The Design Of Data Acquisition System Of The Hall Experiment

Physical experiments play an important role in training student's scientific thinking method and scientific research capability. We can improve the teaching quality by introducing computer techniques to physical experiments. In this paper, as an experimental unit we complete the betterment of experimental equipment of the Hall experiment and design the data acquisition system of Hall experiment by combining physical experiment with computer and intelligent instrument techniques.This paper mainly complete four aspects of the work: (1) Selecting the system scheme. By argumentation, we select the scheme of distributed data acquisition system, which includes one upper computer and many lower computers. Lower computers acquire experiment datas and upload them to upper computer, the upper computer completes the handling and storage of experiment datas. They communicate each other by the RS-232 or the RS-485 bus. (2) Completing the design of systematic hardware, including signal processing, A/D convert, serial communication, display and storage etc. In order to simplify the hardware structure, we use the I2C bus in the design of storage, display and keyboard circuits. (3) Completing the design of system software, including lower computer software and upper computer software. We design the all-purpose simulant software wrap of the I2C bus in the lower computer software. Multi thread is used in the communication programme of upper computer. (4) We research the question of system accuracy. The error of Hall Element is analysed and the compensative method is provided; this paper makes the theoretical analysis of errors producing by the instrument amplifier and A/D converter. We adopt the technology of digital filter and linearization implementing by the Neural Network method.This system has been applied in the experimental teaching successfully. Its success can provide directive meaning to the betterment of other physical experiments.