摘要
高精度AD转换、海量数据存储与便携技术，是目前数据采集研究领域一个比较关注的热点，这些技术的实现和应用，可以很好的解决传统数据采集中精度低、数据不易保存等一些问题。
本课题来源于太原理工大学应用力学研究所《高精度移动数据采集装置》项目，该项目是设计一台可用于施工现场的高精度、U盘存储与便携式数据采集装置。
本文在查阅了国内外文献的基础上，研究了目前市场上便携式数据采集装置，给出了一种基于嵌入式操作系统μC／OS-Ⅱ、U盘存储与16位AD转换精度的便携式数据采集装置的设计方案。
本套数据采集装置由主控单元与数据采集单元两部分构成，主控单元具有液晶显示、实时时钟、环境温度检测、数据存储功能，通过RS-485接口可与上位机进行数据通信；数据采集单元可采集6路模拟量信号、8路开关量信号，与主控单元用SPI接口进行数据传输。
数据采集单元采用TI半导体公司的两片16位MSP430F425来实现16位精度的数据采集与处理，该单片机内部的SD16模块将外部模拟电压信号转换成16位数字量，同时进行数据处理和开关量的采集。为保证模拟输入信号在AD转换最佳线性范围内，还设计了量程转换电路。MSP430F425单片机采集的数据通过SPI总线传输到主控单元。
主控单元采用菲利浦半导体公司的32位ARM内核LPC2132单片机，其数据处理能力和丰富的片内资源可满足数据采集装置的功能和性能需要。设计的U盘存储电路中，LPC2132单片机通过USB接口芯片CH375，把采集到的数据以FAT16的文件格式写入U盘，PC机可通过读取U盘对信号数据进行二次分析与处理。U盘存储数据的设计是本装置便携特性的体现。为了方便用户的观察与操作，设计了液晶显示、键盘等电路，并给出了详细的电路原理图。
为了实现采集装置功能，设计了主控单元与数据采集单元的程序。数据采集单元的程序包括AD转换功能、数据处理、开关量采集与SPI通信功能；主控单元软件设计采用了嵌入式操作系统任务设计思想，首先将μC／OS-Ⅱ移植到LPC2132单片机中，并具体设计和实现了该装置功能的各个任务，μC／OS-Ⅱ的应用使数据采集具有更好的实时性，同时方便了系统的扩展和升级。
试验电路验证了主要设计原理的可行性与合理性，为高精度移动数据采集装置的产品设计提供了依据。
论文最后介绍了本文的主要工作，说明了论文的特点和意义，同时指出了系统设计的不足和改进。
The technique of portability, mass volume of data storage and high precision of A/D conversion is becoming a hot spot in data acquisition field at present. The implementation and application of this technology would solve problems such as low precision, data volatility, that can't be done by traditional data acquisition method.
The subject originated from a project of High Precision and Portable Data Acquisition Device of Applied Mechanics Research Institute of TYUT. The subject was to design a portable device with high A/D precision and USB storage which can sample signals from application field.
On the dissertation a solution of data acquisition device based on the embedded operation system, mass storage via USB and high precision of A/D conversion was given after massive references was consulted and popular related devices on the market investigated.
This device consists of two parts, of which the host can function as data-storage, real-time display of LCD and ambient temperature inspection, communication with upper PC through RS485 interface while acquisition part can implement multi-channel data acquiring, including 6 analog signals and 8 switch signals, data transferring to the host through SPI bus.
In the acquisition part, two MSP430F425 microprocessors from TI Company are employed to undertake data acquiring and 16-bit A/D conversion. for the sake of the best A/D conversion linearity of the input, a scale auto-switch circuit was made. The results of acquisition are transferred to the host through SPI bus.
The host adopts 32 bits, ARM core LPC2132 as microcontroller, which is produced by PHILIPS Semiconductor Corporation. It has strong data processing ability and abundant resources in chip to meet the needs of data acquisition. In the circuit of data storage, LPC2132 writes data to U disk in the format of FAT16 file system by USB interface chip CH375. PC could have data further analysis and process by reading U disk. Saving data at U disk characterizes the mobility of the device. The LCD interface and keyboard circuit were devised and the schematics shown in detail to ease the observation and operation of customers.
The software design of the acquisition part and the host were done to fulfill the device's function. The programs of acquisition part includes A/D conversion, data processing, switch signal collecting and SPI correspondence. The task management of embedded operation system was introduced to the host software design. The transplant ofμC/OS-II to LPC2132 was completed and specific task and code were done to function the device. The adoption ofμC/OS-II optimizes the real-time attribute and convenience the expansion and promotion the system.
The system was debugged by the test circuits, which proved the designfeasible and reasonable. The experiment would support the design of highprecision mobile data acquisition device.
At the last stage, the dissertation introduced the jobs author did, explainedthe feature and significance. the defects and the improvement was pointed outat the same time.
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