Capacitive Pressure Transmitter Pressure transmitter is mainly composed of three parts: pressure measuring element sensor, measuring circuit and process connectors. It can transform the physical parameters felt by the pressure measuring element into standard electrical signals to supply secondary instruments such as indicator alarms, recorders, regulators, etc. for measurement, indication and process regulation. Capacitive pressure sensors are those that change the current or voltage by changing the distance between the two plates of high potential and low potential.
The two pressures of the measured medium are passed into the high and low pressure chambers, acting on both sides of the isolation diaphragm of the sensitive element, which is transmitted to both sides of the measurement diaphragm through the isolation diaphragm and the filling liquid inside the element. Capacitive pressure transmitter is composed of a capacitor on each side of the measuring diaphragm and the electrodes on both sides of the insulating piece. When the two sides of the pressure is not consistent, resulting in the measurement of the diaphragm displacement, the displacement and pressure difference is proportional to the two sides of the capacitance is not equal. Through the oscillation and demodulation link, converted into a signal proportional to the pressure. Capacitive pressure transmitter and capacitive absolute pressure transmitter working principle and differential pressure transmitter is the same, the difference is that the low pressure chamber pressure is atmospheric pressure or vacuum.
The capacitive pressure transmitter's A/D converter converts the demodulator's current into a digital signal, the value of which is used by the microprocessor to determine the value of the input pressure, and the microprocessor controls the transmitter's operation. In addition, it performs sensor linearization. Reset the measuring range, engineering unit conversion, damping, open square, sensor trimming and other operations, as well as diagnostics and digital communications. Piezoresistive Pressure Transmitter Monocrystalline Pressure/Differential Pressure Transmitter is used to measure the level, density, and pressure of liquid, gas, or steam, and then convert it into 4~20mA Hart current signal output, also can communicate with HART 375 or BST Modem with each other, and perform parameter setting and process control through them. The difference with the traditional electric contact pressure gauge is that it uses nanometer monocrystalline silicon as the sensor material.
The sensor module is fully welded and has an integral overload diaphragm, a pressure sensor and a temperature sensor. The temperature sensor serves as a reference value for temperature compensation. The positive pressure side of the pressure sensor is connected to the high-pressure chamber of the sensor diaphragm box, and the negative pressure side of the sensor is connected to the low-pressure chamber of the sensor diaphragm box. The pressure is transferred to the silicon chip inside the sensor through the isolation diaphragm and the filling liquid, causing the resistance value of the chip of the pressure sensor to change, which leads to the change of the output voltage of the detection system. The output voltage is proportional to the pressure change, and then converted into a standardized signal output by the adapter unit and amplifier. Monocrystalline silicon piezoresistive pressure sensor principle of operation piezoresistive pressure sensor using monocrystalline silicon piezoresistive effect and composition. The use of monocrystalline silicon chip for the elastic element, in the monocrystalline silicon diaphragm using the integrated circuit process, in the specific direction of the monocrystalline silicon diffusion of a group of equal value resistance. And the resistance is connected to a bridge circuit, monocrystalline silicon wafer placed in the sensor cavity. When the pressure changes, the monocrystalline silicon produces strain, so that the direct diffusion of the strain resistance on the top produces a change proportional to the measured pressure, and then by the bridge circuit to obtain the corresponding voltage output signal.