【作者】 尚春艳；

【导师】 杨彦杰；

【作者基本信息】 河北工业大学 ， 电机与电器， 2004， 硕士

【摘要】 水位计广泛应用于水利、石油、化工、冶金、电力等领域的自动检测和控制系统中。本文设计的智能水位计是吸收了国内外最新智能化仪表的设计经验，采用工业控制单片机，集水位采集、存储、显示及远程联网于一体，适用于各种液位及闸门开度的测量。它具有高精度、高可靠性、多功能和智能化等特点。 针对研制任务的要求，课题期间研制了下位机系统硬件和软件，开发了上位机监控软件，其中所作的具体工作包括：测量原理的研究和在系统中的实现，在本次设计中用三种方法来进行水位测量，分别是旋转编码器法、液位压力传感器法和可变电阻器法；主控芯片的选择，我们选用了高集成度的混合信号系统级芯片C8051F021；实现了信号的采集和处理，包括信号的转换和在单片机内的运算；高集成度16位模数转换芯片AD7705在系统中的应用，我们完成了它与单片机的接口设计及程序编制任务；精确时钟芯片DS1302在系统中的应用，在此，我们实现了用单片机的I／O口与DS1302的连接和在软件中对时序的模拟，该芯片的应用给整台仪器提供了时间基准，方便了仪器的使用；另外，针对研制任务的要求，还给系统加上了一路4～20mA模拟信号电流环的输出电路来提供系统监测，该部分的实现是通过采用AD421芯片来完成的，本设计中完成了AD421与单片机的SPI接口任务，协调了它与AD7705芯片和单片机共同构成的SPI总线系统的关系，并完成了程序设计；与上位机的通信接口设计，该部分通过两种方法实现：RS232通信方式和RS485通信方式；系统设计方面还包括报警电路设计、操作键盘设计、电源监控电路设计、电压基准电路的设计。在硬件设计的基础上，对系统进行了软件设计，软件部分包括下位机单片机程序的设计和上位机监控软件的设计。在软硬件充分结合的情况下，实现了系统设计要求，很好地解决了以往的水位计中存在的问题，达到了高精度水位测量仪器的各项标准。更多还原

【Abstract】 Water-level meter is generally used in the automatic supervision and control system of water conservancy, rock oil, chemical industry, metallurgy, electric power etc. Based on the abundant experience of domestic and abroad intelligent meters, the meter presented in the paper is designed via advanced microchip, which integrates the functions such as data collection and storage, display and remote communication and can be used in various fluid level and strobe opening scale measurements.According to the request of this subject, we have developed the system hardware and software for the slave device and the inspection software running on the PC. In this paper all of the followings is illustrated detailedly, such as the research on the principles of measurement and its realization, Three means of water-level measurement that are separately based on photo electricity coder, pressure sensor and potentiometer; Selection of the microchip, We choose an advanced integrated SOC(System on Chip) microchip C8051F021 as the main controller; Realization of signal sampling, processing and its conversion in the MCU; Application of highprecision 16 bits ADC CMOS chip--AD7705 in our system, designing its interface with themicrochip and relevant program; Using a trickle charge timekeeping chip DS1302 in the system which can provide time norm and designing of its i/o interface and program; Additionally, a 4~ 20mA current output channel to provide system check-up using AD421. In the system, AD421, AD7705 and the microchip compose SPI bus; To communicate with the master PC, here we use two ways which are separately RS232 and RS485; Moreover, there are alarm unit, keyboard unit, power supply inspection unit and voltage norm providing unit in the system. Based on the hardware, we have finished software in the slave device and supervision software on the master PC. With all of the above, this water-level meter has satisfied all the request of system, settled many problems ever existed in the previous ones and attained high preciseness as a good meter.更多还原