Classification, principles and characteristics of pressure transmitters

May.2022 12

Details

Generally speaking, a pressure transmitter mainly consists of three parts: a load cell sensor (also called a pressure sensor), a measurement circuit, and a process connection. It can convert physical pressure parameters such as gas and liquid sensed by the load cell sensor into standard electrical signals (such as 4~20mADC, etc.) to provide secondary instruments such as indicating alarms, recorders, and regulators for measurement and indication. and process regulation.

Pressure transmitters can be divided into three types according to the measurement range: general pressure transmitters (0.001MPa ~ 35MPa), micro differential pressure transmitters (0 ~ 1.5kPa), and negative pressure transmitters; from the perspective of accuracy, because Our standard accuracy is 0.5%. So in recent years, it can be divided into high-precision pressure transmitters (0.1% or 0.2% or 0.075%) and general pressure transmitters (0.5%)

The function of pressure transmitter

The pressure transmitter transmits the pressure signal to the electronic device, and then displays the pressure on the computer.

Principle of pressure transmitter:

Convert the mechanical signal of pressure such as water pressure into an electronic signal such as current (4-20mA). Pressure has a linear relationship with the voltage or current, generally proportional to the relationship. Therefore, the voltage or current output by the transmitter increases with the pressure. The increase leads to a relationship between pressure and voltage or current.

The two pressures of the measured medium of the pressure transmitter pass into the high and low pressure chambers. The pressure in the low pressure chamber adopts atmospheric pressure or vacuum, which acts on the isolation diaphragms on both sides of the δ element (ie, the sensitive element). Through the isolation diaphragm and The filling fluid in the element is transferred to both sides of the measuring diaphragm. The pressure transmitter is a capacitor composed of a measuring diaphragm and electrodes on both sides of the insulating sheet. When the pressure on both sides is inconsistent, the measuring diaphragm is displaced, and the displacement is proportional to the pressure difference, so the capacitance on both sides is unequal. Through the oscillation and demodulation link, it is converted into a signal proportional to the pressure.

Features of pressure transmitters

1) It can be used in a wide range of measured media. It can measure oil, water and pastes compatible with 316 stainless steel and 304 stainless steel. It has certain anti-corrosion capabilities.

2) High accuracy, high stability, imported original sensors, good linearity and high temperature stability.

3) Small size, light weight, easy to install, debug and use

4) Stainless steel fully enclosed shell, good waterproof.

5) The pressure sensor directly senses the measured liquid level pressure and is not affected by medium bubbling and sedimentation.

Rosemount Smart Transmitter Related Features