Design Of Low Hysteresis Pressure Sensor And Acquisition System

With the rapid development of Micro-Electro-Mechanical Systems (MEMS), MEMS pressure sensor has become a research hotspot for its small volume, low power consumption, wide span, fast response, easy integration and other advantages.Aiming at the hysteresis error of pressure sensors, a novel method for reducing hysteresis error is proposed. A low hysteresis MEMS capacitive pressure sensor and a data acquisition system are designed. The pressure sensor is composed of three layers of monocrystalline silicon. It can reduce hysteresis error by means of heating the gas in the cavity. ANSYS and FLUENT are used to simulate the sensor structure and the air in the cavity. The response of a pressure sensor at different pressures, the temperature effect on the sensor and the gas flow rate at the through-hole are analyzed. This paper will verify the feasibility of the method of reducing hysteresis error.The data acquisition system consists of a pressure measurement module, a temperature measurement module, a A/D sampling control module, a real-time clock,4-20mA and RS232communication module and a VFD screen display. The temperature signal and pressure signal are measured by a24-bit∑-△ADC conversion chip. The sampled signal is processed by the processor which is based on Cortex-M3. The information is indicated on the VFD screen in real-time and saved to a SD card. It can be transmitted to the receiving terminal with the4-20mA communication module. The system has the advantages of low noise, high precision and fast response speed.