Precise Radar Control with the NGM from KOBOLD

The modular constructed NGM of KOBOLD works on the principle of Time Domain Reflectometry (TDR, also known as guided Microwave or guided Radar) and offers an excellent alternative to conventional level measurements. The NGM enables precise and reliable continuous level measurement and point level detection in almost all liquids. This innovative device has almost no installation restrictions - it can be mounted in small tanks, tall and narrow nozzles and it measures precisely even with difficult tank geometries or close to interfering structures.

Exact and speedy level measurement is a challenge, especially in small vessels. Small vessels can have very high filling speeds (approx. 200-400 mm/s, depending on the pump used), so that fast response times are necessary. Conventionally, capacitance level meters have been used in small tanks.
The disadvantages of capacitance level meters are their dependence on medium dielectric constants and a specific probe calibration in tanks. NGM is ideal for various types of processing and storage applications and has an exceptional performance in liquids with low dielectric constants (low reflectivity) such as oils and hydrocarbons. NGM uses TDR Technology: low-energy, high frequency electromagnetic impulses, generated by the sensor´s circuitry, are propagated along the probe which is immersed in the liquid to be measured. When these impulses hit the surface of the liquid, part of the impulse energy is reflected back up the probe to the circuitry which then calculates the fluid level from the time difference between the impulses sent and the impulses reflected. The sensor can output the analyzed level as a continuous measurement reading through its analogue output, or it can convert the values into a freely adjustable switching output signal. The existing 2-wire TDR meters have restricted speeds, as only limited energy is available. The NGM is a 4-wire unit with sufficient power to measure evidently fast and reliable.


  • Unstable process conditions - Changes in viscosity, density, or acidity do not affect accuracy.
  • Agitated surfaces - Boiling surfaces, dust, foam, and vapour do not affect device performance.
  • TDR also works with re-circulating fluids, propeller mixers, and aeration tanks.
  • High temperatures and pressures - NGM performs well in temperatures up to +250 °C and can withstand pressures up to 40 bar.
  • Fine powders and sticky fluids - NGM works with vacuum tanks filled with used cooking oil as well as tanks holding paint, latex, animal fat, soybean oil, sawdust, carbon black, titanium tetrachloride, slat, and grain.
  • Hazardous area ATEX certification
  • Factory settings may be configured via HART® Modem.




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  • NGM measures up to 70 times per second compared with a 2-wire unit in contrast only once a second.
  • Generates multiple accurate measurements each second producing a reliable evaluation of level signal.
  • Standard reaction time of 0.5s
  • Detection of level changes of up to 1000 mm/s .
  • 4-wire design offers a highly robust measurement due to innovative signal analysis and disturbance signal suppression.
  • Fully modular probe design for simple installation
  • Economically priced.
  • Using TDR the NGM offers measurement readings that are independent of the chemical or physical properties of the process media with which it is in contact.