4~20ma傳感器電流信號(hào)并行數(shù)據(jù)傳送電路設(shè)計(jì)-畢業(yè)論文

1、摘要摘要工業(yè)上利用傳感器測(cè)量到的各種非電量信號(hào)通常都需要轉(zhuǎn)換成標(biāo)準(zhǔn)模擬量電信號(hào)才能傳輸?shù)綆装倜淄獾目刂剖一蝻@示設(shè)備上。由于電壓信號(hào)遠(yuǎn)距離傳送時(shí)易受干擾，且會(huì)產(chǎn)生壓降，所以遠(yuǎn)距離傳送時(shí)通常采用電流信號(hào)。其中使用最廣泛的是4~20mA標(biāo)準(zhǔn)模擬量電流信號(hào)，可以使用雙絞線進(jìn)行遠(yuǎn)距離傳送。隨著微處理器的應(yīng)用推廣，現(xiàn)場(chǎng)測(cè)量越來(lái)越多地采用智能化儀表。為了使現(xiàn)場(chǎng)智能儀表和控制室系統(tǒng)間進(jìn)行數(shù)字通信（可以實(shí)現(xiàn)對(duì)測(cè)量系統(tǒng)進(jìn)行在線調(diào)整、數(shù)據(jù)讀取等功能），需要在

2、此4~20mA模擬信號(hào)上疊加上數(shù)字信號(hào)進(jìn)行雙向的數(shù)字通信，以共用通道的方式來(lái)傳送數(shù)字信號(hào)。本設(shè)計(jì)利用4~20mA電流源芯片AD421和調(diào)制解調(diào)器芯片A5191HRT實(shí)現(xiàn)這一雙向通信過程，半雙工工作，信息接收與處理接口以MSP430F149單片機(jī)為例，如用其它的微處理器將之替換即可。本文系統(tǒng)的介紹了實(shí)現(xiàn)此過程的電路設(shè)計(jì)過程，包括單片機(jī)的最小系統(tǒng)的設(shè)計(jì)，4~20mA電流信號(hào)傳送電路的設(shè)計(jì)，加載FSK信號(hào)的電路設(shè)計(jì)，以及實(shí)現(xiàn)FSK信號(hào)反向傳送

3、的電路的設(shè)計(jì)。關(guān)鍵詞：關(guān)鍵詞：4~20mA4~20mA電流信號(hào)電流信號(hào)FSKFSK信號(hào)信號(hào)數(shù)據(jù)雙向傳送數(shù)據(jù)雙向傳送半雙工工作方式半雙工工作方式目錄i目錄第一章第一章緒論緒論...................................................................................................................11.1設(shè)計(jì)背景...........

4、................................................................................................11.2研究?jī)?nèi)容與框架...............................................................................................1第二章第二章4~20mA電流傳送通

5、道電路設(shè)計(jì)電流傳送通道電路設(shè)計(jì)....................................................................32.14~20mA電流概述............................................................................................32.2環(huán)路供電型4~20mADAC—AD421.......

6、........................................................32.2.1AD421概述............................................................................................32.2.2AD421電路描述............................................

7、........................................52.3AD421外圍電路連接圖設(shè)計(jì)..........................................................................72.4AD421數(shù)字接口電路設(shè)計(jì).......................................................................

8、.......82.54~20mA電流接收端電路設(shè)計(jì)........................................................................9第三章第三章FSK信號(hào)加載電路設(shè)計(jì)信號(hào)加載電路設(shè)計(jì)................................................................................113.1HART協(xié)議概述...

9、..........................................................................................113.2FSK（頻移鍵控）信號(hào)概述..........................................................................123.3HART調(diào)制解調(diào)器A5191HRT................

10、.....................................................133.4A5191HRT外圍電路設(shè)計(jì).............................................................................173.5MSP430F149控制A5191HRT電路圖設(shè)計(jì).........................................

11、........173.64~20mA傳送通道上加載FSK信號(hào)電路設(shè)計(jì).............................................18第四章第四章半雙工工作方式及交流驅(qū)動(dòng)電路實(shí)現(xiàn)半雙工工作方式及交流驅(qū)動(dòng)電路實(shí)現(xiàn).........................................................214.1電路半雙工工作方式實(shí)現(xiàn)...........................

12、..................................................214.2交流電流驅(qū)動(dòng)電路設(shè)計(jì).................................................................................24第五章第五章MSP430單片機(jī)最小系統(tǒng)設(shè)計(jì)單片機(jī)最小系統(tǒng)設(shè)計(jì)..........................................

13、............................255.1MSP430F149單片機(jī)概述..............................................................................255.2MSP430F149的最小系統(tǒng)設(shè)計(jì)......................................................................26

14、5.2.1電源.......................................................................................................275.2.2復(fù)位電路...............................................................................................275.