Many people often mistake pressure transmitters and pressure sensors for the same, they all represent sensors, in fact they are very different.
First, the electric measuring instrument in the pressure measuring instrument is called a pressure sensor. Pressure sensors are generally composed of elastic sensitive elements and displacement sensitive elements.
1. The function of the elastic sensor is to make the measured pressure act on an area and convert it into displacement or strain, and then the displacement sensor or strain gauge converts it into an electrical signal with a certain relationship with the pressure. Sometimes the functions of these two components are integrated, such as solid-state pressure sensors in piezoresistive sensors.
Pressure is an important process parameter in the consumer process and the aerospace, aviation, and defense industries. Not only does it need to stop its rapid dynamic measurement, but it also needs to display and record the measurement results digitally. The automation of large oil refineries, chemical plants, power plants and steel plants also needs to transmit pressure parameters at long intervals, and requests that pressure and other parameters such as temperature, flow, viscosity, etc. be converted into digital signals and sent to the computer.
3. A pressure sensor is a type of sensor that is highly valued and developed rapidly. The development trend of pressure sensors is to further improve the dynamic response speed, accuracy and reliability, and complete digitalization and intelligence. Common pressure sensors are capacitive pressure sensors, variable reluctance pressure sensors, Hall pressure sensors, fiber optic pressure sensors, resonant pressure sensors, and so on.
There are many types of transmitters. The transmitters used in industrial control instruments are mainly temperature transmitters, pressure transmitters, flow transmitters, current transmitters, voltage transmitters and so on.
1. The transmitter is equivalent to a signal amplifier. The AC220V transmitter we use provides the sensor with a DC10V bridge voltage, then receives the feedback signal, amplifies it, and outputs a 0V ~ 10V voltage or current signal. There are also small DC24V transmitters and sensors that are about the same size and are sometimes mounted together. Generally speaking, the transmitter supplies power to the sensor and amplifies the signal. The sensor only collects signals. For example, the strain gauge changes the displacement signal into a resistance signal. Of course, there are also sensors that do not use a power source, such as thermocouples and piezoelectric ceramics, which are usually used.
2. We have used different types of pressure sensors, but the transmitter has not been changed. The pressure sensor detects the pressure signal, which usually refers to the primary meter. The pressure transmitter is a combination of the primary meter and the secondary meter. , And convert the detected signal into a standard 4-20, 0-20 mA or 0-5V, 0-10V signal, you can visually understand this: the sensor is the "feel" of the transmitted, a change The transmitter not only felt it, but also "sent" the standard signal.
A pressure sensor generally refers to a sensitive element that converts a changed pressure signal into a correspondingly changed resistance signal or capacitance signal, such as a piezoresistive element or a piezocapacitive element. The pressure transmitter generally refers to a complete set of circuit units for measuring pressure composed of a pressure-sensitive element and a conditioning circuit. Generally, it can directly output a standard voltage signal or current signal that has a linear relationship with the pressure for meters, plc, acquisition cards, etc. The device collects directly.