Technical Characteristics and Operational Versatility
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Mid-Range Capability: The FMU41 extends the compact transmitter performance to reach up to 8 meters in liquids and 3.5 meters in bulk solids. This makes it a versatile solution for municipal water management, chemical processing, and industrial material handling.
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Advanced Signal Diagnostics: A standout feature is the four-line plain text display that provides on-site visualization of the envelope curve. This allows operators to perform advanced echo analysis, ensuring the sensor ignores false reflections from agitators, heating coils, or vessel walls.
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Flexible Electrical Integration: The device is available in both two-wire (loop-powered) and four-wire versions. This flexibility allows it to fit into standard control loops or applications where a separate power supply is preferred for higher signal output.
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Precision Temperature Compensation: Sound velocity changes with temperature. The FMU41 includes an integrated temperature sensor that compensates for these fluctuations in real-time, maintaining high accuracy even in outdoor silos or tanks exposed to direct sunlight.
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Maintenance-Free PVDF Sensor: The sensor is hermetically sealed, potted, and constructed from high-quality PVDF. This ensures it remains unaffected by corrosive liquids or moisture ingress, significantly reducing service requirements compared to mechanical level indicators.
Technical Specification Matrix
| Feature | Technical Details |
| Measuring Principle | Ultrasonic (Non-contact) |
| Max. Range (Liquids) | 8 m (26 ft) |
| Max. Range (Solids) | 3.5 m (11 ft) |
| Blocking Distance | 0.35 m (1.15 ft) |
| Process Temperature | -40 to +80 °C (-40 to +176 °F) |
| Process Pressure | 0.7 to 3 bar (10 to 44 psi) |
| Sensor Material | PVDF (Hermetically sealed) |
| Degree of Protection | IP 68 (Sensor) / IP 66 (Housing) |
Primary Applications
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Medium-Sized Storage Tanks: Level monitoring for oils, fuels, water, and aggressive chemicals.
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Open Channel Flow: Measuring flow rates in large flumes and weirs using the integrated 32-point linearization function.
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Agitated Vessels: Reliable level detection in process tanks with stirrers or mixers, utilizing adjustable echo suppression.
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Bulk Solids Handling: Monitoring levels in hoppers, at conveyor discharge points, or on small-scale stockpiles.
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Hazardous Area Monitoring: Fully certified for use in explosion-hazardous areas with international Gas-Ex and Dust-Ex approvals.
