The KOBOLD NGR is a guided wave radar level transmitter that uses time domain reflectometry (TDR) to provide continuous level measurement and an adjustable switching point for oil and water-based liquids. It operates independent of density, temperature, pressure, humidity, and conductivity, and is designed to install without calibration.
How the NGR Guided Wave Radar Level Transmitter Works
The NGR sends low-energy electromagnetic pulses along a probe and measures the time difference between the transmitted pulse and the pulse reflected at the liquid surface. That time-of-flight is converted into level, delivered both as a continuous analog value and as an adjustable switching output. Setup uses four buttons and an integral display.
Media, Temperature, and Pressure Range
The NGR measures free-flowing, oil and water-based liquids at process temperatures of -4 to 212 F (-20 to 100 C) and process pressures of -14.5 to 145 PSI (-1 to 10 bar). Measurement is independent of density, temperature, pressure, humidity, and conductivity.
- Accuracy of the sensor element: plus or minus 0.2 in under reference conditions
- Repeatability better than or equal to 0.08 in; resolution below 0.08 in
- Response time below 400 ms; initialization time under 2 s
- Dielectric constant (DK) of 5 or higher for a single probe, 1.8 or higher with a concentric tube
Probe Types and Measuring Lengths
Three interchangeable probe styles cover different tanks and ranges, and the monoprobe and wire rope can be shortened in the field.
- Monoprobe: field-adjustable from 0.66 to 6.56 ft (0.2 to 2 m); a standard probe can be cut from 8 to 78 in (200 to 2000 mm), or extended to 157 in (4000 mm) with a user-supplied probe
- Wire rope: field-adjustable from 3.28 to 13 ft (1 to 4 m) for longer ranges
- Concentric tube: designed for plastic tanks or media with DK above 1.8
Outputs, Electrical Connection, and Enclosure
The NGR provides a 3-in-1 output that combines an integral display, an analog signal, and a switching signal on one device. The analog output follows NAMUR NE 43.
- Analog output: 4-20 mA / 0-10 V, switchable
- Switching output: one PNP plus one PNP/NPN (Option 2), or one PNP plus three PNP/NPN (Option 4), user selectable
- Supply voltage 12 to 30 VDC; power consumption at or below 100 mA at 24 VDC without output load
- Electrical connection M12x1, 5-pin or 8-pin; IO-Link capable; IP67 enclosure per EN60529
Wetted Materials and Installation
Wetted parts are 316L stainless steel and PTFE, with a PBT housing and a 3/4 in NPT or G3/4 A process connection. The rotatable housing simplifies mounting, and several units can be installed near each other without interference.
- Single probe in a metal tank: nozzle depth 1 in or more, at least 2 in from the tank wall or bottom, 0.4 in minimum at the probe end, and 4 in or more to other fittings
- A concentric tube requires no minimum distance to the tank wall or other fittings and suits metallic and non-metallic tanks
- Single probe in an immersion tube or metal bypass: inside diameter 1.5 in or more
Guided Wave Radar Level Transmitter: Made in the USA
The KOBOLD NGR guided wave radar level transmitter is made in the USA. It is designed and built to support consistent quality control and responsive technical support, with field-adjustable probe lengths and an intuitive four-button user interface.
Easy Integration into New or Existing PLC Systems
The NGR combines a 4-20 mA analog signal and a transistor switching signal in one output system. The analog output complies with NAMUR NE 43 and connects directly to PLC analog input cards, while the integral display supports setup and verification of PLC communications.
Choosing Between the NGM and the NGR
Both are KOBOLD guided wave radar level transmitters. The NGR is designed for compact installation in small vessels, field-adjustable probe lengths, an integral display and button interface, combined switching and analog outputs, and quick setup without calibration. Consider the NGM for extended measurement range (up to 65.6 ft), a wider temperature range (-320 to 480 F), higher pressure applications (up to 580 PSIG), and complete galvanic isolation.
Common Questions about NGR - Guided Wave Radar Level Transmitter
It uses guided radar. A low-energy electromagnetic pulse travels down the probe, reflects at the liquid surface, and returns; the transmitter calculates level from the round-trip time. The result is reported as a continuous analog reading and an adjustable switch point, so one device handles monitoring and detection.
The transmitter is rated for process media between -4 and 212 F (-20 to 100 C), at pressures of -14.5 to 145 PSI (-1 to 10 bar). Ambient operation is allowed from -4 to 140 F (-20 to 60 C), with storage down to -40 F (-40 C) and up to 176 F (80 C). Its enclosure carries an IP67 rating per EN60529.
Three styles are offered: a monoprobe that adjusts between 0.66 and 6.56 ft (0.2 to 2 m), a wire rope spanning 3.28 to 13 ft (1 to 4 m), and a concentric tube for plastic vessels or low-DK media. A single probe needs a dielectric constant of 5 or higher, while a concentric tube works from 1.8.
It offers a switchable 4-20 mA / 0-10 V analog output that follows NAMUR NE 43, plus PNP/NPN switching outputs (one PNP with one PNP/NPN, or one PNP with three PNP/NPN). Supply is 12 to 30 VDC through an M12x1 5-pin or 8-pin connector, and the device is IO-Link capable.
The parts in contact with the media are made of 316L stainless steel and PTFE, suiting a wide range of oil and water-based liquids. Its body is molded PBT plastic. Threaded process connections are 3/4 in NPT male or G3/4 A male, and the head rotates to ease wiring and display orientation after mounting.
Mounting a single probe in metal calls for a nozzle of at least 1 in, a gap of 2 in or more to the wall or floor of the vessel, 0.4 in of space at the probe tip, and 4 in to nearby fittings. A concentric tube needs no minimum distance to walls or fittings.
No. The transmitter is designed to work in oil and water-based liquids without calibration or recalibration at installation. Because the probe can be cut or exchanged on site, and setup runs from four buttons and the display, the sensor can be adapted to an application quickly during commissioning.
The code follows the order NGR then version, material, signal output, output and switch, connection, and probe length, for example NGR-1 2 4 2 N5 0. Version 1 is a single probe, 2 a concentric tube, and 4 a wire probe; N5 is 3/4 in NPT and G5 is G3/4; 0 is the standard probe length.
Product Specifications
Probe Length
6.5 ft...13 ft (Shorter Lengths are Possible)
Maximum Pressure
145 PSIG
Media Temperature
-4 °F...212 °F (100 °C)
Wetted Parts
316L St. Steel, PTFE
Output Measurement
4-20 mA Continuous, Transistor Switch, IO-Link
Product Features
No Mechanical Moving Parts
Measurement is Independent of Density, Temperature, Pressure and Humidity and Conductivity
Compact and Rotatable Housing Ensures Flexible Installation
Small Inactive Areas, Ideal for Small Vessels
Time and Cost Savings Due to Low Maintenance and Quick Commissioning
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