| 詳細(xì)參數(shù) | |||
|---|---|---|---|
| 品牌 | foxboro | 型號 | FBC01 |
| 結(jié)構(gòu)形式 | 模塊式 | 安裝方式 | 控制室安裝 |
| LD指令處理器 | 硬PLC | 加工定制 | 否 |
FBC01
曾經(jīng)有一個愛滑雪的工程師，名叫迪克·莫利，他從MIT畢業(yè)之后進(jìn)入一家公司，從事飛行器、與通訊系統(tǒng)的設(shè)計工作。平靜的迪克認(rèn)真地做著設(shè)計、沉浸其中，雖沒人注意，但正是他，永久的改變了整個制造業(yè)。
1968年1月1日酩酊大醉之后，迪克靈光乍現(xiàn)寫下了人類歷史上第一個PLC的藍(lán)圖。這個還沒命名的東西應(yīng)有如下特性：沒有過程中斷；直接映像進(jìn)入存儲器；沒有軟件處理重復(fù)的事務(wù)；堅固的設(shè)計以便能真正地工作；運(yùn)行速度慢，當(dāng)然，莫利先生隨后認(rèn)識到該特性是一個錯誤；還要有自己的編程語言，值得一提的是，幾個月之后，梯形圖邏輯就此問世。
后來，迪克就和他的朋友創(chuàng)立了莫迪康公司來完成這個構(gòu)想。PLC隨后誕生了
第三次工業(yè)革命的興起，給了莫利先生的PLC團(tuán)隊一個青史留名的機(jī)會。
通用汽車公司發(fā)現(xiàn)，每次生產(chǎn)新的車型，整個生產(chǎn)線就要重新折騰一遍，成千上萬根電纜都要重新接，不但時間長，還容易出錯，出了錯還不好找，號稱“查找5小時，修理5分鐘”。1968年，為了適應(yīng)汽車型號不斷更新的需求，并能在競爭激烈的汽車工業(yè)中占有優(yōu)勢，通用汽車公司提出要研制一種新型的工業(yè)控制裝置來取代繼電器控制裝置，為此，擬定了10項公開招標(biāo)的技術(shù)要求。包括Modicon084在內(nèi)的3款產(chǎn)品參與競爭，另外兩個品牌分別是，美國數(shù)字設(shè)備公司的PDP-14和3-I公司的PDQ-II。
通過競爭，Modicon084憑借操編程簡單、操作便利、環(huán)境適應(yīng)性強(qiáng)等特點(diǎn)成功獲得了通用汽車的控制器研發(fā)項目，最后通用從莫迪康采購了100萬美元左右的設(shè)備，從此PLC開始風(fēng)行世界。
Also the DoS attacks against the 4-way handshake indicated in [15] are also worth considering. Another possible attack in PLC comes from the manipulation of the impedance of the electrical line or the line itself. This may cause lead to message deletion or, worse, message interception. The implementation of such an attack seems difficult and requires specific topologies that do not seem to be common. In any case the attack would be a Man in the Middle attackfrom which the specification is already protected because it provides for mutual authentication. Another aspect being improved is the computation burden created by the need to change the key at every hop. One mechanism to improve this aspect is to use a single key to manage the HE and the Repeaters. Another is to define a protocol to agree a single key for transmission between pairs of CPE. VII. CONCLUSIONS
The earlier OPERA Phase1 PLC specification has been detected to be vulnerable to many known security attacks.This led to the definition of a new OPERA PLC specification able to overcome the known attacks. This new OPERA specification was bted to the IEEE as the proposal of the OPERA consortium for the IEEE standard on PLC access systems. The proposal is based on the principles of standard IEEE802.11i. This is good for many reasons. One is compatibility with wireless in hybrid systems and devices. Another is to use known and proved standards. Nevertheless there are several differences to adapt the specification to the nature of PLC. The main ones are the following:
-Instead of applying Encryption and MIC computation to the same block of data, Encryption is applied to Bursts while the MIC is appended to OPERA packets. This makes the system stronger against the very noisy PLC channels.
