詳細內容：TEKLOGIX 8255 TEKLOGIX 8255 五、PLC的接地 良好的接地是保證PLC可靠工作的重要條件，可以避免偶然發(fā)生的電壓沖擊危害。PLC的接地線與機器的接地端相接，接地線的截面積應不小于2mm2 ，接地電阻小于100Ω；如果要用擴展單元，其接地點應與基本單元的接地點接在一起。為了抑制加在電源及輸入端、輸出端的干擾，應給PLC接上專用地線，接地點應與動力設備（如電機）的接地點分開；若達不到這種要求，也必須做到與其它設備公共接地，禁止與其它設備串連接地。接地點應盡可能靠近PLC。 六、冗余系統(tǒng)與熱備用系統(tǒng) 在石油、化工、冶金等行業(yè)的某些系統(tǒng)中，要求控制裝置有極高的可靠性。如果控制系統(tǒng)發(fā)生故障，將會造成停產(chǎn)、原料大量浪費或設備損壞，給企業(yè)造成極大的經(jīng)濟損失。但是僅靠提高控制系統(tǒng)硬件的可靠性來滿足上述要求是遠遠不夠的，因為PLC本身可靠性的提高是有一定的限度。使用冗余系統(tǒng)或熱備用系統(tǒng)就能夠比較有效地解決上述問題。 1． 冗余控制系統(tǒng) 在冗余控制系統(tǒng)中，整個PLC控制系統(tǒng)（或系統(tǒng)中最重要的部分，如CPU模塊）由兩套完全相同的系統(tǒng)組成如圖2所示。兩塊CPU模塊使用相同的用戶程序并行工作，其中一塊是主CPU，另一塊是備用CPU；主CPU工作，而備用CPU的輸出是被禁止的，當主CPU發(fā)生故障時，備用CPU自動投入運行。這一切換過程是由冗余處理單元RPU控制的，切換時間在1~3個掃描周期，I/O系統(tǒng)的切換也是由RPU完成的。 2． 熱備用系統(tǒng) 在熱備用系統(tǒng)中，兩臺CPU用通訊接口連接在一起，均處于通電狀態(tài)如圖3所示。當系統(tǒng)出現(xiàn)故障時，由主CPU通知備用CPU，使備用CPU投入運行。這一切換過程一般不太快，但它的結構有比冗余系統(tǒng)簡單。 PLC系統(tǒng)的模擬量是一個變動很大的不穩(wěn)定的值，可能是如下原因： 你可能使用了一個自供電或隔離的傳感器電源，兩個電源沒有彼此連接，即模擬量輸入模塊的電源地和傳感器的信號地沒有連接。這將會產(chǎn)生一個很高的上下振動的共模電壓，影響模擬量輸入值。 另一個原因可能是模擬量輸入模塊接線太長或絕緣不好。 可以用如下方法解決： 1） 連接傳感器輸入的負端與模塊上的公共M 端以補償此種波動。（但要注意確保這是兩個電源系統(tǒng)之間的唯一聯(lián)系。） 背景是： 模擬量輸入模塊內部是不隔離的； 共模電壓不應大于 12V； 對于60Hz干擾信號的共模抑制比為40dB。 Cincinnati Circuit Board 3-531-2955A Rev. A 35312955A Cincinnati Circuit Board 3-531-2903A Rev. R 35312903A Cincinnati Circuit Board 3-531-2902A Rev. C 35312902A Cincinnati Circuit Board 3-531-2898A Rev. A 35312892A Cincinnati Circuit Board 3-531-2898A Rev. A 35312892A Cincinnati Circuit Board 3-531-2807A Rev. E 35312807A Cincinnati Circuit Board 3-531-2800A Rev A 35312800A Cincinnati Circuit Board 3-531-2741A Rev. A 35312741A Cincinnati Circuit Board 3-531-2617A Rev. D35312617A Cincinnati Circuit Board 3-531-2578A Rev A 35312578A Cincinnati Circuit Board 3-531-2445A Rev. A 35312445A Cincinnati Circuit Board 3-531-2412A Rev. 35312412A Cincinnati Circuit Board 3-531-2412A Rev. 35312412A Cincinnati Circuit Board 3-531-2355-D 3-531-2355 Cincinnati Circuit Board 3-531-2354-A Rev B 35312354A Cincinnati Circuit Board 3-531-2353A 35312353A Cincinnati Circuit Board 3-531-2352A Rev D35312352A Cincinnati Circuit Board 3-531-2351A Rev. C35312351A Cincinnati Circuit Board 3-531-2350A Rev. A 35312350A Cincinnati Circuit Board 3-531-2349-A Rev. A 35312349A Cincinnati Circuit Board 3-531-2343A Rev. D 35312343A Cincinnati Circuit Board 3-531-2237A Rev A 35312237A Cincinnati Circuit Board 3-531-2193A Rev. A 35312193A Cincinnati Circuit Board 3-531-2192A Rev B 35312192A Cincinnati Circuit Board 3-531-2191A Rev A 35312191A Cincinnati Circuit Board 3-531-2189A Rev. F 35312189A Cincinnati Circuit Board 3-531-2186A Rev. B 35312186A Cincinnati Circuit Board 3-531-2162A Rev. A 35312162A Cincinnati Circuit Board 3-531-2160A Rev. D 35312160A Cincinnati Circuit Board 3-531-2157A Rev. B 35312157A Cincinnati Circuit Board 3-531-2141A Rev. E 35312141A Cincinnati Circuit Board 3-531-2110A Rev. C 35312110A Cincinnati Circuit Board 3-531-2108A Rev. 35312108A Cincinnati Circuit Board 3-531-2108A Rev B 35312108A Cincinnati Circuit Board 3-531-2107A 35312107A Cincinnati Circuit Board 3-531-2095A Rev. B35312095A Cincinnati Circuit Board 3-531-2094A Rev B 35312094A Cincinnati Circuit Board 3-530-7289A Rev. E35307289A3-53O-7289A353O7289A Cincinnati Circuit Board 3 542 1133A Rev. C3-542-1133A35421133A Cincinnati Circuit Board 3 542 1133A Rev. C3-542-1133A35421133A Cincinnati Circuit Board 3 542 1048A3-542-1048A Rev. B35421048A3-542-1O48A Cincinnati Circuit Board 3 542 1009A m2 A 35421009 CINCINNATI Circuit Board 3 533 0768G 35330768G Rev. D CINCINNATI Circuit Board 3 533 0768G 35330768G Rev. C Cincinnati Circuit Board 3 533 0710 G PCB 35330710G CINCINNATI Circuit Board 3 533 0709G 0709 G35330709G Cincinnati Circuit Board 3 531 4609A3-531-4609A35314609A Rev B353146O9A Cincinnati Circuit Board 3 531 4319A3-531-4319A35314319A Rev A Cincinnati Circuit Board 3 531 4319A3-531-4319A35314319A Rev A Cincinnati Circuit Board 3 531 3953A3-531-3953A35313953A Rev - Cincinnati Circuit Board 3 531 3908A Rev B3-531-3908A35313908A3-531-39O8A Cincinnati Circuit Board 3 531 3674A3-531-3674A35313674A Rev B/E Cincinnati Circuit Board 3 531 3628A3-531-3628A35313628A Rev A/E Cincinnati Circuit Board 3 531 3525A3-531-3525A35313525A Rev A Cincinnati Circuit Board 3 531 3506A3-531-3506A35313506A Rev B/C/D353135O6A Cincinnati Circuit Board 3 531 3505A3-531-3505A35313505A Rev B/D353135O5A Cincinnati Circuit Board 3 531 3409A3-531-3409A35313409A Rev A353134O9A Cincinnati Circuit Board 3 531 3120A3-531-3120A35313120A Rev A3531312OA Cincinnati Circuit Board 3 531 3017A Rev. A35313017A3-531-3017A3 531 3O17A Cincinnati Circuit Board 3 531 3016A3-531-3016A35313016A Rev A35313O16A Cincinnati Circuit Board 3 531 2989A3-531-2989A35312989A Rev D Cincinnati Circuit Board 3 531 2893A Rev. A35312893A3-531-2893A Cincinnati Circuit Board 3 531 2893A Rev. A35312893A3-531-2893A Cincinnati Circuit Board 3 531 2860A Rev. E3-531-2860A 35312860A3 531 286OA Cincinnati Circuit Board 3 531 2827A Rev. A35312827A3-531-2827A Cincinnati Circuit Board 3 531 2805A Rev. A35312805A3-531-2805A3 531 28O5A Cincinnati Circuit Board 3 531 2804A Rev. B35312804A3-531-2804A3 531 28O4A Cincinnati Circuit Board 3 531 2804A Rev. B35312804A3-531-2804A3 531 28O4A Cincinnati Circuit Board 3 531 2785A Rev. C35312785A3-531-2785A Cincinnati Circuit Board 3 531 2585A Rev. C35312585A3-531-2585A Cincinnati Circuit Board 3 531 2409A Rev. A35312409A3-531-2409A3 531 24O9A Cincinnati Circuit Board 3 531 2365A Rev. A35312365A3-531-2365A Cincinnati Circuit Board 3 531 2356-A Rev. A35312356A3-531-2356A Cincinnati Circuit Board 3 531 2313A Rev. A35312313A3-531-2313A Cincinnati Circuit Board 3 531 2313A Rev. A35312313A3-531-2313A Cincinnati Circuit Board 3 531 2226-35312226-3-531-2226- Cincinnati Circuit Board 3 531 2226-35312226-3-531-2226- Cincinnati Circuit Board 3 531 2200A Rev. M35312200A3-531-2200A3 531 22OOA Cincinnati Circuit Board 3 531 2187A Rev. C35312187A3-531-2187A Cincinnati Circuit Board 3 531 2171A Rev H3-531-2171A35312171A Cincinnati Circuit Board 3 531 2159A Rev. B35312159A3-531-2159A Cincinnati Circuit Board 3 531 2156A Rev. E35312156A3-531-2156A Cincinnati Circuit Board 3 531 2147A Rev. B35312147A3-531-2147A Cincinnati Circuit Board 3 531 2144A Rev. B35312144A3-531-2144A Cincinnati Circuit Board 3 531 2140A Rev. B35312140A3-531-2140A3 531 214OA Cincinnati Circuit Board 3 531 2139A Rev. A35312139A3-531-2139A Cincinnati Circuit Board 3 531 2131A Rev. H35312131A3-531-2131A Cincinnati Circuit Board 3 531 2112A Rev. C35312112A3-531-2112A Cincinnati Circuit Board 3 531 2032A Rev. F35312032A3-531-2032ACIMTROL Board Cincinnati Circuit Board 3 531 2024A Rev. N35312024A3-531-2024A3 531 2O24A Cincinnati Circuit Board 3 531 2003A Rev B 35312003A3-531-2003A3 531 2OO3A Cincinnati Circuit Board 3 531 2002A Rev. B35312002A-3-531-2002A3 531 2OO2A Cincinnati Circuit Board 3 530 7387A Rev-G35307387A3-530-7387A3 53O 7387A Cincinnati Circuit Board 1269621CPCB-FSC-493-96PCBFSC49396Iss 4 Cincinnati Cinturn Series C Turning Centers Model MA Parts Manual 2-TC-8002-