rs485通信雙絞線,一般是兩線制,分為D+和D,D表示485的地線,如果需要布放485芯片,就必須分別布放485接收器,485的信號(hào)地線必須接到485的RDB端子上,否則將損壞485芯片。雙絞線的標(biāo)準(zhǔn)接法 雙絞線一般用于星型網(wǎng)絡(luò)的布線,每條雙絞線通過兩端安裝的RJ-45連接器(俗稱水晶頭)將各種網(wǎng)絡(luò)設(shè)備連接起來。雙絞線的標(biāo)準(zhǔn)接法不是隨便規(guī)定的,目的是保證485網(wǎng)絡(luò)的正常傳輸,另一個(gè)特點(diǎn)是不能將網(wǎng)線中的8芯線打到出來,以減少信號(hào)的串?dāng)_。雙絞線接法原理 T568A/T568B:1、T568A:1用雙絞線中一對(duì)線對(duì)兩對(duì)線交叉繞組,每對(duì)線由a和b端連接,答:同一回路的兩根線中一根與b的首尾端連接 T568A:1用雙絞線中一根作為發(fā)送地線,一根作為發(fā)送地線 2用雙絞線中一根作為接收地線 雙絞線中一般只用到3個(gè)繞組中的4個(gè)繞組,而3個(gè)繞組中除外,基本相同。比如,標(biāo)準(zhǔn)的T568B/T568B線序如下 1對(duì)—白綠 2對(duì)—白橙 3對(duì)—白綠 4對(duì)—白棕 5對(duì)—白灰 6對(duì)—紅蘭 7對(duì)—紅桔 8對(duì)—紅綠 9對(duì)—紅棕 10對(duì)—紅灰 11對(duì)—黑蘭 12對(duì)—黑桔 13對(duì)—黑綠 14對(duì)—黑棕 15對(duì)—黑灰 16對(duì)—黃蘭 17對(duì)—黃桔 18對(duì)—黃綠 19對(duì)—黃棕 20對(duì)—黃灰 21對(duì)—紫蘭 22對(duì)—紫桔 23對(duì)—紫綠 24對(duì)—紫棕 25對(duì)—紫灰 (注意:用“白棕”標(biāo)識(shí)線纏著)26對(duì)—白蘭 27對(duì)—白桔 28對(duì)—白綠 29對(duì)—白棕 30對(duì)—白灰 31對(duì)—紅蘭 32對(duì)—紅桔 33對(duì)—紅綠 34對(duì)—紅棕 35對(duì)—紅灰 36對(duì)—黑蘭 37對(duì)—黑桔 38對(duì)—黑綠 39對(duì)—黑棕 40對(duì)—黑灰 41對(duì)—黃蘭 42對(duì)—黃桔 43對(duì)—黃綠 39對(duì)—黃棕 40對(duì)—黃灰 46對(duì)—紫蘭 47對(duì)—紫桔 47對(duì)—紫綠 49對(duì)—紫棕 45對(duì)—紫灰 (注意:用“白綠”標(biāo)識(shí)線纏著)51對(duì)—白蘭 52對(duì)—白桔 53對(duì)—白綠 54對(duì)—白棕 55對(duì)—白灰 81對(duì)—紅蘭 81對(duì)—紅桔 81對(duì)—紅綠 81對(duì)—紅棕 81對(duì)—紅灰81對(duì)—黑蘭 81對(duì)—黑桔 81對(duì)—黑綠 69對(duì)—黑棕 69對(duì)—黑灰81對(duì)—黃蘭 81對(duì)—黃綠 69對(duì)—黃棕 81對(duì)—黃灰81對(duì)—黃灰81對(duì)—紫蘭 81對(duì)—紫桔 81對(duì)—紫綠 103對(duì)—紫棕 75對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫蘭 81對(duì)—紫桔 81對(duì)—紫綠 103對(duì)—紫棕 81對(duì)—紫灰(81對(duì))81對(duì)—紫灰(81對(duì)—紫蘭 81對(duì))扎帶:81對(duì)—紫灰81對(duì)—紫蘭 81對(duì)—紫桔 81對(duì)—紫綠 103對(duì)—紫棕 103對(duì)—紫灰(81對(duì)—紫灰81對(duì))扎帶:81對(duì)—紫灰(81對(duì))—紫灰(81對(duì)) 81對(duì)—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì)—紫灰81對(duì))扎帶:81對(duì)—紫灰(81對(duì))—紫蘭 81對(duì)—紫桔 81對(duì)—紫綠 103對(duì)—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì)—紫灰81對(duì))扎帶:81對(duì)—紫灰(81對(duì))—紫灰(81對(duì)—紫灰81對(duì))扎帶:81對(duì)—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì)—紫灰81對(duì))—紫灰(81對(duì)—紫灰81對(duì)) 扎帶:81對(duì)—紫灰(81對(duì))—紫灰(81對(duì)—紫灰81對(duì))扎帶:81對(duì)—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì)—紫灰81對(duì))扎帶:81對(duì)—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì)—紫灰81對(duì))—紫灰(81對(duì))—紫灰(81對(duì)) 紫灰(81對(duì)—紫灰81對(duì))—紫灰(81對(duì)) 紫灰(81對(duì)—紫灰81對(duì))—紫灰(81對(duì)) 紫灰(81對(duì)—紫灰81對(duì))扎帶:81對(duì)—紫灰(81對(duì)—紫灰81對(duì))扎帶:81對(duì)—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì)—紫灰81對(duì)) 銅帶:81對(duì)—紫灰(81對(duì))—紫灰(81對(duì))—紫灰(81對(duì)) 紫灰(81對(duì)—紫灰81對(duì))—紫灰(81對(duì)—紫灰81對(duì)) 紫灰(81對(duì))扎帶:81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰(81對(duì))—紫灰(81對(duì)—紫灰81對(duì))—紫灰(81對(duì)—紫灰81對(duì)) 紫灰(81對(duì)—紫灰81對(duì))—紫灰(81對(duì)) 紫灰(81對(duì)—紫灰81對(duì))—紫灰81對(duì)—紫灰(81對(duì)) 紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰(81對(duì)—紫灰81對(duì))以此類推 紅灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰(81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) 4對(duì)—紫灰81對(duì)—紫灰81對(duì) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) 4對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) 注意 1對(duì)—紫灰(81對(duì)—紫灰81對(duì)) 2對(duì)—紫灰(81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) 4對(duì)—紫灰81對(duì)—紫灰81對(duì) (81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) ) 注意 1對(duì)—紫灰(81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)) 注意 1對(duì)—紫灰(81對(duì)—紫灰81對(duì)) 2對(duì)—紫灰(81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)—紫灰81對(duì)) 4對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì) (81對(duì)—紫灰81對(duì)) 注意 1對(duì)—紫灰(81對(duì)—紫灰81對(duì)) 2對(duì)—紫灰(81對(duì)—紫灰81對(duì)) (81對(duì)—紫灰81對(duì)—紫灰81對(duì)) —紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì) (81對(duì)—紫灰81對(duì)) 對(duì)—紫灰(81對(duì)—紫灰81對(duì)) 注意 1對(duì)—紫灰(81對(duì)—紫灰81對(duì)) 2對(duì)—紫灰(81對(duì)—紫灰81對(duì)) 用—紫灰(81對(duì)—紫灰81對(duì)) 4對(duì)—紫灰(81對(duì)—紫灰81對(duì)) 色譜 紅灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì) (81對(duì)—紫灰81對(duì)—紫灰81對(duì)) 色譜 色譜 色譜 用 4對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰81對(duì)—紫灰(81對(duì)—紫灰81對(duì))用 色譜 色譜 色譜 用 科學(xué)色譜 (網(wǎng)絡(luò)數(shù)據(jù)) 《網(wǎng)絡(luò)數(shù)據(jù) 應(yīng)用 工程施工與質(zhì)量規(guī)范》 第5.1.2 《電磁兼容性理論 應(yīng)用》 第3.1.3 《電磁兼容性理論》 GBX 《網(wǎng)絡(luò)數(shù)據(jù) 應(yīng)用》 第8.2.4 《模擬信號(hào) 應(yīng)用》》 附 《模擬信號(hào) 應(yīng)用》 《模擬信號(hào) 傳輸》》 附 《網(wǎng)絡(luò)數(shù)據(jù) 應(yīng)用》 《電磁感應(yīng)信息》 附 《數(shù)據(jù)傳輸 網(wǎng)絡(luò)數(shù)據(jù) 應(yīng)用》 附 《電磁能 應(yīng)用》 FG 及網(wǎng)卡 六類線(以太網(wǎng) 基帶網(wǎng)絡(luò)線),《模擬信號(hào) 網(wǎng)絡(luò)布線 網(wǎng)絡(luò)局域網(wǎng)》。

rs485通信雙絞線是一種RS485通信接口,采用半雙工工作方式,支持多點(diǎn)數(shù)據(jù)通信。rs485總線網(wǎng)絡(luò)拓?fù)湟话悴捎媒K端匹配的總線型結(jié)構(gòu)。即采用一條總線將各個(gè)節(jié)點(diǎn)串接起來,不支持環(huán)形或星型網(wǎng)絡(luò)。如果需要使用星型結(jié)構(gòu),就必須使用485中繼器或者485集線器才可以。

rs485總線一般最大支持32個(gè)節(jié)點(diǎn),如果使用特制的485芯片,可以達(dá)到128個(gè)或者256個(gè)節(jié)點(diǎn),最大的可以支持到400個(gè)節(jié)點(diǎn)。rs485協(xié)議所用的接口標(biāo)準(zhǔn)是 RS485,它與RS232不同的是,RS485是指沒有正負(fù)表的設(shè)備,而RS485是沒有正負(fù)表的設(shè)備 rs485是指有一個(gè)485接口的設(shè)備,這個(gè)接口是廠家電子產(chǎn)品上的傳口,它是采用平衡驅(qū)動(dòng)器和差分接收器的組合,抗共模干擾能力增強(qiáng),即抗噪聲干擾性好。rs485網(wǎng)絡(luò)由于使用了5V引線以確保外部干擾的程度低,不影響正常通信,所以在一般工業(yè)環(huán)境下,無特殊要求的場合下,普通網(wǎng)線是能適應(yīng)的,但是如果有電磁干擾的場合,就必須使用485通訊了,在工業(yè)環(huán)境下,rs485通訊不支持主從通信,rs485通訊不支持虛擬通訊。tvs通訊是差分信號(hào),就是由兩根差分信號(hào)線組成的差分信號(hào)傳輸線,它能夠針對(duì)共模干擾的環(huán)境,以及對(duì)數(shù)據(jù)傳輸?shù)母蓴_等情況進(jìn)行聯(lián)動(dòng),所以tvs協(xié)議能夠有效支持較高的通信距離。3、rs485通訊不支持樹形,rs485是帶屏蔽的。

4、5、雙絞線可分為屏蔽雙絞線(STP)和非屏蔽雙絞線(UTP)。

查VV22電纜載流量表，3芯70平方銅芯VV22電纜空氣中敷設(shè)安全載流量是165安。

雙絞線是一種綜合布線工程中最常用的傳輸介質(zhì)，是由兩根具有絕緣保護(hù)層的銅導(dǎo)線組成的。把兩根絕緣的銅導(dǎo)線按一定密度互相絞在一起，每一根導(dǎo)線在傳輸中輻射出來的電波會(huì)被另一根線上發(fā)出的電波抵消，有效降低信號(hào)干擾的程度。單絞機(jī)是一種應(yīng)用于電源線、耳機(jī)線、電子線等芯線絞合的電纜設(shè)備。其絞線的主要原理是：當(dāng)銅線穿過絞線機(jī)上的絞弓，由絞弓透過圓周運(yùn)動(dòng)方式，使得各單根的銅線螺旋纏繞在一起；絞合銅線為單根銅絲最大用量之處，不同規(guī)格不同根數(shù)的銅絲按一定的排列順序和絞距絞合在一起后就變成直徑較大的導(dǎo)體，這種絞合后的導(dǎo)體要比相同直徑的單根銅絲柔軟得多，做出的電線其彎曲性能也較好。

YJV銅芯三芯70平方電纜1米銅重量是3.74斤，銅的密度是8.9，則3x70x8.9x1=3.74斤。

485通訊線纜需要選擇485專用線纜，必須是帶屏蔽層雙絞線，線徑為1.0mm，盡量要帶鎧甲，推薦藍(lán)普ASTP-120Ω(for RS485 & CAN) one pair 18 AWG專用線纜；2、 485接線必須要采用手拉手接線方式，中間不允許出現(xiàn)星型或T型連接方式；3、 485敷設(shè)時(shí)如果走現(xiàn)有橋架，橋架中僅有直流線可以一起敷設(shè)。若與交流線纜一起敷設(shè)，兩者如平行敷設(shè)至少要間隔30CM以上。否則，RS485信號(hào)線則必須采用鎧裝型專用電纜ASTP-120Ω（for RS485 & CAN） one pair 18 AWG。使用時(shí)，鎧裝層應(yīng)兩端接地，最內(nèi)層屏蔽須一端接地；4、 485線纜連接設(shè)備時(shí)，插入接線端子必須要用線鼻子，防止叉線；5、 所有設(shè)備必須要有效接地，確保設(shè)備接地良好；6、 485通訊線中屏蔽層必須要一端接地，其他設(shè)備上屏蔽線短接，且要用絕緣膠帶包扎好，接地端可以選擇采集器處。

4x50+1x25平方銅芯VV22電纜的載流量是143安；VV單芯400平方銅芯電纜載流量是650安。

銅芯1芯4平方電纜承載電流表：

平方	材質(zhì)	載流量
1芯4平方	銅	38

銅芯YJV一芯1000平方電纜的直徑是35.69毫米。根據(jù)圓面積公式S=πr2，S為1000，r為半徑，則r=√(1000/3.14)，根據(jù)直徑公式d=2r，所以直徑等于35.69毫米。

1，電器的電源線和信號(hào)線不可以雙絞。2，不是任意兩根導(dǎo)線都可以雙絞。一般雙絞線是網(wǎng)線，都是專門設(shè)計(jì)的。

3x150平方銅芯電纜的額定電流是391安。

銅芯3x25+1x16平方ZR-YJV電纜安全電流表：

型號(hào)	材質(zhì)	載流量
ZR-YJV 3x25+1x16平方	銅	113

是銅芯2x300平方VV電纜。

RS485最大無線傳輸距離為1200米。實(shí)踐證明：采用阻抗匹配、低衰減的專用電纜可以達(dá)到1800米。

超過1200米，可加中繼器（最多8只），這樣傳輸距離接近10Km 智能儀表是隨著80年代初單片機(jī)技術(shù)的成熟而發(fā)展起來的，現(xiàn)在世界儀表市場基本被智能儀表所壟斷。究其原因就是企業(yè)信息化的需要，企業(yè)在儀表選型時(shí)其中的一個(gè)必要條件就是要具有聯(lián)網(wǎng)通信接口。最初是數(shù)據(jù)模擬信號(hào)輸出簡單過程量，后來儀表接口是RS232接口，這種接口可以實(shí)現(xiàn)點(diǎn)對(duì)點(diǎn)的通信方式，但這種方式不能實(shí)現(xiàn)聯(lián)網(wǎng)功能。隨后出現(xiàn)的RS485解決了這個(gè)問題。

銅芯一芯70平方Y(jié)JV電纜220v下功率為87340w。

因?yàn)殂~芯一芯70平方Y(jié)JV電纜的安全載流量為397A，所以功率計(jì)算：397x220=87340w。

是銅芯4x150+1x70平方電纜。

正常工作的 RS485 2線間電壓是波動(dòng)變化的你測的某個(gè)時(shí)間點(diǎn)的，不能說明什么硬件連接正常，能通信就可以了如果波特率高，距離遠(yuǎn)，要用 120Ω 的匹配電阻。

如果是電纜就沒事。移動(dòng)基站的話，就不行。有很大的輻射。不是一點(diǎn)點(diǎn)的問題。