【作者】 张锐；

【导师】 宋春宁；

【作者基本信息】 广西大学 ， 检测技术与自动化， 2008， 硕士

【摘要】 澄清中和工序是制糖生产过程中关键工序之一,蔗汁pH值及温度的控制好坏,直接影响糖厂的糖份回收率、产品质量和企业效益。由于制糖生产环境恶劣,生产过程积垢严重,pH值的自动控制技术问题一直没有得到很好地解决,制约了糖厂的经济效益的提高。USB作为一种新的通用串行总线标准,具有较强的纠错能力、速度快、不占用系统资源、方便灵活等特点,应用越来越广泛。本文提出了基于USB通讯的糖厂pH值控制器,该控制器是以微处理器AT91M55800为核心,充分利用AT91M55800微处理器AD、DA资源,外扩是PHILIPS公司的USB芯片PDIUSBD12,采用USB通讯方式,实现pH值数据的采集和控制。在硬件方面,设计了AT91M55800核心板和pH值信号调理扩展板,核心板电路包括AT91M55800微处理器电路、存储器电路、USB通讯接口电路、RS232接口电路、AD接口电路、DA接口电路等,pH值信号调理扩展板主要实现将玻璃电极pH值的微弱信号转换成0-3V的信号。在软件方面,分析了USB通讯的协议,编写了控制器核心板的USB固件程序。采用WDM驱动开发程序DriverStudio实现了PC机的USB驱动,使PC机和pH控制器能够高速高效的进行数据传输。采用PID控制算法,编写了pH值检测控制程序。应用LabVIEW开发了pH值监控软件,实现了通过USB方式来控制三容液位的控制。通过pH值检测实验和三容液位装置控制实验结果表明,本论文设计的基于USB通讯方式的糖厂pH值控制器,具有方便、易用、灵活等优点。运用虚拟仪器技术,实现硬件和软件资源的共享,不仅能进行信号采样和波形显示,还能够对采集的波形数据进行存储、回放和共享。该控制器不仅适用于pH值控制,而且可推广到其他测控领域中使用。更多还原

【Abstract】 Clarification neutralize is the key processes in the sugar production. The control of pH-value and temperature on cane juice directly affects the recovery, product quality and private benefits of sugar. It limits increase of the economic benefit of sugar mill, because of the pool production environment and lots of sediment incrustation of production process. Automatic control of pH-value has not been solved appropriately.As a new generic serial buses standard, the application of USB is more and more widely used. The USB has the characters—strong error correcting capability, fast speed, little system resources, convenience and agility, and so on. This thesis introduces a kind of sugar pH-value controller based on USB communication. The controller uses the microprocessor AT91M55800 as the core and makes the most use of AD-DA resource of AT91M55800. The microprocessor of USB communication is PDIUSBD12. It use USB communication to implement pH-value data gathering and controlling.In hardware, the main board and pH-value signal conditioning board are designed. The main board circuit includes AT91M55800 microprocessor circuit, storage circuit, USB communication interface circuit, RS232 interface circuit, AD interface circuit and DA interface circuit and so on. The pH-value signal conditioning board mainly changes the small voltage of glass electrode pH-value to a 0-3V signal.In software, USB communication protocol is analyzed, and USB firmware program of main board is written. Using WDM drive development tool DriverStudio implements USB driver, it makes PC and pH controller realizing data transfer quickly and effectively. Meanwhile, LabVIEW is used to develop pH-value monitoring software, I realize the control of liquid level through USB mode.The experimental result indicates that the sugar pH-value controller based on USB communication in this paper is convenient, nimble, flexible and so on. The VI technology can achieve the resource sharing of hardware and software. The software of VI can realize signal sampling and waveform display, it also can store, playback and share the waveform data collected. This controller is not only suit for pH-value control, but also can be applied to other Tracking and Controlling field.更多还原