单片机的薄膜谐振式水位传感器的高度测量用频率计的设计与制作.pdf

摘 要 本文介绍了一种以单片机(AT89C51)为核心与薄膜谐振式水位传感器配套 用的液位高度测量用频率计的设计与制作。还介绍了谐振式水位传感器的新型传 感原理,传感器的结构,数字振荡电路的特点，阐述了水位与频率的对应关系。薄 膜谐振式水位传感器 内置三点式水位传感器振荡电路，该振荡电路的固有频率随 水位的变化而变化，通过检测该振荡电路的固有频率来判定水位的高低。 该频率计直接利用单片机内部的计数器对薄膜谐振式水位传感器的频率脉冲 信号进行计数，然后利用单片机的定时功能实现对频率的检测，最后通过 LED 动态显示电路显示数值。在设计中应用了单片机的运算和控制功能，满足测量的 精度要求，该频率测量仪器测量误差小于 ±10Hz 测频性能稳定可靠，可单独 用，也可方便嵌入系统中。 该频率计具有结构简单、价格低、精度高、操作简单、并且降低产品的成 本,有利于新产品的设计与研制、等特点。随着单片机应用技术的发展，越来越 多的测量仪器都采用单片机作为系统进行设计，应用单片机进行系统设计时系统 结构简单、控制方便、硬件设计需要外围器件较少，软件设计可采用汇编语言编 程，汇编语言具有编程方便、运算效率高、占用内存少等优点。 关键词： 液位检测；频率测量；传感器；单片机 Abstract This paper presents the design and fabrication of a Microprocessor (AT89C51)based film resonant with the water level sensor supporting the use of the liquid level measurement frequencymeter.The principle of new resonator water level sensor is mainly introduced.The internal structure of this Sensor and the characteristic of numeral oscillation circuit are analyze dindetails.There ationship between frequently and water level is expounded.Films resonant water level sensor built-in three-point level sensor oscillation circuit.The oscillator circuit changed with the natural frequency of the water level. By detecting the oscillation circuit natural frequency to determine the level of water. The frequencymeter use the Microprocessor internal counter to counting the film resonant frequency of the water level sensor pulse,then Microprocessor regular function to achieve frequency testing, final adoption of LED display circuit dynamic numerical show.Application of the design of the 89C51 operation and control functions ，Meet the required precision measurement ，The error of the frequency measurement instrument is less than ±10Hz ，Performance measurement frequency stability and re