What is the function and principle of a pressure transmitter

A typical pressure transmitter mainly consists of three parts: a pressure sensor (also known as a pressure sensor), a measurement circuit, and process connectors. It can be divided into three types: general pressure transmitters (0.001MPa~35MPa), micro differential pressure transmitters (0-1.5kPa), and negative pressure transmitters 

The main function of a pressure transmitter is to transmit pressure signals to electronic devices, and then display the pressure on a computer. The principle is roughly to convert the mechanical signal of water pressure into an electronic signal of current (4-20mA). Pressure is linearly related to the magnitude of voltage or current, usually in a proportional relationship. So, the voltage or current output by the transmitter varies with pressure.

From this, a relationship between pressure and voltage or current can be derived

The two pressures of the measured medium of the pressure transmitter are introduced into the high and low pressure chambers, and the pressure in the low pressure chamber is atmospheric pressure or vacuum, acting on the isolation diaphragms on both sides of the δ element (i.e. component), and transmitted to both sides of the measuring diaphragm through the isolation diaphragms and the filling liquid inside the component. A pressure transmitter is composed of a measuring diaphragm and an electrical capacitor on both sides of the insulating film. When the pressure on both sides is not consistent, it causes displacement of the measuring diaphragm, which is proportional to the pressure difference. Therefore, the capacitance on both sides is unequal. Through oscillation and demodulation, it is converted into a signal proportional to the pressure.