分类主要是为了更好地满足客户要求，其结构不同，所用膜盒也不同。 The classification of pressure transmitters is mainly to better meet customer requirements. The structure of different pressure transmitters is different.
The pressure transmitter is also known as the universal gauge pressure transmitter. One side is connected to the atmosphere and the other side is connected to the measured pressure. For pressure measurement of pipes, boilers, etc.
Different pressure transmitters are connected to different pressures on both sides, and the liquid level is measured according to the pressure difference, and the pipe flow is measured with the orifice plate.
An absolute pressure transmitter is evacuated on one side, and the pressure on the other side is absolute pressure, which is suitable for absolute pressure occasions.
工作原理及特点： Working principle and characteristics of pressure transmitter :
The piezoresistive pressure transmitter uses a piezoresistive sensitive core, which is small in size, high in sensitivity and good in stability. Its characteristics are mainly reflected in its sensitive core.
As the name implies, the principle of a piezoresistive transmitter is that the resistance change of a sensitive core is compressed, and then the resistance change is converted into a standard signal output through an amplification circuit.
There are currently three types of piezoresistive cores
1. Principle of silicon diffusion
Structure: Particles are implanted on a silicon wafer to form a piezoresistor in the form of a Wheatstone bridge.
Features: high sensitivity and high precision, suitable for measuring 1kpa ～ 40Mpa,
Strong overpressure capability, good impact resistance
It is divided into 2 types with isolation diaphragm and non-isolation diaphragm. Non-isolation diaphragm can only measure clean gas. The isolation diaphragm is a soft diaphragm, which is not suitable for measuring viscous media.
Large temperature drift
2. Strain principle:
Construction: Combines a varistor in the form of a Wheatstone bridge with a strained material (usually stainless steel)
Features: Overload capacity, strong anti-shock pressure, low sensitivity, suitable for measuring high-range ranges above 500kpa,
Up to 500Mpa
Small temperature drift
High strength, vibration resistance, not easy to damage
High range (above 1Mpa) good linearity and high accuracy
Hard diaphragm structure, suitable for measuring various media compatible with strained materials
3. Principle of ceramic piezoresistance:
Structure: Sintering the varistor with ceramic in the form of a Wheatstone bridge
Features: The overload capacity is lower than the strain principle, and the impact pressure is poor.
High sensitivity, suitable for measuring high range over 50kpa, the highest range is 40Mpa
Corrosion resistance, wide temperature range
In general, piezoresistive transmitters are characterized by small size, good accuracy and stability, and temperature drift can be reduced to a small degree through circuit compensation (or built-in compensation of sensors)
量程需要根据测量范围的不同选型。 The main drawback is that the pressure overload capacity is generally only three times the range, which is not convenient for range migration. Generally, the transmitter range needs to be selected according to the different measurement ranges.