水處理過程微機監控系統的研究
概述
純(chun)凈(jing)水(shui)是特殊(shu)行(xing)(xing)業至關重(zhong)要的(de)(de)(de)生產物資,如電廠鍋爐(lu)用水(shui)等。純(chun)凈(jing)水(shui)在(zai)水(shui)質、水(shui)壓、流量(liang)等方(fang)面的(de)(de)(de)要求是非常嚴格的(de)(de)(de)。目(mu)前我國很多水(shui)凈(jing)化(hua)(hua)的(de)(de)(de)自動(dong)化(hua)(hua)程(cheng)度(du)還(huan)不(bu)(bu)是很高,對(dui)(dui)供(gong)出的(de)(de)(de)純(chun)凈(jing)水(shui)水(shui)質、水(shui)壓、流量(liang)等數(shu)據(ju)的(de)(de)(de)采集和監(jian)測(ce)還(huan)只是人(ren)工(gong)的(de)(de)(de)定時(shi)巡檢,不(bu)(bu)能實(shi)時(shi)準確地進(jin)行(xing)(xing)監(jian)控,嚴重(zhong)影響(xiang)供(gong)水(shui)的(de)(de)(de)質量(liang),而且,若出現了(le)質量(liang)問(wen)題也只能根據(ju)人(ren)工(gong)抄表(biao)(biao)的(de)(de)(de)數(shu)據(ju)進(jin)行(xing)(xing)核(he)對(dui)(dui),由于(yu)(yu)存在(zai)人(ren)為的(de)(de)(de)因素,對(dui)(dui)及(ji)時(shi)發(fa)現問(wen)題和解決問(wen)題不(bu)(bu)利;同(tong)時(shi),人(ren)工(gong)抄表(biao)(biao)的(de)(de)(de)數(shu)據(ju)不(bu)(bu)利于(yu)(yu)數(shu)據(ju)的(de)(de)(de)及(ji)時(shi)匯總和形成報表(biao)(biao),不(bu)(bu)便(bian)于(yu)(yu)管理人(ren)員和質量(liang)控制人(ren)員根據(ju)報表(biao)(biao)進(jin)行(xing)(xing)決策。如果對(dui)(dui)整個水(shui)處理實(shi)行(xing)(xing)全(quan)過(guo)程(cheng)微機監(jian)控,對(dui)(dui)各個參數(shu)進(jin)行(xing)(xing)24ｈ實(shi)時(shi)監(jian)控,那么有利于(yu)(yu)形成報表(biao)(biao)以(yi)供(gong)決策。綜上所述,在(zai)水(shui)凈(jing)化(hua)(hua)系統實(shi)行(xing)(xing)全(quan)過(guo)程(cheng)實(shi)時(shi)監(jian)控是很有必(bi)要的(de)(de)(de)。
1 微機監控系統的(de)工(gong)作原(yuan)理
整(zheng)個(ge)微機(ji)監(jian)控(kong)(kong)(kong)系(xi)統的框(kuang)圖(tu)如(ru)圖(tu)1所(suo)示。微機(ji)監(jian)控(kong)(kong)(kong)系(xi)統須采(cai)集和監(jian)測的輸入(ru)信(xin)號共計有512個(ge),包(bao)(bao)括:原水(shui)量(liang)、純水(shui)量(liang),各個(ge)采(cai)樣點的瞬時流(liu)(liu)量(liang)、電(dian)(dian)導率、電(dian)(dian)壓(ya)、電(dian)(dian)流(liu)(liu)、閥的開度、壓(ya)力、溫度、電(dian)(dian)耗、水(shui)位(wei)、過載信(xin)號、控(kong)(kong)(kong)制(zhi)反(fan)饋信(xin)號等(deng),通(tong)過各種傳感元件(jian)、一次儀表或其他方式進入(ru)系(xi)統。控(kong)(kong)(kong)制(zhi)輸出信(xin)號共有192個(ge),包(bao)(bao)括電(dian)(dian)機(ji)、電(dian)(dian)磁閥控(kong)(kong)(kong)制(zhi)、電(dian)(dian)動閥控(kong)(kong)(kong)制(zhi)等(deng)。
輸(shu)入(ru)(ru)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)從(cong)(cong)總體上(shang)可分(fen)為(wei)(wei)三類:開關量(liang)(liang)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)、模擬量(liang)(liang)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)、脈(mo)(mo)沖(chong)(chong)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)。開關量(liang)(liang)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)包(bao)括(kuo)由浮球式水(shui)位(wei)(wei)(wei)儀(yi)接入(ru)(ru)的(de)(de)(de)水(shui)位(wei)(wei)(wei)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)、由反(fan)饋觸點(dian)接入(ru)(ru)的(de)(de)(de)控制(zhi)反(fan)饋信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)。模擬信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)包(bao)括(kuo)由液位(wei)(wei)(wei)傳感器(qi)接入(ru)(ru)的(de)(de)(de)液位(wei)(wei)(wei)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)、由電(dian)(dian)(dian)導(dao)率(lv)表(biao)接入(ru)(ru)的(de)(de)(de)電(dian)(dian)(dian)導(dao)率(lv)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao);由互感器(qi)接入(ru)(ru)的(de)(de)(de)電(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)流信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao);由位(wei)(wei)(wei)置(zhi)感應(ying)器(qi)接入(ru)(ru)的(de)(de)(de)閥(fa)度信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)等(deng)。以上(shang)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)均為(wei)(wei)(4～20ｍＡ)電(dian)(dian)(dian)流信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)。脈(mo)(mo)沖(chong)(chong)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)包(bao)括(kuo)由脈(mo)(mo)沖(chong)(chong)流量(liang)(liang)計接入(ru)(ru)的(de)(de)(de)水(shui)量(liang)(liang)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao),由脈(mo)(mo)沖(chong)(chong)式電(dian)(dian)(dian)度表(biao)接入(ru)(ru)的(de)(de)(de)電(dian)(dian)(dian)耗信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)等(deng)。其邏(luo)輯(ji)"0"電(dian)(dian)(dian)平為(wei)(wei)1Ｖ以下,邏(luo)輯(ji)"1"電(dian)(dian)(dian)平為(wei)(wei)3.5Ｖ～30Ｖ。輸(shu)出(chu)(chu)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)包(bao)括(kuo)19臺水(shui)泵(beng)、加藥泵(beng)的(de)(de)(de)驅運控制(zhi),其電(dian)(dian)(dian)機功率(lv)范圍從(cong)(cong)0.5ｋＷ～37ｋＷ不等(deng)。電(dian)(dian)(dian)磁(ci)閥(fa)和電(dian)(dian)(dian)動閥(fa)門功率(lv)都(dou)很(hen)小。輸(shu)出(chu)(chu)信(xin)(xin)(xin)(xin)(xin)(xin)號(hao)(hao)(hao)(hao)均以220Ｖ進行控制(zhi)。
現場信號(hao)的分(fen)布較(jiao)復雜,相(xiang)互距離集中(zhong)在泵房、水池、處理車間等幾個工(gong)作(zuo)現場,因(yin)此(ci)在系(xi)統(tong)控制方式和策(ce)略上要(yao)加以考(kao)慮。
在微機(ji)(ji)監控(kong)(kong)(kong)系(xi)統(見圖1)中采(cai)用(yong)(yong)一級2臺(tai)工控(kong)(kong)(kong)機(ji)(ji)控(kong)(kong)(kong)制(zhi),以(yi)提(ti)高可(ke)(ke)靠性,采(cai)用(yong)(yong)施耐(nai)德公(gong)司(si)的Ｑｕａｎｔｕｍ系(xi)列可(ke)(ke)編程(cheng)序控(kong)(kong)(kong)制(zhi)器(qi)(ＰＬＣ)作為下(xia)位控(kong)(kong)(kong)制(zhi)機(ji)(ji),研華公(gong)司(si)的ＩＰＣ610Ｐ工控(kong)(kong)(kong)機(ji)(ji)為主(zhu)(zhu)控(kong)(kong)(kong)計算機(ji)(ji),監測數據(ju)(ju)的提(ti)取(qu)采(cai)用(yong)(yong)Ｍｏｄｉｃｏｎ的數據(ju)(ju)采(cai)集模塊,并以(yi)Ｍｏｄｂｕｓ方式連(lian)接,以(yi)提(ti)高數據(ju)(ju)的可(ke)(ke)靠性和減少布線(xian)。主(zhu)(zhu)控(kong)(kong)(kong)計算機(ji)(ji)之間(jian)、工控(kong)(kong)(kong)機(ji)(ji)與ＰＬＣ之間(jian)通過以(yi)太網連(lian)接,操(cao)作人員可(ke)(ke)察看工作情況(kuang)和查閱(yue)報表。
2 系統的硬件設計
系(xi)統(tong)的硬件設計與選(xuan)取直接關系(xi)到(dao)系(xi)統(tong)的性能。由于(yu)系(xi)統(tong)對可靠性、抗干(gan)擾性等方面的要求較高(gao),本(ben)方案在硬件設計中(zhong)采用的方法和措施主(zhu)要有:
1)主控(kong)(kong)計(ji)算(suan)(suan)機是整個系統的核心,負責(ze)收集、處理、顯示各個數據(ju)監測(ce)模(mo)塊(kuai)通(tong)過Ｍｏｄｂｕｓ網絡傳過來的數據(ju),并根據(ju)處理結果(guo)做出相應的控(kong)(kong)制(zhi)(zhi),在本系統中采(cai)用研華(hua)ＩＰＣ610Ｐ工業控(kong)(kong)制(zhi)(zhi)計(ji)算(suan)(suan)機,采(cai)用ＰⅢ1ＧＣＰＵ,通(tong)過2個以太(tai)網接口分(fen)別與交換機、可(ke)編程序控(kong)(kong)制(zhi)(zhi)器及各個模(mo)塊(kuai)進行通(tong)訊,具(ju)有防(fang)撞擊、防(fang)震動(dong)、耐高溫等特(te)性,其(qi)抗干(gan)擾性、可(ke)靠性都能達到(dao)系統要(yao)求(qiu)。
2)可(ke)(ke)編程控(kong)(kong)制(zhi)器是系(xi)統(tong)控(kong)(kong)制(zhi)的(de)(de)(de)主要部分,接受來自主控(kong)(kong)計算(suan)機(ji)(ji)的(de)(de)(de)指令,并(bing)且通過程序邏(luo)輯(ji)(ji)向外發出控(kong)(kong)制(zhi)信號(hao),控(kong)(kong)制(zhi)外面的(de)(de)(de)執行(xing)機(ji)(ji)構,同時把執行(xing)機(ji)(ji)構的(de)(de)(de)反饋信號(hao)以及另(ling)外的(de)(de)(de)輸入(ru)信號(hao)狀態傳給主計算(suan)機(ji)(ji),供主控(kong)(kong)計算(suan)機(ji)(ji)處理。本系(xi)統(tong)采用Ｑｕａ ｎｔｕｍ系(xi)列可(ke)(ke)編程控(kong)(kong)制(zhi)器,其存儲器可(ke)(ke)達512Ｋ字(zi)以上,最多(duo)可(ke)(ke)擴展到3個(ge)(ge)(ge)機(ji)(ji)架,30個(ge)(ge)(ge)Ｉ Ｏ單元,梯形邏(luo)輯(ji)(ji)解算(suan)時間為0.3～1.4μｓ,Ｉ Ｏ的(de)(de)(de)刷(shua)新時間為0.7ｍｓ,配有1個(ge)(ge)(ge)ＣＰＵ模塊,16個(ge)(ge)(ge)Ｉ Ｏ單元,1個(ge)(ge)(ge)以太(tai)網通訊模塊,其輸出均(jun)可(ke)(ke)采用220Ｖ電壓,可(ke)(ke)大(da)大(da)簡化控(kong)(kong)制(zhi)設計,各個(ge)(ge)(ge)輸入(ru)輸出可(ke)(ke)加入(ru)保(bao)險管進行(xing)短路保(bao)護。
3)數據監測(ce)模(mo)塊(kuai)集中進(jin)行數據采(cai)集和監測(ce),并通過Ｍｏｄｂｕｓ網絡傳給主(zhu)控ＣＰＵ,使得(de)控制和線路簡(jian)單,維修(xiu)方便。在本(ben)系統中采(cai)用(yong)(yong)(yong)Ｍｏｄｉｃｏｎ的輸(shu)入輸(shu)出(chu)模(mo)塊(kuai)140ＡＣ系列,它(ta)是(shi)一種專用(yong)(yong)(yong)的模(mo)擬量模(mo)塊(kuai),具(ju)有(you)雙纜(lan)接(jie)口的設備,可進(jin)行軟件配(pei)置和校準(zhun),采(cai)用(yong)(yong)(yong)Ｍｏｄｂｕｓ傳輸(shu)標準(zhun),Ｍｏｄｂｕｓ是(shi)一個(ge)事實上的工業(ye)標準(zhun)主(zhu) 從協(xie)議,現分(fen)別介紹如(ru)下:
ａ)簡單且安裝方便
ＭｏｄｂｕｓＰｌｕｓ雙絞(jiao)線(xian)電(dian)纜和Ｍｏｄｂｕｓ連接器(qi)系統使安(an)裝輕而(er)易舉(ju)(ju),作(zuo)為一種自舉(ju)(ju)網(wang)絡,Ｍｏｄｂ ｕｓＰｌｕｓ是真(zhen)正的(de)即插即用網(wang)絡。
ｂ)Ｍｏｄｂｕｓ跨系列連接
ＭｏｄｂｕｓＰｌｕｓ使(shi)所(suo)有Ｍｏｄｉｃｏｎ模塊式(shi)控(kong)制器之(zhi)間可相互連(lian)接,同時可與Ｍｏｄｃｏｎｎｅｃｔ合作伙伴生產(chan)的各種產(chan)品連(lian)接。
ｃ)高性能
以可預測(ce)的和確定的方式每秒傳遞20,000位(wei)至寄存(cun)器,并且(qie)包括全局數據(ju)和對等(deng)數據(ju)表,使通訊建立(li)和初始化簡便易(yi)行。
ｄ)維護容易
診(zhen)斷程(cheng)序和ＬＥＤ正常 故障(zhang)狀態指示可使現場人員(yuan)很(hen)快(kuai)修復網(wang)絡故障(zhang)。
ｅ)通訊編程容易
無(wu)論是簡單的984梯形邏輯ＭＳＴＲ指令或Ｃｏｎｃｅｐｔ中(zhong)的ＩＥＳ1131等(deng)功能,均(jun)能較(jiao)容易應用(yong)(yong)于通(tong)訊和(he)(he)綜合(he)網(wang)絡診(zhen)斷等(deng)事件的初始化。主(zhu)計算機(ji)用(yong)(yong)ＮＥＴＢＩＯＳ可(ke)兼容軟件庫實現ＭｏｄｂｕｓＰｌｕｓ,該庫可(ke)在主(zhu)應用(yong)(yong)程序中(zhong)調用(yong)(yong)。每個ＭｏｄｂｕｓＰｌｕｓ主(zhu)機(ji)接口都(dou)配有合(he)適的軟件庫,提供(gong)給所有主(zhu)要(yao)(yao)的平臺和(he)(he)主(zhu)要(yao)(yao)的操作系統。其他器件如網(wang)絡、中(zhong)繼器等(deng)使(shi)網(wang)絡的設計與執行更靈活。網(wang)絡使(shi)單個ＭｏｄｂｕｓＰｌｕｓ網(wang)絡能夠連在一起,從而使(shi)總的可(ke)尋址節點的數超(chao)過16,000,000。雙絞線(xian)中(zhong)繼器可(ke)使(shi)通(tong)訊距離長達1820ｍ左右。
主控計算機與(yu)可編程控制器之間(jian)采(cai)用(yong)以太網接口(kou)通(tong)訊協(xie)議,與(yu)各個模(mo)擬量(liang)采(cai)集模(mo)塊(kuai)之間(jian)采(cai)用(yong)ＭｏｄｂｕｓＰｌｕｓ通(tong)訊協(xie)議。ＭｏｄｂｕｓＰｌｕｓ協(xie)議是特別為滿足工(gong)業控制要求設計的(de)(de)主 從標準(zhun)。具有(you)通(tong)訊距離長、傳送速(su)率高、連(lian)線(xian)少、連(lian)接容易的(de)(de)特點,是工(gong)業上(shang)使用(yong)最廣(guang)泛的(de)(de)雙向有(you)補償(chang)傳輸線(xian)標準(zhun)。
3 系統的軟件設計
系統軟(ruan)件(jian)采用(yong)(yong)組態(tai)軟(ruan)件(jian),采用(yong)(yong)ＧＥ公司的(de)(de)(de)(de)ＩＦ ｉｘ2.6ＣＰｌｕｓＳＣＡＤＡＰＡＣＫ900Ｒ Ｔ工(gong)(gong)控組態(tai)軟(ruan)件(jian),安全(quan)(quan)能力(li)包(bao)括使(shi)(shi)用(yong)(yong)跟蹤數(shu)據輸入和報(bao)警確(que)認的(de)(de)(de)(de)電(dian)子(zi)簽名、一個(ge)可(ke)(ke)以(yi)使(shi)(shi)ＩＦｉｘ安全(quan)(quan)特(te)性(xing)與操作系統安全(quan)(quan)特(te)性(xing)保持同步的(de)(de)(de)(de)功能強大的(de)(de)(de)(de)工(gong)(gong)具(ju)、報(bao)警ＯＤＢＣ服(fu)務升級和報(bao)警一覽對(dui)象(xiang)中(zhong)(zhong)(zhong)新增的(de)(de)(de)(de)報(bao)警確(que)認行(xing)為;對(dui)于(yu)ＩＦｉｘ畫(hua)面(mian)(mian)(mian),創(chuang)建畫(hua)面(mian)(mian)(mian)向(xiang)導(dao)可(ke)(ke)以(yi)無縫地創(chuang)建多(duo)畫(hua)面(mian)(mian)(mian)配置,或者(zhe)使(shi)(shi)用(yong)(yong)一個(ge)已經存在(zai)畫(hua)面(mian)(mian)(mian)的(de)(de)(de)(de)尺寸(cun);新增的(de)(de)(de)(de)數(shu)據鏈(lian)接(jie)郵(you)戳(chuo)標記有助于(yu)控制數(shu)據鏈(lian)接(jie)的(de)(de)(de)(de)尺寸(cun)和位置;多(duo)對(dui)象(xiang)創(chuang)建模式具(ju)有創(chuang)建特(te)定對(dui)象(xiang)多(duo)個(ge)實例的(de)(de)(de)(de)能力(li);基(ji)本(ben)動(dong)畫(hua)對(dui)話框允(yun)許在(zai)同一位置訪問若干個(ge)常用(yong)(yong)的(de)(de)(de)(de)動(dong)畫(hua)專家;ＩｎｆｏＡｇ ｅｎｔ圖(tu)符可(ke)(ke)以(yi)使(shi)(shi)畫(hua)面(mian)(mian)(mian)中(zhong)(zhong)(zhong)包(bao)含Ｗｅｂ網頁;交叉引用(yong)(yong)工(gong)(gong)具(ju)可(ke)(ke)以(yi)方(fang)便地確(que)定在(zai)畫(hua)面(mian)(mian)(mian)中(zhong)(zhong)(zhong)被使(shi)(shi)用(yong)(yong)的(de)(de)(de)(de)標簽和使(shi)(shi)用(yong)(yong)標簽的(de)(de)(de)(de)畫(hua)面(mian)(mian)(mian);編輯圖(tu)符向(xiang)導(dao)和圖(tu)表(biao)組向(xiang)導(dao)作為工(gong)(gong)具(ju)可(ke)(ke)以(yi)下(xia)載,目前已經集成(cheng)在(zai)ＩＦｉｘ中(zhong)(zhong)(zhong);虛擬鍵盤(pan)可(ke)(ke)以(yi)用(yong)(yong)于(yu)觸摸(mo)屏環(huan)境(jing)以(yi)及使(shi)(shi)用(yong)(yong)鼠標輸入密碼或數(shu)據的(de)(de)(de)(de)情況;新增的(de)(de)(de)(de)ＳＭ2模擬驅(qu)動(dong)器提供(gong)用(yong)(yong)于(yu)測試用(yong)(yong)途的(de)(de)(de)(de)地址矩陣。系統的(de)(de)(de)(de)流(liu)程如(ru)圖(tu)2。
系(xi)統(tong)啟(qi)(qi)動后進(jin)(jin)行(xing)初始化操作,以(yi)確(que)保各個(ge)部分的(de)(de)(de)正常(chang)工(gong)作,隨后系(xi)統(tong)啟(qi)(qi)動主(zhu)線(xian)程(cheng)(cheng)和(he)各個(ge)通訊(xun)線(xian)程(cheng)(cheng),通訊(xun)線(xian)程(cheng)(cheng)負責與可(ke)編(bian)程(cheng)(cheng)控(kong)制(zhi)(zhi)信號器的(de)(de)(de)通訊(xun),它實(shi)時(shi)地將外面的(de)(de)(de)輸(shu)入信號與各種模擬(ni)量傳入計算機,同時(shi)將計算機的(de)(de)(de)輸(shu)出命令和(he)輸(shu)出模擬(ni)量傳給可(ke)編(bian)程(cheng)(cheng)控(kong)制(zhi)(zhi)器,去控(kong)制(zhi)(zhi)外面的(de)(de)(de)執行(xing)機構;控(kong)制(zhi)(zhi)數(shu)(shu)據(ju)采集(ji)模塊的(de)(de)(de)數(shu)(shu)據(ju)通過以(yi)太網實(shi)時(shi)地傳入計算機;主(zhu)控(kong)線(xian)程(cheng)(cheng)負責將來自可(ke)編(bian)程(cheng)(cheng)和(he)數(shu)(shu)據(ju)采集(ji)模塊的(de)(de)(de)數(shu)(shu)據(ju)進(jin)(jin)行(xing)處理(li)(li),然后根據(ju)處理(li)(li)結果進(jin)(jin)行(xing)輸(shu)出控(kong)制(zhi)(zhi)、數(shu)(shu)據(ju)顯示(shi)、故障報警,并形成(cheng)歷史曲線(xian)和(he)數(shu)(shu)據(ju)報表(biao),供(gong)管理(li)(li)人員查閱和(he)參考(kao)。
4 運行狀況與分析
本系(xi)統在(zai)電廠的(de)(de)水凈化(hua)過程系(xi)統中投入實際運(yun)行,使(shi)用(yong)以太網進行遠程數據(ju)(ju)采集,運(yun)行狀況良好(hao),避免了以前的(de)(de)人工抄表、人工控制所帶來的(de)(de)一系(xi)列問題,提(ti)高了勞動(dong)生產力,并且為管理(li)人員(yuan)提(ti)供了可靠(kao)的(de)(de)數據(ju)(ju)依據(ju)(ju)。方(fang)案采取的(de)(de)有效(xiao)措施(shi)有:
1)主(zhu)控計算機在現場條件下(xia)應具備可(ke)靠(kao)接地,要減(jian)少(shao)干擾;
2)通訊電(dian)纜應(ying)采(cai)用屏(ping)蔽(bi)線;
3)以太(tai)網絡過(guo)長時應加入中繼器,并(bing)注意網絡終(zhong)端匹配的(de)選擇。
5 小結
1)監控系統的設計(ji)應充分考(kao)慮系統要求(qiu)和成(cheng)本(ben)。在本(ben)系統中(zhong),若各個(ge)設備獨立地進行(xing)數(shu)據采(cai)集和傳輸必將引起成(cheng)本(ben)上(shang)升,而(er)且可(ke)靠性也(ye)不(bu)易得到保證。
2)要采(cai)取合(he)理的控制(zhi)策略和控制(zhi)結構。本系統(tong)根據現場特點(dian),采(cai)用一級(ji)控制(zhi)結構、集(ji)散式控制(zhi)系統(tong)和Ｍｏｄｂｕｓ總(zong)線方(fang)式,性能(neng)優良且降低了(le)成(cheng)本。
3)系統在遠(yuan)程現(xian)場控制的安全等方面(mian)還需要進(jin)一步完善。
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