Design And Implementation Of Multi-channel High-precision Data Acquisition Device

In flight tests,it is usually necessary to accurately collect multiple physical quantity signals in the cabin to monitor the working status of the various systems in the cabin,but the electromagnetic environment in the cabin of the aircraft is complex and full of various noises,which is very easy to cause the accuracy of signal acquisition Influence,so how to collect sensor signals with multiple channels and various signal forms with high precision becomes the focus of the design.In this design,the hardware circuit and software control logic are designed according to the modular design idea,which achieves the purpose of high-precision acquisition.Firstly,the parameters of each type of sensor to be collected are analyzed and the overall design scheme of the data collection device is put forward.Then the noise and error that affect the acquisition accuracy are modeled and quantitatively described.Combined with the analysis of the influence factors of the acquisition accuracy and the characteristics of each sensor signal,a low noise signal conditioning circuit was designed.In order to reduce the influence of power supply noise on the acquisition accuracy,a method of combining switching power supply with linear power supply is designed to achieve the purpose of circuit design of low-noise power supply.At the same time,the sampling quantization circuit and Ethernet interface circuit are designed to ensure the reliable acquisition and transmission of sensor signals.In terms of logic design,in order to reduce the quantization noise and pulse interference generated during the acquisition of sensor signals,oversampling technology and de-extremum average filtering algorithm are adopted in the sampling quantization control logic to reduce the influence of noise and pulse on the acquisition accuracy.Aiming at the problem that the filtering order of the hardware filter circuit is low and the high-frequency noise cannot be completely filtered out,a high-order FIR filter is added in the software logic design to attenuate the high-frequency noise doped in the sensor signal.Due to the problem that the sampling frequency of each type of sensor is different and the data amount varies greatly,the frame of the data of different types of sensors is designed and transmitted by Ethernet TCP protocol to ensure the reliability of the data transmission.Finally,the closed-loop test system is built to test the data acquisition accuracy and reliability of data transmission of the data acquisition device,and the test results are analyzed to verify that the data acquisition device can meet the requirements of the design index.