The working principle of FMCW radar level transmitter
The radar signal is emitted through the antenna, which is reflected on the surface of the product and received after time t. The principle of the radar used is FMCW (Continuous Modular Frequency Wave). FMCW – Radar transmits a high frequency signal whose frequency increases linearly during the measurement phase (called the frequency sweep). The signal is emitted, reflected from the measurement surface and received with a time delay. Be, t. Delay time, t = 2d / c, where d is the distance to the product surface and c is the speed of light in the gas above the product. For further signal processing, the difference Δf is calculated from the actual transmission frequency and the receiving frequency. The difference is directly proportional to the distance. Large frequency differences are related to long distances and vice versa. The frequency difference Δf is converted to the frequency spectrum by the Fourier transform (FFT) and then the distance from the spectrum is calculated. This level is obtained from the difference between the height of the tank and the measuring distance.
Radar level measurement is a safe product even in extreme process conditions (pressure, temperature) and vapors. It can also be used in sanitary applications to measure non-contact levels. Micropilot versions are available for a variety of industries such as water / wastewater, food industry, life sciences or process industries. Different antenna versions are available for any type of radar application.
- Measurement without contact, without maintenance
- Under the influence of moderate properties such as density and conductivity, it is not affected by bulk solids by filling with noise and dust.
- Free measurement range
- For high temperatures up to + 450 ° C / + 842 ° F