基于LM3S1138智能RLC测试仪的设计

发布时间：2018-08-17 12:12

【摘要】：随着电子行业的蓬勃发展，人们对电子元器件的精度要求越来越高。一款高精度、低成本、便携式的电阻电容电感测试仪拥有巨大的应用空间。本文在参考传统测试仪器的基础上，结合现代微处理器应用，设计了一款满足要求的RLC测试仪。在测试方法选择上，本文详细比较了交流电桥法、L-C谐振法和伏安法，最终选择伏安法来设计RLC智能测试仪。设计的仪器中拥有信号发生器，能发出一系列频率可调的交流波形，通过振荡电路，将电感值L（或者电容C）变成相对应的频率信号f，利用单片机LM3S1138的内部计数器进行采样，记算产生方波的脉冲频率，通过一系列的程序运算比对和信号反馈调节，单片机自动调整合适的量程和数值，，也可以通过键盘直接输入选择，计算出检测的电感值或者电容值，最终将结果通过串行口传到移位寄存器，在LCD屏上显示出来。本文首先介绍了国内外检测仪表的发展历程，分析讨论了国内外检测仪器的现状和智能仪表的发展趋势，然后介绍了电阻、电感和电容的一些基本参数和常用的测量方法，通过方案比较确定本课题的检测原理。其中着重介绍以LM3S1138为主控制器构成系统的内部结构和扩展功能，并对以MAX038为主要芯片的智能信号发生器的信号发生电路和控制电路详细说明。并且重点研究了该系统的程序流程和实际应用，包括频率测量、RLC测量、人机通信和AD/DA等模块。最后使用设计完成的测试仪测量具体的电阻、电感和电容值，记录结果并对误差进行了相应的分析，结果表明设计的RLC测试仪基本达到了预期效果。
[Abstract]:With the rapid development of electronic industry, the precision of electronic components is required more and more. A high-precision, low-cost, portable resistive capacitance inductance tester has huge application space. Based on the reference of traditional testing instruments and the application of modern microprocessor, this paper designs a RLC tester which meets the requirements. In the selection of test methods, this paper compares the AC bridge method with the voltammetry method in detail, and finally chooses the voltammetry method to design the RLC intelligent tester. The designed instrument has a signal generator, which can send out a series of frequency adjustable AC waveforms. By oscillating circuit, the inductance L (or capacitance C) is changed into the corresponding frequency signal f, and the internal counter of single chip computer LM3S1138 is used to sample. The pulse frequency that produces square waves is recorded. Through a series of program comparisons and signal feedback adjustments, the single chip microcomputer automatically adjusts the appropriate range and values. It can also be selected directly by the keyboard to calculate the measured inductance or capacitance value. Finally, the result is transmitted to the shift register through the serial port and displayed on the LCD screen. This paper first introduces the development history of domestic and foreign measuring instruments, analyzes and discusses the present situation of domestic and international testing instruments and the development trend of intelligent instruments, then introduces some basic parameters and common measuring methods of resistance, inductance and capacitance. The detection principle of this subject is determined by comparing the schemes. The internal structure and extended function of the system composed of LM3S1138 as main controller are emphatically introduced, and the signal generation circuit and control circuit of intelligent signal generator based on MAX038 are described in detail. The program flow and practical application of the system are mainly studied, including frequency measurement, man-machine communication and AD/DA modules. Finally, the resistance, inductance and capacitance are measured with the designed instrument, and the results are recorded and the error is analyzed accordingly. The results show that the designed RLC tester basically achieves the desired results.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TM930.2;TP368.12

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