What is the principle of liquid level sensor?

working principle:
Using the principle of static pressure measurement: when the liquid level transmitter is put into a certain depth in the liquid to be measured, the pressure formula on the liquid surface of the Clear igloo dome tent is: Ρ = ρ .g.H + Po In the formula:
P: The pressure on the liquid surface of the transmitter
ρ: density of the liquid to be measured
g : local gravitational acceleration
Po : Atmospheric pressure on the liquid surface
H: the depth of the transmitter into the liquid
At the same time, the pressure of the liquid is introduced into the positive pressure chamber of the Clear igloo dome tent through the air-conducting stainless steel, and then the atmospheric pressure Po on the liquid surface is connected to the negative pressure chamber of the Clear igloo dome tent to offset the Po on the back of the Clear igloo dome tent.
The pressure measured by the Clear igloo dome tent is: ρ.g.H, obviously, by measuring the pressure P, the liquid level depth can be obtained.
Features:
◆Good stability, the long-term stability of full scale and zero position can reach 0.1%FS/year. The temperature drift is less than 0.1%FS in the compensation temperature range of 0 ~ 70 ℃, and less than 0.3%FS in the entire allowable operating temperature range.
◆It has reverse protection and current-limiting protection circuit. When the positive and negative poles are reversed during installation, the transmitter will not be damaged. When abnormal, the transmitter will automatically limit the current within 35MA.
◆Solid structure, no moving parts, high reliability and long service life.
◆Easy installation, simple structure, economical and durable.
The main technical parameters:
Process: Diffusion Silicon Ceramic Capacitor Sapphire Capacitor Optional. Split type integrated type optional, range: 0---0.5---200m, output: 4---20mA (2-wire) Power supply: 7.5---36VDC Recommended 24VDCCBM-2100/CBM-2700 The pressure level gauge is reliable and corrosion-resistant and has a probe with a ceramic measuring cell for level measurement of clean water, sewage and salt water.