The NRE-7 is a compact, non-contact radar level transmitter that uses 80 GHz FMCW radar to measure the level of liquids, emulsions, and bulk solids. The 80 GHz (W-band) frequency supports a small antenna, tight beam focusing, and a narrow beam angle down to 7°, so the transmitter installs easily and measures reliably in confined spaces. It provides accuracy up to ±0.078 in (±2 mm) across a measuring range up to 98.5 ft (30 m), with volume, mass, and open-channel flow calculations available in addition to level.
How the NRE-7 measures level
The NRE-7 is a frequency modulated continuous wave (FMCW) radar operating at 80 GHz (77 to 81 GHz, W-band). It transmits millimeter waves toward the surface and calculates distance from the frequency shift of the reflected signal, then converts it to level, volume, or mass. Because millimeter waves need no carrier medium, it also works in vacuum.
Reliable measurement requires a medium dielectric constant (εr) above 1.9.
Measuring range, accuracy, and resolution
The NRE-7 measures up to 98.5 ft (30 m). Accuracy is up to ±0.078 in (±2 mm) on the 1½ in models and ±0.197 in (±5 mm) on the 1 in model, with 0.0039 in (0.1 mm) resolution. Current models cover 33 ft (10 m) and 66 ft (20 m) ranges, and a 98.5 ft (30 m) range is in preparation.
Process ratings and wetted materials
The NRE-7 operates at process and ambient temperatures from -40 to +176 °F (-40 to +80 °C) and process pressure from -14.5 to 43.5 psi (-1 to 3 bar). Wetted parts use PP, PVDF, or PTFE depending on the ordered configuration, and the housing is PP or PVDF plastic. Ingress protection is IP 68.
Antennas and process connections
The NRE-7 uses an encapsulated horn antenna in PP, PVDF, or PTFE, available in 1 in (25.4 mm) and 1½ in (38.1 mm) diameters. Process connections are 1 in or 1½ in BSP or NPT male threads, with PP flanges available as an accessory. Antenna insertion length is 2.2 in (56 mm) or 2.75 in (70 mm).
Output, communication, and power
The NRE-7 is a 2-wire device with a 4-20 mA output and HART communication, plus an optional SPDT relay (30 V/1 A DC, 48 V/0.5 A AC). Supply voltage is 12.5 to 36 VDC. HART supports point-to-point and multidrop operation with up to 15 devices on one loop. Bluetooth is under development.
Applications and compatible media
The NRE-7 measures liquids, emulsions, chemicals, and large-particle bulk solids up to 98.5 ft (30 m). It suits storage tanks, chemical tanks, open pits, sumps, and wells, and it can measure through a plastic tank roof, in vacuum, under a gas blanket, and with media prone to vapor formation. Open-channel flow measurement is also supported.
Industries served
The NRE-7 is applied across the water and wastewater, energy and plant utilities, food and beverage, pharmaceutical, and chemical industries, as well as marine, agriculture, construction materials, heavy industry, and packaging applications.
Installation requirements
For reliable measurement, mount the NRE-7 in a fixed, antenna-down position with the process-connection plane parallel to the measured surface within ±2 to 3°, and keep obstacles out of the beam. On cylindrical tanks, place it at 0.3 to 0.5 of the tank radius and away from the inlet.
- Up to four interfering echoes can be masked using the threshold settings.
- A convex or conical tank bottom should stay covered by at least 3.9 in (100 mm) of liquid for reliable readings.
- As a Local Positioning Radar, the device must observe a 2.48 mi (4 km) separation from radio astronomy sites in the 75 to 85 GHz band; between 2.48 and 24.8 mi (4 to 40 km), mounting height must not exceed 49.2 ft (15 m).
- Foam and heavy vapor can weaken the signal, and the sensor should be shielded from direct sunlight.
Hazardous-area (Ex) version
An intrinsically safe version is available carrying ATEX and IECEx Ex ia approval (ATEX certificate BKI24ATEX0011 X), marked II 1 G Ex ia IIC T5 Ga and II 1 D Ex ia IIIC T95°C Da. The Ex supply voltage is 12 to 30 VDC. Ex ta (dust) variants are in preparation.
Configuration and setup
The NRE-7 ships with factory default settings suitable for basic level measurement and can be configured for a specific process with the free NUS-NTB-NRM-SW software and a HARTCOM HART modem. Configuration covers level, volume, mass, and open-channel flow, plus threshold management to mask clutter. On startup the device draws about 3.5 mA before indicating status through its ECHO and COM LEDs.
Common Questions about NRE-7 - Non-Contact Radar Level Transmitter - Compact Line
It is a 2-wire, 80 GHz non-contact radar transmitter with an integrated, compact design and an IP 68 housing. A single encapsulated horn antenna both sends and receives millimeter-wave signals, so nothing touches the medium. It reports level and can also derive volume, weight, and flow in open channels.
Standard models reach 33 ft (10 m) or 66 ft (20 m), and a 98.5 ft (30 m) version is in preparation. The dead zone at the antenna tip is zero. Maximum range may be reduced with low-dielectric media or non-perpendicular, non-planar surfaces.
Accuracy depends on the model chosen. The 1½ in versions are rated to ±0.078 in (±2 mm) and the 1 in version to ±0.197 in (±5 mm), each under ideal reflecting surfaces. Measured resolution is 0.0039 in (0.1 mm), and readings refresh about once per second.
The NRE-7 handles process and ambient temperatures of -40 to +176 °F (-40 to +80 °C). Process pressure ranges from -14.5 to 43.5 psi (-1 to 3 bar). Its IP 68 housing should be kept out of direct sunlight.
Wetted parts are the encapsulated horn antenna, offered in PP, PVDF, or PTFE. Antenna diameters are 1 in (25.4 mm) and 1½ in (38.1 mm), and threads are BSP or NPT in matching sizes. PP flanges in DIN, ANSI 150, or JIS patterns are available as accessories.
It offers a 4-20 mA analog signal (3.9 to 20.5 mA) with HART on a 2-wire loop, plus an optional SPDT relay rated 30 V/1 A DC and 48 V/0.5 A AC. HART multidrop links up to 15 units, and loop resistance is at least 250 Ω.
Power comes from a galvanically isolated, Category 1 (SELV/PELV) source at 12.5 to 36 VDC, using twisted-pair shielded cable with brown positive and white negative. The standard shielded cable is 16.4 ft (5 m) and can be specified up to 98.5 ft (30 m).
Yes. An intrinsically safe Ex ia model holds ATEX and IECEx approval under certificate BKI24ATEX0011 X, with temperature classes T5 for gas and T95°C for dust and a 12 to 30 VDC supply. Dust ignition-proof Ex ta versions are still in preparation.
The order code sets model, range, material, connection, and output, as in NRE-7 10 A R25 A0K K 0. Range 10 or 20 gives 10 m or 20 m (30 m in preparation); A, B, or T gives PP, PVDF, or PTFE; R or N gives BSP or NPT. A0K is 4-20 mA HART, R0K adds a relay, A0I or A0J add Ex ia, and cable length is set in 1 m steps.