Technical Characteristics and Performance
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80 GHz High-Precision Technology: The NMR81 utilizes a high-frequency signal that produces an exceptionally narrow 3° beam angle. This sharp focus allows the sensor to be installed very close to the tank wall or in nozzles with internal obstructions without receiving interference from false echoes.
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Custody Transfer Accuracy: With a measurement uncertainty of only ±0.5 mm, the device is certified by international bodies like NMi and PTB for legal-for-trade applications. It ensures maximum reliability for volume and mass calculations in fiscal transactions.
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Drip-Off Lens Antenna: The specialized lens antenna is designed with a “drip-off” geometry. This prevents the accumulation of condensate or product droplets on the antenna surface, which typically causes signal attenuation in lower-frequency or flat-antenna radars.
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Safety and Redundancy: Developed according to IEC 61508, the hardware and software are suitable for use in safety-instrumented systems up to SIL3 (in homogeneous redundancy). This provides a dual layer of protection: high-precision measurement for business and high-level safety for plant protection.
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Seamless System Integration: The NMR81 is designed for easy connection to major Distributed Control Systems (DCS) and Tank Inventory Systems. It supports open protocols, simplifying the migration from older tank gauging technologies to modern radar.
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Extreme Range Capability: Capable of measuring distances up to 70 meters, the sensor is suitable for the largest storage tanks and high-capacity spheres used in the petrochemical industry.
Technical Specification Matrix
| Feature | Technical Details |
| Measuring Principle | Free-space Radar (W-band) |
| Frequency | 80 GHz |
| Measuring Range | Up to 70 m (230 ft) |
| Accuracy | ±0.5 mm (±0.02″) |
| Process Temperature | -40 to +170 °C (-40 to +338 °F) |
| Process Pressure | Vacuum to +16 bar (232 psi) |
| Approvals | OIML R85, API 3.1B, NMi, PTB |
| Safety & Compliance | SIL 2/3, WHG, ATEX, IECEx |
Primary Applications
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Fiscal Custody Transfer: Level measurement in high-value liquid storage where results are used for legal billing and taxation.
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Large Storage Terminals: Inventory management for crude oil, refined products, and chemicals in large-diameter tanks.
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Tank Farms with Obstructions: Ideal for tanks with internal heating coils, floating roofs, or complex bracing where a 3° beam is required to bypass obstacles.
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High-Precision Volume Calculation: Providing the primary level data for advanced tank gauging systems to calculate net standard volume.
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Refineries and Petrochemicals: Continuous monitoring of feedstocks and finished products in pressurized or atmospheric vessels.




