基于單片機的超聲波液位測量系統的設計

電子機電論文編號:JD635  附任務書,答辯PPT,原理圖,論文字數:14810,頁數:39

目  錄

摘要…………………………………………………………………………………Ⅰ
Abstract……………………………………………………………………………Ⅱ
緒論……………………………………………………………………………………1
第1章 超聲波液位測量儀的硬件設計………………………………………………3
     1.1 超聲波液位測量儀的總體設計…………………………………………3
        1.1.1  超聲波測距原理 ………………………………………………3
        1.1.2  超聲波液位測量儀硬件的結構…………………………………4
1.2 單片機與各部分電路的接口…………………………………………5
     1.3 超聲波發射及驅動電路……………………………………………………6
1.4 超聲波接收和過零檢驗電路 …………………………………………6
1.5 溫度采集和V/F轉換電路………………………………………………7
 1.5.1 信號采集電路…………………………………………………………7
1.5.2 放大電路與線性調整電路……………………………………………9
1.5.3  V/F轉換電路   …………………………………………………… 9
1.5.4  PT100分度表 …………………………………………………………11
     1.6 顯示電路及鍵盤輸入…………………………………………………………11

1.7 直流供電電路的設計………………………………………………………13
第2章  PC機與單片機之間的通信………………………………………………………14
     2.1 PC機與單片機通信系統總框架……………………………………………14
     2.2 串口通信網絡硬件構成…………………………………………………15
         2.2.1 RS-485通信總線簡介…………………………………………………15
         2.2.2 通信接口設計方案……………………………………………………16
         2.2.3 串口的通信協議 ………………………………………………………17
第3章  誤差分析…………………………………………………………………………20
     3.1  超聲波回波聲強的影響………………………………………………………20
  3.2   超聲波波束入射角的影響………………………………………………20
  3.3   超聲波傳播速度的影響 ……………………………………………………21
     3.4   提高測試精度的措施…………………………………………………………22
     3.5   數據誤差 ……………………………………………………………………23
     3.6   抗干擾…………………………………………………………………………23
第4章  超聲波液位測量儀的軟件設計 …………………………………………………24
     4.1  主程序模塊 …………………………………………………………………24
     4.2  串行口中斷程序模塊 ………………………………………………………25
結論 ………………………………………………………………………………………26
致謝……………………………………………………………………………………27
參考文獻 …………………………………………………………………………………28
附錄（一）………………………………………………………………………………29
附錄（二）………………………………………………………………………………37
附錄（三）………………………………………………………………………………39

摘 要

根據聲波在空氣中傳播反射原理, 以超聲波換能器為接口部件, 應用單片機技術對超聲波在空氣中的傳播時間進行測量, 從而設計了一套超聲波液位檢測系統。從而實現無接觸式測距。系統硬件由系統由AT89C4051 單片機、超聲波發射電路、超聲波接收放大電路、環境溫度采集電路及顯示電路組成。并對其檢測原理、方法以及系統軟件結構作了詳細介紹, 在超聲波測距中進行溫度補償和對時間計算的誤差修正, 討論了提高測距精度的方法, 并提出了干擾噪聲的處理方法。對產生測量誤差的原因進行了分析, 并提出了解決的途徑和方法。

關鍵詞:超聲波測距; 聲速; 單片機；液位；溫度補償

Meter Based on Ultrasonic to Measure
the Liquid-level

Abstract
According to an up in the air dissemination  glint principle, with a wave changes the ability machine for connect a people's parts, apply a machine technique to carry on the diagraph to an up in the air dissemination time, thus designed an examination system. Thus carry out to have no contact the type measures to be apart from the system hardware is been shot the electric circuit, a wave by a machine of AT89C4051, a wave by the system to receive to enlarge the electric circuit, the environment temperature to collect the electric circuit and the manifestation electric circuits to constitute the Combine the as the to the it's the examined the principle, the method the and the system the  software the structures the to the make the detailed introduction, the carry the on the temperature the repair the and the compute to the time the in the a wave the measuring the to the be apart the from the of the error margin revise, the discuss the exaltation to the measure the method of the be apart the from the accuracy, and put forward the processing method of the interference noise voice. Measured the reason of the error margin to carry on the analysis to the creation, and the path and the method that definitely put forward the understanding.

Key words: ultrasonic ranging; velocity of sound; microprocessor；Liquid-level; temperature compensate