【作者】 缪欣；

【导师】 唐慧强；

【作者基本信息】 南京信息工程大学 ， 系统分析与集成， 2007， 硕士

【摘要】 物位测量在工业生产中占有很重要的地位，而电容式物位测量仪表以其结构简单、工作可靠、维护方便的优点在物位测量领域中占有重要的地位。但电容式物位测量仪表在测量导电粘性物料时存在挂料误差，使电容式物位测量仪表的应用范围受到限制。另外，物位计一般采用RS-232，RS485串行通信接口，而串行通信的数据信号存在通信双方的共地干扰。在一些复杂的工业场合下有线通信更存在着传输电缆引起测量误差，化学腐蚀，安装困难等问题。因此为解决这些问题而设计了一种运用射频导纳原理和无线通信接口的新型物位计。本文对射频导纳测量原理进行了详细论述及推导，给出了消除挂料影响、测量真实物位的方法。然后详细论述了射频导纳测量原理的电路实现，包括电源电路，复位电路，激励信号发生电路，信号检波电路，滤波电路以及信号采集电路。此外对无线通信接口的设计作了论述。最后本文对系统的软件设计进行了论述，尤其在无线通信协议的制定进行了重点的介绍。本文采用嵌入式模块的设计理念，所设计的物位计不仅改进了传统电容式物位计测量导电粘性物体时由于挂料而造成的虚假物位，同时采用无线通信接口与上位机相连，能够明显减少误差和恶劣的工业环境影响，具有高实时性，高精度，适应范围广等特点。更多还原

【Abstract】 The level measurement is very important in the industry. With its construction simply, working dependability, supporting convenience, the level instrument with capacitance is very important in level field. However, the level instrument with capacitance will produce error resulted in hang material when it is used in conductive and sticky material,so the applying of level instrument with capacitance is limited. In addition, the general level instrument communicate with RS232 or RS485, which exist interference resulted in thecommon earth in communication, and on the complicated industrial environment, there are some problems in communication: measurement error, chemeical transformation, hard installation and so on. Accordingly, a new kind of level instrument based on RF principles and wireless communication is designed for solving these problems in this paper.RF admittance level measuring principle is discussed in detail and the method of eliminating the hang material’s effect and getting the true level is given in this paper, the next, the design of hardware circuit for the RF principle such as power circuit, reset circuit, the circuit of signal generator, signal detection circuit, the filter circuit, the circuit of signal collection, the interface of wireless communication. Finally the software is given, particularly the design of agreement in wireless communication in this paper.The embedded design is given in this paper, and the instrument not only improves traditional capacitive level instrument in deceitful level resulted in hang material, but also obviously reduces error and influence in bad industry environment. The instrument has the characteristic of realtime, high accuracy, and can be widely used.更多还原