Small Digital Pressure Sensors With High Precision And Data Acquisition System

With the rapid development of space technology,the requirement of measurement system is higher then before.As an important part of the measurement system,the measureement of pressure is not only limited to the some key parts,but also the stress condition of the entire aircraft surface,which greatly increases the number of applications of sensors.The traditional pressure sensors and their data acquisition systems are unable to adapt to the new requirements.The small digital pressure sensors with high precision and data acquisition system designed in this paper include a number of sensors and converter.One sensor converter could loads up to 44 sensors at the same time,while controlling then to collect pressure data.The data are summarized and send to the control system through the RS-422 bus.The pressure sensing element of the system selects the 24-bit isolation membrane digital output pressure sensor 89 BSD,and the communication driver circuit is constituted by the I2 C bus extension chip P82B715 to realize the communication between the sensor and the converter at 5 meters away.The RS-422 interface chip adopts the MAX3490 of singlechannel transceiver.At the same time,the ground test bench of the system is designed,and the host computer software is used for data processing and display.According to the task indicators,this paper analysis the function at first,formulated the overall design scheme,then illustrates the key technology of the system,solved the problem of the sensor miniaturization and long distance communication.Then each module of the hardware circuit design was introduced,the control flow of digital pressure sensor and multiple sensors parallel editorial logic were illustrated,system communication protocol and the PC software of the ground test bench is designed.Finally,the main hardware circuit and the overall system are tested,the problems appeared in debugging process are solved,and the measurement precision of the system is further improved through the calibrationThe test results show that the small digital pressure sensors with high precision and data acquisition system designed in this paper have completed the design task with good performance and high practical value.