三菱PLC控制系統中電磁干擾的主要來源有哪些？
隨著科學技術的發展，三菱PLC在工業控制中的應用越來越廣泛，三菱PLC控制系統的可靠性直接影響到工業企業的安全生產和經濟運行。三菱PLC在實際應用中的存在著很多種電磁干擾問題，三菱變頻器代理商空簡單介紹三菱PLC控制系統中電磁干擾的主要來源：
1、來自(zi)空間的輻射干擾
空間的(de)(de)輻(fu)(fu)射(she)(she)電(dian)磁場(chang)(chang)（EMI）主要是由電(dian)力網絡、電(dian)氣設(she)備(bei)的(de)(de)暫態過程、雷電(dian)、無線電(dian)廣播、電(dian)視、雷達(da)、高頻感應加熱設(she)備(bei)等(deng)產(chan)(chan)生的(de)(de)，通常稱為(wei)輻(fu)(fu)射(she)(she)干 擾(rao)(rao)，其分布極為(wei)復雜。若三(san)菱PLC系統置(zhi)于射(she)(she)頻場(chang)(chang)內(nei)，就回受(shou)到輻(fu)(fu)射(she)(she)干擾(rao)(rao)，其影響主要通過兩條路(lu)徑；一(yi)是直(zhi)接對三(san)菱PLC內(nei)部(bu)的(de)(de)輻(fu)(fu)射(she)(she)，由電(dian)路(lu)感應產(chan)(chan)生干擾(rao)(rao)； 二(er)是對三(san)菱三(san)菱PLC通信內(nei)網絡的(de)(de)輻(fu)(fu)射(she)(she)，由通信線路(lu)的(de)(de)感應引入干擾(rao)(rao)。輻(fu)(fu)射(she)(she)干擾(rao)(rao)與現(xian)場(chang)(chang)設(she)備(bei)布置(zhi)及設(she)備(bei)所產(chan)(chan)生的(de)(de)電(dian)磁場(chang)(chang)大小(xiao)，特別(bie)是頻率有關，一(yi)般(ban)通過設(she)置(zhi)屏蔽(bi) 電(dian)纜和(he)三(san)菱PLC局(ju)部(bu)屏蔽(bi)及高壓泄放元件進行保護
2、來自系統外引線(xian)的干擾
主(zhu)要通(tong)過(guo)電源和信(xin)號線引入，通(tong)常稱為(wei)傳(chuan)導干(gan)擾。這種干(gan)擾在我(wo)國(guo)工業現場較嚴(yan)重。
3、來自電(dian)源(yuan)的干擾(rao)
實踐證明，因電源引入的(de)干擾造成三菱(ling)PLC控制(zhi)系統故障的(de)情況很多，筆者在某工程調試中遇到過(guo)，后更換隔離(li)性(xing)能更高的(de)三菱(ling)PLC電源，問題才(cai)得到解(jie)決。
三菱(ling)三菱(ling)PLC系統的(de)正常供電(dian)(dian)(dian)電(dian)(dian)(dian)源(yuan)均由(you)電(dian)(dian)(dian)網供電(dian)(dian)(dian)。由(you)于電(dian)(dian)(dian)網覆蓋(gai)范圍廣，將(jiang)受到所有空(kong)間電(dian)(dian)(dian)磁干擾而在線(xian)路上感應(ying)電(dian)(dian)(dian)壓(ya)和電(dian)(dian)(dian)路。尤其是(shi)電(dian)(dian)(dian)網內部的(de)變化， 開關(guan)操作浪涌(yong)、大型(xing)電(dian)(dian)(dian)力設(she)備起停、交(jiao)直流轉動(dong)裝置引起的(de)諧波、電(dian)(dian)(dian)網短路暫態(tai)沖(chong)擊等，都通過輸電(dian)(dian)(dian)線(xian)路到電(dian)(dian)(dian)源(yuan)邊。三菱(ling)三菱(ling)PLC電(dian)(dian)(dian)源(yuan)通常采用隔(ge)離(li)電(dian)(dian)(dian)源(yuan)，但其機 構及制造(zao)工藝因素使其隔(ge)離(li)性并不(bu)理(li)想。實際上，由(you)于分布(bu)參數特別是(shi)分布(bu)電(dian)(dian)(dian)容的(de)存在，絕對(dui)隔(ge)離(li)是(shi)不(bu)可能的(de)。
4、來自信號線引入的干擾
與三(san)菱PLC控(kong)制(zhi)系(xi)(xi)統(tong)連接的(de)(de)各類信(xin)號(hao)(hao)傳(chuan)輸(shu)線，除了傳(chuan)輸(shu)有效(xiao)的(de)(de)各類信(xin)號(hao)(hao)之外(wai)，總會有外(wai)部干(gan)擾(rao)信(xin)號(hao)(hao)侵入。此干(gan)擾(rao)主要有兩種途徑：一(yi)是通(tong)過變(bian)送(song)器或共(gong)用 信(xin)號(hao)(hao)儀表的(de)(de)供(gong)電(dian)電(dian)源串入的(de)(de)電(dian)網干(gan)擾(rao)，這往往被忽略(lve)；二是信(xin)號(hao)(hao)線受空(kong)間電(dian)磁輻射感(gan)應的(de)(de)干(gan)擾(rao)，即信(xin)號(hao)(hao)線上(shang)的(de)(de)外(wai)部感(gan)應干(gan)擾(rao)，這是很嚴(yan)重(zhong)的(de)(de)。由信(xin)號(hao)(hao)引(yin)入干(gan)擾(rao)會引(yin)起(qi) I/O信(xin)號(hao)(hao)工作異常和(he)(he)測量精(jing)度大大降低(di)，嚴(yan)重(zhong)時將(jiang)引(yin)起(qi)元器件損(sun)傷。對于隔(ge)離性能差(cha)的(de)(de)系(xi)(xi)統(tong)，還將(jiang)導致信(xin)號(hao)(hao)間互相干(gan)擾(rao)，引(yin)起(qi)共(gong)地系(xi)(xi)統(tong)總線回流，造成邏輯數據變(bian) 化(hua)、誤動(dong)和(he)(he)死機(ji)。三(san)菱PLC控(kong)制(zhi)系(xi)(xi)統(tong)因(yin)信(xin)號(hao)(hao)引(yin)入干(gan)擾(rao)造成I/O模(mo)件損(sun)壞數相當嚴(yan)重(zhong)，由此引(yin)起(qi)系(xi)(xi)統(tong)故障的(de)(de)情況也很多。
5、來自接地(di)系統混亂時(shi)的干擾
接地(di)(di)(di)(di)(di)是提高電(dian)(dian)(dian)(dian)(dian)子設備電(dian)(dian)(dian)(dian)(dian)磁兼容(rong)(rong)性（EMC）的(de)(de)(de)(de)有效(xiao)手段(duan)之一(yi)。正(zheng)(zheng)確的(de)(de)(de)(de)接地(di)(di)(di)(di)(di)，既能抑制電(dian)(dian)(dian)(dian)(dian)磁干(gan)擾(rao)的(de)(de)(de)(de)影(ying)響(xiang)，又能抑制設備向外(wai)發出(chu)干(gan)擾(rao)；而(er)(er)錯誤(wu)的(de)(de)(de)(de)接地(di)(di)(di)(di)(di)，反而(er)(er)會(hui) 引入(ru)嚴重的(de)(de)(de)(de)干(gan)擾(rao)信號，使(shi)三(san)菱(ling)(ling)PLC系(xi)(xi)(xi)(xi)統(tong)將(jiang)無法正(zheng)(zheng)常(chang)工(gong)作(zuo)。三(san)菱(ling)(ling)PLC控制系(xi)(xi)(xi)(xi)統(tong)的(de)(de)(de)(de)地(di)(di)(di)(di)(di)線(xian)包括(kuo)系(xi)(xi)(xi)(xi)統(tong)地(di)(di)(di)(di)(di)、屏(ping)蔽(bi)(bi)地(di)(di)(di)(di)(di)、交流(liu)地(di)(di)(di)(di)(di)和(he)保護地(di)(di)(di)(di)(di)等(deng)。接地(di)(di)(di)(di)(di)系(xi)(xi)(xi)(xi)統(tong)混(hun)亂(luan)對(dui)(dui)三(san)菱(ling)(ling)PLC系(xi)(xi)(xi)(xi)統(tong)的(de)(de)(de)(de) 干(gan)擾(rao)主要是各個接地(di)(di)(di)(di)(di)點(dian)電(dian)(dian)(dian)(dian)(dian)位(wei)分布(bu)(bu)不(bu)均(jun)，不(bu)同接地(di)(di)(di)(di)(di)點(dian)間存(cun)在(zai)地(di)(di)(di)(di)(di)電(dian)(dian)(dian)(dian)(dian)位(wei)差(cha)，引起(qi)地(di)(di)(di)(di)(di)環(huan)路電(dian)(dian)(dian)(dian)(dian)流(liu)，影(ying)響(xiang)系(xi)(xi)(xi)(xi)統(tong)正(zheng)(zheng)常(chang)工(gong)作(zuo)。例如電(dian)(dian)(dian)(dian)(dian)纜(lan)屏(ping)蔽(bi)(bi)層(ceng)必須一(yi)點(dian)接地(di)(di)(di)(di)(di)，如果電(dian)(dian)(dian)(dian)(dian)纜(lan)屏(ping)蔽(bi)(bi)層(ceng)兩端A、 B都(dou)接地(di)(di)(di)(di)(di)，就存(cun)在(zai)地(di)(di)(di)(di)(di)電(dian)(dian)(dian)(dian)(dian)位(wei)差(cha)，有電(dian)(dian)(dian)(dian)(dian)流(liu)流(liu)過(guo)屏(ping)蔽(bi)(bi)層(ceng)，當發生異(yi)常(chang)狀態(tai)加雷(lei)擊時，地(di)(di)(di)(di)(di)線(xian)電(dian)(dian)(dian)(dian)(dian)流(liu)將(jiang)更(geng)大(da)(da)。 此外(wai)，屏(ping)蔽(bi)(bi)層(ceng)、接地(di)(di)(di)(di)(di)線(xian)和(he)大(da)(da)地(di)(di)(di)(di)(di)有可能構成閉(bi)合(he)環(huan)路，在(zai)變(bian)化磁場 的(de)(de)(de)(de)作(zuo)用下，屏(ping)蔽(bi)(bi)層(ceng)內(nei)有會(hui)出(chu)現感應電(dian)(dian)(dian)(dian)(dian)流(liu)，通(tong)過(guo)屏(ping)蔽(bi)(bi)層(ceng)與(yu)(yu)芯線(xian)之間的(de)(de)(de)(de)耦合(he)，干(gan)擾(rao)信號回(hui)路。若系(xi)(xi)(xi)(xi)統(tong)地(di)(di)(di)(di)(di)與(yu)(yu)其它接地(di)(di)(di)(di)(di)處理混(hun)亂(luan)，所產生的(de)(de)(de)(de)地(di)(di)(di)(di)(di)環(huan)流(liu)可能在(zai)地(di)(di)(di)(di)(di)線(xian)上(shang)產生不(bu)等(deng)電(dian)(dian)(dian)(dian)(dian)位(wei) 分布(bu)(bu)，影(ying)響(xiang)三(san)菱(ling)(ling)PLC內(nei)邏(luo)(luo)輯(ji)電(dian)(dian)(dian)(dian)(dian)路和(he)模擬(ni)電(dian)(dian)(dian)(dian)(dian)路的(de)(de)(de)(de)正(zheng)(zheng)常(chang)工(gong)作(zuo)。三(san)菱(ling)(ling)PLC工(gong)作(zuo)的(de)(de)(de)(de)邏(luo)(luo)輯(ji)電(dian)(dian)(dian)(dian)(dian)壓干(gan)擾(rao)容(rong)(rong)限較(jiao)低，邏(luo)(luo)輯(ji)地(di)(di)(di)(di)(di)電(dian)(dian)(dian)(dian)(dian)位(wei)的(de)(de)(de)(de)分布(bu)(bu)干(gan)擾(rao)容(rong)(rong)易(yi)影(ying)響(xiang)三(san)菱(ling)(ling)PLC的(de)(de)(de)(de)邏(luo)(luo)輯(ji)運算和(he)數(shu)據(ju) 存(cun)儲，造(zao)成數(shu)據(ju)混(hun)亂(luan)、程序跑飛或死機(ji)。模擬(ni)地(di)(di)(di)(di)(di)電(dian)(dian)(dian)(dian)(dian)位(wei)的(de)(de)(de)(de)分布(bu)(bu)將(jiang)導致測量精度下降，引起(qi)對(dui)(dui)信號測控的(de)(de)(de)(de)嚴重失真和(he)誤(wu)動作(zuo)。
6、來(lai)自(zi)三菱PLC系(xi)統內部的干擾
主要由(you)系統內(nei)部元器件及(ji)電路間的(de)相(xiang)(xiang)(xiang)互電磁輻射產生，如邏輯(ji)電路互輻射及(ji)其對模擬(ni)電路的(de)影(ying)響，模擬(ni)地與邏輯(ji)地的(de)相(xiang)(xiang)(xiang)互影(ying)響及(ji)元器件間的(de)相(xiang)(xiang)(xiang)互不匹配使(shi)用 等。這都屬于三菱(ling)PLC制造(zao)廠(chang)對系統內(nei)部進行(xing)電磁兼容設計的(de)內(nei)容，比較復雜，作為應用部門是無(wu)法(fa)改(gai)變，可不必過多(duo)(duo)考(kao)慮，但(dan)要選(xuan)擇具有較多(duo)(duo)應用實績或經過考(kao) 驗的(de)系統。
1、來自(zi)空間的輻射干擾
空間的(de)(de)輻(fu)(fu)射(she)(she)電(dian)磁場(chang)(chang)（EMI）主要是由電(dian)力網絡、電(dian)氣設(she)備(bei)的(de)(de)暫態過程、雷電(dian)、無線電(dian)廣播、電(dian)視、雷達(da)、高頻感應加熱設(she)備(bei)等(deng)產(chan)(chan)生的(de)(de)，通常稱為(wei)輻(fu)(fu)射(she)(she)干 擾(rao)(rao)，其分布極為(wei)復雜。若三(san)菱PLC系統置(zhi)于射(she)(she)頻場(chang)(chang)內(nei)，就回受(shou)到輻(fu)(fu)射(she)(she)干擾(rao)(rao)，其影響主要通過兩條路(lu)徑；一(yi)是直(zhi)接對三(san)菱PLC內(nei)部(bu)的(de)(de)輻(fu)(fu)射(she)(she)，由電(dian)路(lu)感應產(chan)(chan)生干擾(rao)(rao)； 二(er)是對三(san)菱三(san)菱PLC通信內(nei)網絡的(de)(de)輻(fu)(fu)射(she)(she)，由通信線路(lu)的(de)(de)感應引入干擾(rao)(rao)。輻(fu)(fu)射(she)(she)干擾(rao)(rao)與現(xian)場(chang)(chang)設(she)備(bei)布置(zhi)及設(she)備(bei)所產(chan)(chan)生的(de)(de)電(dian)磁場(chang)(chang)大小(xiao)，特別(bie)是頻率有關，一(yi)般(ban)通過設(she)置(zhi)屏蔽(bi) 電(dian)纜和(he)三(san)菱PLC局(ju)部(bu)屏蔽(bi)及高壓泄放元件進行保護
2、來自系統外引線(xian)的干擾
主(zhu)要通(tong)過(guo)電源和信(xin)號線引入，通(tong)常稱為(wei)傳(chuan)導干(gan)擾。這種干(gan)擾在我(wo)國(guo)工業現場較嚴(yan)重。
3、來自電(dian)源(yuan)的干擾(rao)
實踐證明，因電源引入的(de)干擾造成三菱(ling)PLC控制(zhi)系統故障的(de)情況很多，筆者在某工程調試中遇到過(guo)，后更換隔離(li)性(xing)能更高的(de)三菱(ling)PLC電源，問題才(cai)得到解(jie)決。
三菱(ling)三菱(ling)PLC系統的(de)正常供電(dian)(dian)(dian)電(dian)(dian)(dian)源(yuan)均由(you)電(dian)(dian)(dian)網供電(dian)(dian)(dian)。由(you)于電(dian)(dian)(dian)網覆蓋(gai)范圍廣，將(jiang)受到所有空(kong)間電(dian)(dian)(dian)磁干擾而在線(xian)路上感應(ying)電(dian)(dian)(dian)壓(ya)和電(dian)(dian)(dian)路。尤其是(shi)電(dian)(dian)(dian)網內部的(de)變化， 開關(guan)操作浪涌(yong)、大型(xing)電(dian)(dian)(dian)力設(she)備起停、交(jiao)直流轉動(dong)裝置引起的(de)諧波、電(dian)(dian)(dian)網短路暫態(tai)沖(chong)擊等，都通過輸電(dian)(dian)(dian)線(xian)路到電(dian)(dian)(dian)源(yuan)邊。三菱(ling)三菱(ling)PLC電(dian)(dian)(dian)源(yuan)通常采用隔(ge)離(li)電(dian)(dian)(dian)源(yuan)，但其機 構及制造(zao)工藝因素使其隔(ge)離(li)性并不(bu)理(li)想。實際上，由(you)于分布(bu)參數特別是(shi)分布(bu)電(dian)(dian)(dian)容的(de)存在，絕對(dui)隔(ge)離(li)是(shi)不(bu)可能的(de)。
4、來自信號線引入的干擾
與三(san)菱PLC控(kong)制(zhi)系(xi)(xi)統(tong)連接的(de)(de)各類信(xin)號(hao)(hao)傳(chuan)輸(shu)線，除了傳(chuan)輸(shu)有效(xiao)的(de)(de)各類信(xin)號(hao)(hao)之外(wai)，總會有外(wai)部干(gan)擾(rao)信(xin)號(hao)(hao)侵入。此干(gan)擾(rao)主要有兩種途徑：一(yi)是通(tong)過變(bian)送(song)器或共(gong)用 信(xin)號(hao)(hao)儀表的(de)(de)供(gong)電(dian)電(dian)源串入的(de)(de)電(dian)網干(gan)擾(rao)，這往往被忽略(lve)；二是信(xin)號(hao)(hao)線受空(kong)間電(dian)磁輻射感(gan)應的(de)(de)干(gan)擾(rao)，即信(xin)號(hao)(hao)線上(shang)的(de)(de)外(wai)部感(gan)應干(gan)擾(rao)，這是很嚴(yan)重(zhong)的(de)(de)。由信(xin)號(hao)(hao)引(yin)入干(gan)擾(rao)會引(yin)起(qi) I/O信(xin)號(hao)(hao)工作異常和(he)(he)測量精(jing)度大大降低(di)，嚴(yan)重(zhong)時將(jiang)引(yin)起(qi)元器件損(sun)傷。對于隔(ge)離性能差(cha)的(de)(de)系(xi)(xi)統(tong)，還將(jiang)導致信(xin)號(hao)(hao)間互相干(gan)擾(rao)，引(yin)起(qi)共(gong)地系(xi)(xi)統(tong)總線回流，造成邏輯數據變(bian) 化(hua)、誤動(dong)和(he)(he)死機(ji)。三(san)菱PLC控(kong)制(zhi)系(xi)(xi)統(tong)因(yin)信(xin)號(hao)(hao)引(yin)入干(gan)擾(rao)造成I/O模(mo)件損(sun)壞數相當嚴(yan)重(zhong)，由此引(yin)起(qi)系(xi)(xi)統(tong)故障的(de)(de)情況也很多。
5、來自接地(di)系統混亂時(shi)的干擾
接地(di)(di)(di)(di)(di)是提高電(dian)(dian)(dian)(dian)(dian)子設備電(dian)(dian)(dian)(dian)(dian)磁兼容(rong)(rong)性（EMC）的(de)(de)(de)(de)有效(xiao)手段(duan)之一(yi)。正(zheng)(zheng)確的(de)(de)(de)(de)接地(di)(di)(di)(di)(di)，既能抑制電(dian)(dian)(dian)(dian)(dian)磁干(gan)擾(rao)的(de)(de)(de)(de)影(ying)響(xiang)，又能抑制設備向外(wai)發出(chu)干(gan)擾(rao)；而(er)(er)錯誤(wu)的(de)(de)(de)(de)接地(di)(di)(di)(di)(di)，反而(er)(er)會(hui) 引入(ru)嚴重的(de)(de)(de)(de)干(gan)擾(rao)信號，使(shi)三(san)菱(ling)(ling)PLC系(xi)(xi)(xi)(xi)統(tong)將(jiang)無法正(zheng)(zheng)常(chang)工(gong)作(zuo)。三(san)菱(ling)(ling)PLC控制系(xi)(xi)(xi)(xi)統(tong)的(de)(de)(de)(de)地(di)(di)(di)(di)(di)線(xian)包括(kuo)系(xi)(xi)(xi)(xi)統(tong)地(di)(di)(di)(di)(di)、屏(ping)蔽(bi)(bi)地(di)(di)(di)(di)(di)、交流(liu)地(di)(di)(di)(di)(di)和(he)保護地(di)(di)(di)(di)(di)等(deng)。接地(di)(di)(di)(di)(di)系(xi)(xi)(xi)(xi)統(tong)混(hun)亂(luan)對(dui)(dui)三(san)菱(ling)(ling)PLC系(xi)(xi)(xi)(xi)統(tong)的(de)(de)(de)(de) 干(gan)擾(rao)主要是各個接地(di)(di)(di)(di)(di)點(dian)電(dian)(dian)(dian)(dian)(dian)位(wei)分布(bu)(bu)不(bu)均(jun)，不(bu)同接地(di)(di)(di)(di)(di)點(dian)間存(cun)在(zai)地(di)(di)(di)(di)(di)電(dian)(dian)(dian)(dian)(dian)位(wei)差(cha)，引起(qi)地(di)(di)(di)(di)(di)環(huan)路電(dian)(dian)(dian)(dian)(dian)流(liu)，影(ying)響(xiang)系(xi)(xi)(xi)(xi)統(tong)正(zheng)(zheng)常(chang)工(gong)作(zuo)。例如電(dian)(dian)(dian)(dian)(dian)纜(lan)屏(ping)蔽(bi)(bi)層(ceng)必須一(yi)點(dian)接地(di)(di)(di)(di)(di)，如果電(dian)(dian)(dian)(dian)(dian)纜(lan)屏(ping)蔽(bi)(bi)層(ceng)兩端A、 B都(dou)接地(di)(di)(di)(di)(di)，就存(cun)在(zai)地(di)(di)(di)(di)(di)電(dian)(dian)(dian)(dian)(dian)位(wei)差(cha)，有電(dian)(dian)(dian)(dian)(dian)流(liu)流(liu)過(guo)屏(ping)蔽(bi)(bi)層(ceng)，當發生異(yi)常(chang)狀態(tai)加雷(lei)擊時，地(di)(di)(di)(di)(di)線(xian)電(dian)(dian)(dian)(dian)(dian)流(liu)將(jiang)更(geng)大(da)(da)。 此外(wai)，屏(ping)蔽(bi)(bi)層(ceng)、接地(di)(di)(di)(di)(di)線(xian)和(he)大(da)(da)地(di)(di)(di)(di)(di)有可能構成閉(bi)合(he)環(huan)路，在(zai)變(bian)化磁場 的(de)(de)(de)(de)作(zuo)用下，屏(ping)蔽(bi)(bi)層(ceng)內(nei)有會(hui)出(chu)現感應電(dian)(dian)(dian)(dian)(dian)流(liu)，通(tong)過(guo)屏(ping)蔽(bi)(bi)層(ceng)與(yu)(yu)芯線(xian)之間的(de)(de)(de)(de)耦合(he)，干(gan)擾(rao)信號回(hui)路。若系(xi)(xi)(xi)(xi)統(tong)地(di)(di)(di)(di)(di)與(yu)(yu)其它接地(di)(di)(di)(di)(di)處理混(hun)亂(luan)，所產生的(de)(de)(de)(de)地(di)(di)(di)(di)(di)環(huan)流(liu)可能在(zai)地(di)(di)(di)(di)(di)線(xian)上(shang)產生不(bu)等(deng)電(dian)(dian)(dian)(dian)(dian)位(wei) 分布(bu)(bu)，影(ying)響(xiang)三(san)菱(ling)(ling)PLC內(nei)邏(luo)(luo)輯(ji)電(dian)(dian)(dian)(dian)(dian)路和(he)模擬(ni)電(dian)(dian)(dian)(dian)(dian)路的(de)(de)(de)(de)正(zheng)(zheng)常(chang)工(gong)作(zuo)。三(san)菱(ling)(ling)PLC工(gong)作(zuo)的(de)(de)(de)(de)邏(luo)(luo)輯(ji)電(dian)(dian)(dian)(dian)(dian)壓干(gan)擾(rao)容(rong)(rong)限較(jiao)低，邏(luo)(luo)輯(ji)地(di)(di)(di)(di)(di)電(dian)(dian)(dian)(dian)(dian)位(wei)的(de)(de)(de)(de)分布(bu)(bu)干(gan)擾(rao)容(rong)(rong)易(yi)影(ying)響(xiang)三(san)菱(ling)(ling)PLC的(de)(de)(de)(de)邏(luo)(luo)輯(ji)運算和(he)數(shu)據(ju) 存(cun)儲，造(zao)成數(shu)據(ju)混(hun)亂(luan)、程序跑飛或死機(ji)。模擬(ni)地(di)(di)(di)(di)(di)電(dian)(dian)(dian)(dian)(dian)位(wei)的(de)(de)(de)(de)分布(bu)(bu)將(jiang)導致測量精度下降，引起(qi)對(dui)(dui)信號測控的(de)(de)(de)(de)嚴重失真和(he)誤(wu)動作(zuo)。
6、來(lai)自(zi)三菱PLC系(xi)統內部的干擾
主要由(you)系統內(nei)部元器件及(ji)電路間的(de)相(xiang)(xiang)(xiang)互電磁輻射產生，如邏輯(ji)電路互輻射及(ji)其對模擬(ni)電路的(de)影(ying)響，模擬(ni)地與邏輯(ji)地的(de)相(xiang)(xiang)(xiang)互影(ying)響及(ji)元器件間的(de)相(xiang)(xiang)(xiang)互不匹配使(shi)用 等。這都屬于三菱(ling)PLC制造(zao)廠(chang)對系統內(nei)部進行(xing)電磁兼容設計的(de)內(nei)容，比較復雜，作為應用部門是無(wu)法(fa)改(gai)變，可不必過多(duo)(duo)考(kao)慮，但(dan)要選(xuan)擇具有較多(duo)(duo)應用實績或經過考(kao) 驗的(de)系統。
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