【正文】 nctions could be carried out since the diagnosis. The results can be automatically recorded. This increased transparency for its maintenance, facilitated. Rich functions for the PLC to provide a wide range of applications possible。s working methods for scanning plus interruption, which can guarantee it orderly, avoiding relay control systems often arise adventure petition, the results are always determined by its control。它采用一類可編程的存儲器，用于其內(nèi)部存儲程序，執(zhí)行邏輯運算 ,順序控制，定時，計數(shù)與算術(shù)操作等面向用戶的指令，并通過數(shù)字或模擬式輸入 /輸出控制各種類型的機械或生產(chǎn)過程。普遍計算機進行出入信息變換，多只考慮信息本身，信息的出入，只要人機界面好就可以了。 CPU 主要由運算 器、控制器、寄存器及實現(xiàn)它們之間聯(lián)系的數(shù)據(jù)、控制及狀態(tài)總線構(gòu)成， CPU 單元還包括外圍芯片、總線接口及有關(guān)電路。電源輸入類型有：交流電源 （ 220VAC 或 110VAC） ，直流電源（常用的為 24VAC）。 PLC 的 I/O 電路，都是專門設(shè)計的。 輸入電路時刻監(jiān)視著輸入狀況，并將其暫存于輸入暫存器中。這個區(qū)的每一對應位 （ bit） 稱之為輸入繼電器，或稱軟接點。這樣，用戶所要編的程序只是，內(nèi)存中輸入映射區(qū)到輸出映射區(qū)的變換，特別是怎么按輸入的時序變換成輸出的時序。當然，這個滯后不宜太大，否則，所實現(xiàn)的控制不那么及時，也就失去控制的意義。辦法是用 看門狗 （ Watching dog）。 公共處理工作有：循環(huán)時間監(jiān)控、外設(shè)服務及通訊處理等。又由于這個過程是永不停止地循環(huán)反復地進行著，所以，輸出總是反映輸入的變化的。這個映射也稱輸出刷新。把輸人暫存器的信息讀到 PLC 的內(nèi)存中，稱輸入刷新。 PLC 有多I/O 用點，一般 也就有多少個 I/O 用電路。什么樣的控制要求，就應有什么樣的用戶程序。 電源模塊 PLC 電源用于為 PLC 各模塊的集成電路提供工作電源。 CPU 的構(gòu)成 CPU 是 PLC 的核心，起神經(jīng)中樞的作用，每套 PLC 至少有一個 CPU，它按 PLC的系統(tǒng)程序賦予的功能接收并存貯用戶程序和數(shù)據(jù)，用掃描的方式采集由現(xiàn)場輸入裝置送來的狀態(tài)或數(shù)據(jù)，并存入規(guī)定的寄存器中，同時，診斷電源和 PLC 內(nèi)部電路的工作狀態(tài)和編程過程中的語法錯誤等。 PLC 的發(fā)明更經(jīng)濟的替代了舊自動化系統(tǒng) ,并利用成千上萬的繼電器和定時器 . 通常 ,一個 PLC 方案可以取 代成千上萬繼電器 . 通過初步規(guī)劃來控制汽車制造業(yè) ,而修改軟件所取代重新布線來操縱控制臺。 Can be used again and bring added value, etc., available to a greater return. Therefore, in most cases, its effectiveness is impressive 可編程控制器原理及其應用 可編程序控制器， PLC 或者說程序控制是用于小型計算機自動化現(xiàn)實控制的過程 ,如控制機器廠裝配線 ,通常采用的 PLC 微處理器 ,程序往往是控制復雜順序和工程師所寫的技術(shù) , 程序儲存在電池支持的記憶或 EEPROMS。 some PLC can be as high as 8090 degrees. Some PLC module may heat up a server, another server is functioning, but not in control, only for backup. Once work mainframe failure, the heat for an automatic replacement of its work. There are even redundant, a three to one design, CPU, I/O modules, power modules are redundant or some of the redundancy. Three sets at the same time, exports depend on the final decision of the majority of three results. This allows virtually zero probability of system failures, and ensures that everything goes well. Of course, such a system is a high cost, only for the particularly important occasions。 But by the information process, using soft logic links. Its work is based on the use of good information. Information is material and energy with its own laws. Facilitate the processing of information, facilitate munication and facilitate storage。 it can be a good human interface. And the PLC will also consider the reliability of information in and out, realtime, and the use of information and other issues. Special consideration must be given to how to adapt to the industrial environment, such as the ease of installation, interference and other issues. PLC Composition PLC is divided into two forms of fixed and modular (modular) in structure. Fixed PLC includes CPU boards, I/O boards, and panels shown, within blocks, electricity. All these elements into a portfolio as a whole are not detachable. Modular PLC includes CPU Modules, I/O module, memory, power supply module, or ill bed, these modules will be in accordance with the rules of portfolio allocation. CPU Composition CPU is the core of PLC, and it plays a central role. At least one PLC has one CPU, the PLC system procedures is to receive and store the user39。 At the same time, also for industrial automation systems, and control much of the intelligent move created conditions. Collection rich in functions such as PLC who is notcall controls。 But also to deal with contingency control of the PLC to ensure a timely response to emergency situations, so that PLC can reliably. Normal operating procedures for monitoring PLC, PLC systems are set up watchdog (Watching dog) monitoring procedures. Users begin operating procedures, first watchdog timer, and started the clock. When users operating procedures after a cycle, the timing check timer value. If overtime (generally not exceeding 100ms), reported to the police. Serious overtime, but also to stop the PLC. Users may take warning signals corresponding contingency measures. Timer value if the timing of overtime, then repeats the process startup, PLC will be normal. Clearly, with this watchdog to monitor the procedures to ensure the normal operation procedures PLC users can avoid the cycle of death and affect the reliability of its work. PLC many prevent and detect failures in the order to produce the modules work normal or not important reminder the preparation of the corresponding user procedures, and to PLC status of the work, and PLC control system monitoring to ensure its reliability. PLC on each call, also must operate the system includes procedures and substantially. This is the procedure of the system, and users may intervene. Failure of a corresponding error signal presentation It is in the PLC software and hardware aspects of a strong reliability measures in order to ensure that the features of the PLC have reliable. Its average time has up to tens of thousands of hours without failure. The average repair of a defect can be in a very short time, a few hours that a few minutes could. Why the use of PLC have been conducted survey. In response, most users of the PLC as a reliable work of the main reasons for its choice, namely to secure the, PLC as its preferred target . Economic The use of high technology will bring huge economic benefits and social benefits。 1 PLC 的發(fā)展歷程 在工業(yè)生產(chǎn)過程中，大量 的開關(guān)量順序控制，它按照邏輯條件進行順序動作，并按照邏輯關(guān)系進行連鎖保護動作的控制，及大量離散量的數(shù)據(jù)采集。而 PLC 則還要考慮信息出入的可靠性、實時性，以及信息的使用等問題。內(nèi)存主要用于存儲程序及數(shù)據(jù)，是 PLC 不可缺少的組成單元。 3 可編程控制器實現(xiàn)控制的要點 出入信息變換、可靠物理實現(xiàn)，可以說是 PLC 實現(xiàn)控制的兩個基本要點。輸入電路要對輸入信號進行濾波，以去掉高頻干擾。每一輸入點都有一個對應的存儲其信息的暫存器。這些位置成 1，表示接點通，置成 0 為接點斷。這是一個數(shù)據(jù)及邏輯處理 問題。 為此， PLC 的工作速度要快。只要循環(huán)超時，它可報警，或作相應處理。