The antenna receives the reflected microwave impulse and transmits it to the electric circuit, the micro processor processes this signal, recognizes the wave echo produced by microwave impulse on the substance surface. The correct microwave echo signal recognition is completed intelligent software, the precision can reach millimeter grade. The distance from the substance surface D is proportional to impulse time stroke T:

   D=C ×  T/2

   Among them, C is velocity of light 

As the distance of empty tank E is known, the substance position L is:

L=E-D

Output

By inputting empty tank height E (=O), full tank height F (=full) and some application parameter to set up, the application parameter will make the gauge adapted to the measuring environment, corresponding to 4-20mA output.