design per 3-A / EHEDG.
Customer Benefit
In practice this means retrofit without touching the tank, with short installation time, which cut the workload on the site maintenance team.
Chemical & Pharmaceutical · ultrasound — Application Case
Project Background
The project covers reactors, metering vessels and finished-product tanks. The work centres on ultrasound and the core task is ultrasonic liquid level measurement or interface detection.
Operating Challenges
The medium and duty are characterised by highly corrosive media with solvents and crystallisation, partly in explosive atmospheres, and corrosion plus Ex protection shortens instrument life and makes downtime costly. So ultrasound cannot be specified generically — it calls for sizing range against dead zone, mounting height and medium temperature.
Solution
The Ainstru engineering team worked through the level range: level solution matched to the actual tank and silo geometry. The configuration involves sizing range against dead zone, mounting height and medium temperature, with these requirements in view: Ex certification and GMP traceability of records.
Results
Since start-up the system has run steadily; the practical result is retrofit without touching the tank, with short installation time.
Power & Energy · ultrasound — Application Case
Project Overview
The site is boiler feedwater, turbine condensate and FGD/DeNOx systems. The customer wanted ultrasound properly configured on the existing plant, with the aim of ultrasonic liquid level measurement or interface detection.
Technical Challenges
What actually causes trouble is high temperature and pressure with both steam and saline water, and drift under high temperature and pressure, with very costly unplanned outages. All of this means the ultrasound configuration has to involve sizing range against dead zone, mounting height and medium temperature.
Configuration
Supply and installation were organised through the level range: level solution matched to the actual tank and silo geometry. On site this meant sizing range against dead zone, mounting height and medium temperature, checked line by line against: compliance with power-industry codes and unit availability targets.
Performance
After commissioning the outcome is retrofit without touching the tank, with short installation time, and the readings are now used for process tuning.
Related Products
Endress+HauserProsonic T FMU30
Endress+HauserProsonic S FMU90
Endress+HauserProsonic M FMU40
Endress+HauserProsonic M FMU42
Endress+HauserProsonic M FMU41
Endress+HauserProsonic S FMU95
Endress+HauserProsonic S FDU91F
Endress+Hauser