基于單片機(jī)的壓力測控系統(tǒng)

目錄

0  前言 1
1  緒論 2
1.1設(shè)計意義 2
1.2設(shè)計相關(guān)問題現(xiàn)狀研究 2
1.2.1單片機(jī)的發(fā)展歷史 2
1.2.2 單片機(jī)發(fā)展趨勢 3
1.2.3 無線數(shù)據(jù)通信 4
1.2.4 壓力傳感器發(fā)展趨勢 4
1.3液壓支架發(fā)展動態(tài) 4
2  硬件部分設(shè)計 8
2.1總體設(shè)計 8
2.2單片機(jī)選擇 9
2.3壓力變送器結(jié)構(gòu) 10
2.3.1液壓支架對變送器的要求 10
2.3.2 PA-8壓阻式OEM硅壓力傳感器 13
2.4  信號調(diào)理電路設(shè)計 14
2.4.1  信號放大電路 15
2.4.2  濾波電路 18
2.5  A/D轉(zhuǎn)換器 20
2.6  自動復(fù)位電路 21
2.7  本安電源與本安電路 22
2.8  通信接口 24
2.8.1  MAX485 24
2.8.2  RS-485標(biāo)準(zhǔn)優(yōu)點(diǎn) 24
2.8.3 通信系統(tǒng)的構(gòu)成 25
2.8.4 通信協(xié)議 27
3  軟件設(shè)計 28
3.1主程序設(shè)計 28
3.2串行口通訊程序 29
3.3A/D轉(zhuǎn)換程序 31
3.4 濾波子程序設(shè)計 32
3.4.1  數(shù)字濾波 32
3.4.2  中值濾波法 33
3.4.3  算術(shù)平均濾波法 33
3.4.4  加權(quán)平均濾波 33
3.4.5  復(fù)合濾波 34
3.5  顯示子程序設(shè)計 36
4  技術(shù)經(jīng)濟(jì)分析 39
5  總結(jié) 41
致謝 42
參考文獻(xiàn) 43
附錄A   譯文 45
附錄Ｂ  外文原文 50

 
摘要

本設(shè)計選用單片機(jī)AT89C51做為控制核心，通過壓力傳感器和檢測比較器測得氣缸內(nèi)壓力, 通過單片機(jī)實(shí)現(xiàn)自動控制。確定了采樣頻率，采集回的壓力信號通過A/D轉(zhuǎn)換電路轉(zhuǎn)換為數(shù)字信號分析了數(shù)字濾波的方法把中值濾波和算術(shù)平均值濾波兩種方法結(jié)合起來對壓力信號進(jìn)行復(fù)合濾波，通過標(biāo)度變換程序把數(shù)字量轉(zhuǎn)換為易于顯示和分析的壓力值,在對于超出設(shè)定的壓力值輸出控制電磁閥。
本課題所設(shè)計的壓力變送器與一般變送器比較，有兩大特點(diǎn):由于變送器的工作環(huán)境有沖擊載荷和爆炸性氣體存在，所以在結(jié)構(gòu)上要求設(shè)計一阻尼孔，以減小對傳感器的沖擊;在電路上要求設(shè)計為本安電路，保證工作安全。
本論文闡述了國內(nèi)外壓力變送器的發(fā)展?fàn)顩r及它的組成和工作原理，分析了液壓支架的工作環(huán)境和壓力變化情況，對壓力變送器提出了技術(shù)要求。比較了液壓支架用壓力傳感器的種類和性能，根據(jù)壓力傳感器的選用原則，設(shè)計了一壓阻式壓力變送器。論述了壓阻式壓力傳感器的結(jié)構(gòu)，研究了PA-8壓力傳感器的供電方式，通過對所用元器件進(jìn)行選型，設(shè)計了完整的恒流源供電電路。，
關(guān)鍵詞：單片機(jī)；壓力變送器；測控系統(tǒng)

Abstract

Data collection circuit of analog signals is researched，singlechip AT89C51 is chose to be control core，sampling frequency is determined，pressure signal coming from sampling/keeping  circuit is transformed to be digital signal through A/D convertion  circuit，method of digital filter is analized，median filter and arithmetical mean filter are band together to be complex filter for filtering pressure signal，digital is converted to  Pressure value which is prone to display and analyse through csale conversion program。
The pressure transmitter and its measurement system of the paper have high precision and rapid response speed，requirement suggested by support is meet，so，it is fit for monitoring pressure of support。
Momentum of development，composition and operating principle of the foreign and national transmitter are represent，work environment of support and variation of pressure are analized，technical requirement of pressure transmitter is put forward。Classification and property of hydraumatic pressure sensor are compared，according to the preferred principle of pressure sensor，piezoresistive pressure transmitter is designed。Struction of piezoresistive pressure sensor is discussed，method of current supply of PA-8 pressure sensor is researched，though the lectotype of device，constant-current source circuit is designed。
KEY WORDS: DSP; Pressure transmitte; Switch Module