Many people usually mistake pressure transmitters and pressure sensors for the same, which represent sensors. In fact, they are very different.
The electric measuring instrument in the pressure measuring instrument is called pressure sensor. Pressure sensors are generally composed of elastic sensors and displacement sensors.
1. The function of elastic sensitive element is to make the measured pressure act on a certain area and convert it into displacement or strain, and then convert it into electrical signal related to pressure by displacement sensitive element or strain gauge. Sometimes the functions of these two elements are integrated, such as the solid-state pressure sensor in the piezoresistive sensor.
2. Pressure is an important process parameter in the consumption process and aerospace, aviation and national defense industries. It not only needs to stop rapid and dynamic measurement, but also digitally display and record the measurement results. The automation of large oil refineries, chemical plants, power plants and iron and steel plants also needs to transmit the pressure parameters at long intervals, and request to convert the pressure and other parameters, such as temperature, flow and viscosity, into digital signals and send them to the computer.
3. Pressure sensor is a kind of sensor which is highly valued and developed rapidly. The development trend of pressure sensor is to further improve the dynamic response speed, accuracy and reliability, and complete digitization and intelligence. Common pressure sensors include capacitive pressure sensor, variable reluctance pressure sensor, hall pressure sensor, optical fiber pressure sensor, resonant pressure sensor, etc.
There are many kinds of transmitters. The transmitters used in industrial control instruments mainly include temperature transmitter, pressure transmitter, flow transmitter, current transmitter, voltage transmitter and so on.
1. The transmitter is equivalent to a signal amplifier. The AC220V transmitter we use provides dc10v bridge voltage to the sensor, then receives the feedback signal, amplifies and outputs a 0V ~ 10V voltage or current signal. There are also small transmitters of DC24V, which are almost as large as sensors and sometimes installed together. Generally speaking, the transmitter supplies power to the sensor and amplifies the signal. The sensor only collects signals, such as strain gauge, which changes the displacement signal into resistance signal. Of course, there are sensors without power supply, such as thermocouples and piezoelectric ceramics, which are usually used.
2. We have used different types of pressure sensors, but the transmitter has hardly been replaced. The pressure sensor detects the pressure signal, generally referring to the primary meter. The pressure transmitter combines the primary meter and the secondary meter, and converts the detected signal into standard 4-20, 0-20 Ma or 0-5V, 0-10V signals, You can understand this vividly: the sensor "feels" the transmitted signal, and the transmitter not only feels it, but also "becomes" a standard signal and then "sends" it out.
Pressure sensor generally refers to the sensitive element that converts the changed pressure signal into the corresponding changed resistance signal or capacitance signal, such as piezoresistive element, piezocapacitive element, etc. Pressure transmitter generally refers to a complete set of circuit unit for measuring pressure composed of pressure-sensitive elements and conditioning circuit. Generally, it can directly output standard voltage signal or current signal in linear relationship with pressure for direct collection by instruments, PLC, acquisition card and other equipment.
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Post time: Sep-08-2021