About the measurement principle of pressure transmitters in industrial automation control systems that you don't know

In modern industrial automation control systems, pressure transmitters are used in the section where pressure monitoring is required to collect signals or serve as feedback signals to monitor and adjust the process, so as to achieve safe and orderly management and control. But here, there is the real measurement principle of industrial automation control system and pressure transmitter that you don't know. Now let's analyze the principle analysis of the actual situation:

Because of the different characteristics and application conditions of the process medium, we must combine the measurement principle of the pressure transmitter and the on-site usage to analyze the cause of the pressure transmitter failure, find practical and effective solutions, and achieve from selection to installation, From application to maintenance rationality, efficient problem solving.

The measurement principle of the pressure transmitter is not the focus of this article, only a brief introduction to the working principle and classification of the pressure transmitter is given here. Simply put, the pressure transmitter uses sensors, demodulators, current detectors, amplifiers, etc. to convert the pressure change signal into a standardized signal that the controller can read. The current signal of 4~20mA DC is mainly used, and there are also 1~5 VDC voltage signal or communication signal, etc. The types of pressure transmitters can be simply divided into:

(1) Piezoresistive transmitters are mainly composed of semiconductor piezoresistive materials under pressure. Due to the piezoresistive effect of the piezoresistor, the resistivity changes, so that the bridge generates a voltage signal proportional to the pressure. This can measure changes in pressure.

(2) Capacitive transmitter, which uses the measuring diaphragm and the electrodes on the insulating sheets on both sides to form a capacitor. The two pressures of the measured medium pass through the high and low voltage chambers and act on the isolation diaphragms on both sides of the sensitive element. The diaphragm will be displaced according to the pressure, and the capacitance on both sides will change. This capacitance change will be converted into a readable signal by the controller through oscillation and demodulation.

(3) Inductive pressure transmitters are generally composed of pointer pressure gauges and electronic remote transmission components. When the pressure causes the spring tube of the pressure gauge to deform and displace, the iron core in the inductance coil will also be displaced, and the inductance will change, and this change value will be converted into a DC current/voltage signal.

(4) The strain-type pressure transmitter is also measured by converting pressure into resistance value. The two strain gauges are glued to the strain tube along the axial and radial directions with special adhesives. When the strain tube is under pressure, the shape of the resistance strain gauge will change, which will affect the resistance value, and the pressure. The difference between the resistive measurement principle is that the strain transmitter will cause the shape of the strained material to change. In fact, in different application conditions, there are other pressure transmitters with various measurement methods, which will not be described here.

The above is the key analysis of the situation. Do you have any ideas about the situation now? The above is the measurement principle and classification of pressure transmitters in industrial automation control systems that Xiaobian has compiled for you. For more information, please log in to Weihai Kunke* for inquiries at any time. Weihai Kunke Flow Meter Co., Ltd. (www.kunkeandao.com)