Factors affecting the hysteresis characteristics of diffused silicon pressure sensors
Microcyber NCS-PT105ⅡS Profibus DP pressure transmitter with advanced, mature,reliable piezoresistive silicon pressure sensor has been designed meticulously by combining advanced microprocessor technology and digital capacitance measurement technology. The powerful functions and high-speed computing capability of the microprocessor make it have excellent qualifications such as smart, high accuracy, high reliability, stable zero, etc. The LCD module can display physical parameters (e.g. pressure, temperature, etc). It can realize the functions such as zero adjustment, range setting by key-press operation, and it is easy for field testing.
NCS-PT105ⅡS Profibus DP pressure transmitter can measure pressure, differential pressure, liquid level, flow, and other industrial parameters. It can be widely used in the petroleum, chemical, electricity, and metallurgical industries, etc.
With the development of semiconductor technology, the various technical indicators of diffused silicon pressure sensors have been continuously improved, but the inherent unconventional and multi-value corresponding hysteresis and nonlinear characteristics of diffused silicon pressure sensors have limited their measurement accuracy. At present, there are relatively few researches on the hysteresis characteristics of sensors at home and abroad. The existing literature proves that it is not possible to directly use neural networks to model them. The work of most scholars is to treat hysteresis nonlinearity as general nonlinearity, and the results cannot satisfy the compensation. Precision requirements.
The working principle of the diffused silicon pressure sensor is: use the semiconductor plane manufacturing process to make four diffused resistors with the same resistance on the corresponding surface of the silicon cup, and form a Wheatstone bridge through appropriate connection of the diffused resistors. When the diaphragm is under pressure When it is deformed by the action, the resistance on the electric bridge changes accordingly, so that the electric bridge loses its equilibrium state, so the electric signal corresponding to the pressure change is obtained, and the purpose of measuring the pressure is achieved. The resistivity of the semiconductor material changes with the applied force, which is the piezoresistive effect.
1. Raw materials
Any kind of semiconductor material, due to the complexity of its internal organizational structure, will produce micro-strain between the tiny grains after being pressurized by external force. When the external force disappears, the micro-strain disappears, but it does not necessarily return to In the original state, different materials have completely different hysteresis characteristics. To
2. Installation conditions
Surface condition, installation torque, etc. are the biggest influencing factors. It also refers to the installation conditions of the pressure sensor at the use site, such as surface condition, contact area, installation torque, bolt strength, and bearing surface hardness. These influencing factors can sometimes be mistaken for the deterioration of the hysteresis characteristics of the sensor. To
These influencing factors are in direct contact with the sensor, and some other factors seem to have little to do with the sensor itself, but they affect the accuracy of the sensor. Such as the strength of the weighing platform, the firmness of the foundation, dust and water resistance and other factors. These two factors, dust and water, will not have an impact under relatively good maintenance conditions, but they need special attention when used outdoors. The main reason is that the surface of the sensor is corroded, which changes the contact point. Especially for products containing accessories, the rust will cause the accessories and the sensor to "rust" together, which will affect the accuracy. As for the impact of dust on the accuracy of the sensor, experienced users will take appropriate protective measures, such as adding a sealing cover and applying a proper amount of butter on the surface. To
After affecting the hysteresis characteristics of the sensor, thereby affecting the measurement accuracy, it should be avoided as much as possible in the process of manufacturing and actual use to ensure the stable performance of long-term use.
