What is the principle of heavy hammer level gauge?

Heavy hammer level gauge is a kind of level gauge used to measure the height of solid materials. Because the measured substance is solid and cannot float like a liquid, intermittent measurement is often used. After receiving the measurement signal, the stepping motor controls the heavy hammer to fall until it falls to the surface of the material, then the gravity decreases, and then the heavy hammer is lifted in the opposite direction to avoid being buried. The falling distance is converted into a digital signal for remote transmission and decoded into a material height for display and control.