【作者】 付丽玮；

【导师】 王刚；

【作者基本信息】 天津大学 ， 机械制造及其自动化， 2007， 硕士

【摘要】 随着科学技术的发展,超声波技术比较成熟,已广泛应用于众多领域。超声波液位传感器为非接触式测量仪器,用于化工原料液位测量。液位检测有很多种方法,其中超声波测量具有其它方法不可比拟的优点。为满足易燃易爆非接触化学物质液位检测的要求,将单片机、嵌入式系统引入仪表,开发出新型智能超声波传感器,突破了传统传感器的单一功能,实现了自动测量、数据处理、多种输出形式和通讯等。该智能型传感器可进行较为精确的液位测量,设置三种方式与外部通讯.智能型传感器的开发包括硬件和软件两方面。智能型超声波传感器硬件电路由液位信息采集电路、控制单元、人机交互接口电路、与外部通讯接口电路四部分组成。电路采用16位超低功耗微处理器MSP430F449,MSP430F449具有强大的处理能力,FLASH存储器多达60KB,丰富的片上外围模块可节约外围电路的设计,并有方便高效的开发环境。本文选用常用超声波探头,运用温度传感器进行温度补偿,提高了测量的精度。在硬件电路的基础上,用C语言编制了具体实现各个功能的程序。软件由采集液位信息程序、人机交互程序和与外部通讯程序,通讯程序包括异步串行通讯程序﹑4～20mA电流变送程序和以太网数据传输程序组成。本文采用模块化结构的程序设计,便于编写、调试、修改以及功能扩展。实验证明该智能型超声波液位传感器能实现精确的液位测量,通过按键选择进行不同方式的通讯。更多还原

【Abstract】 Along with the development of science and technology, mature ultrasonic technology can be found in many fields. This kind of level sensors is non-contact equipment mainly used for the chemical raw material liquid level measurement .The ultrasonic measurement method has many advantages compared with others which have widely used for many years. To satisfy the requirement of inflammable chemical material non-contact liquid level measurement, intelligent sensor scheme is proposed in this paper.The drawback of conventional sensor with single function is overcomed.This intelligent sensor posseses many outstanding performances: automatic measurement, data processing, various forms of output and data communications.The intelligent sensor is designed to achieve precise measurement and communicate with hose computer and other equitments in three ways. The intelligent sensor is developed of hardware circuits and sortware. Hardware circuits include the circuit of level information collection, control unit, user interface circuits of communication with outside. In circuit, the 16-bite consumption microprosessor, MSP430F449 is chosed as the hard core of the electrical board.The processor is powerful in computing, possesses bigger storage space up to 60KB and is rich in peripherial modules.This makes it easier to develop electrical circuit with more complicated functions.Commonly used ultrasonic probe is adopted as sensing component., the circuit for temperature compensation is carefully designed in order to achieve precise measurement. Based on circuits, the paper selects C laugange to program. The routine is made of liquid level measurement procedure, human-computerinteraction procedure, RS-232 serial communication procedure, Ethernet data transmission procedure and 4~20mA two-wire current transmitte procedure. In this paper, modular software is easy to program, revise and expand.The result of experiment has showed that the intelligent sensor has the ability of precise measurement and communication with outside in three ways through the select of keys.更多还原