【正文】 ，以計(jì)算機(jī)為工具，以數(shù)值計(jì)算為手段，對(duì)存在的或設(shè)想中的系統(tǒng)進(jìn)行實(shí)驗(yàn)研究。本設(shè)計(jì)中，采用的是S7PLCSIM仿真軟件，它與編程軟件STEP7 ，同時(shí)具有以下優(yōu)點(diǎn)：① 在PG\PC上進(jìn)行，不依賴于硬件的S7程序測(cè)試；② 在程序開發(fā)早期消除錯(cuò)誤；③ 降低開發(fā)成本，加速開發(fā)進(jìn)程，提高開發(fā)質(zhì)量；④ 適用于LAD、FBD、S7GRAPH、S7HIGRAPH、CFC、S7PDIAG、WINCC等；⑤ 強(qiáng)大的‘STOP’操作功能；⑥ 真效果直觀，操作簡(jiǎn)單，自帶仿真操作全程錄像功能。否則，在顯示的對(duì)話框中改變模式；② 使用菜單命令視圖 斷點(diǎn)條來(lái)激活斷點(diǎn)工具欄；③ 將光標(biāo)放在希望設(shè)置斷點(diǎn)的語(yǔ)句行中；④ 使用菜單命令調(diào)試 設(shè)置斷點(diǎn)，或使用斷點(diǎn)工具欄中相應(yīng)的按鈕來(lái)設(shè)置斷點(diǎn)。寄存器的內(nèi)容顯示在可以放置到畫面任何處的窗口中；⑧ 要繼續(xù)運(yùn)行程序直到下一個(gè)斷點(diǎn)，選擇菜單命令調(diào)試 繼續(xù)調(diào)試 執(zhí)行下一個(gè)語(yǔ)句，在單步模式下進(jìn)行測(cè)試；⑨ 可以使用菜單命令調(diào)試 刪除斷點(diǎn)調(diào)試 刪除所有斷點(diǎn)。選擇菜單命令EXECUTEScan modeScan cont表示連續(xù)掃描方式。可以監(jiān)視STEP7軟件中梯形圖程序的運(yùn)行情況，選擇菜單命令Debugmonitor來(lái)監(jiān)視。③ 將程序?qū)懭氲絇LC中有兩種方式，一種是利用專用的編程器（手持式編輯器）將程序?qū)懭隤LC，另一種是在電腦上安裝編程軟件后，通過(guò)編程電纜寫入PLC。工程師首先在編程器上編寫程序，然后直接在現(xiàn)場(chǎng)寫入PLC中，如此一來(lái)，既節(jié)約了勞動(dòng)力的輸出，也減少了拆卸PLC過(guò)程中，器件的磨損。同時(shí)，編程軟件在互聯(lián)網(wǎng)絡(luò)已經(jīng)共享，不同的編程軟件使用于不同品牌的PLC，大大的降低了開發(fā)成本。所有的動(dòng)作由IB的各觸點(diǎn)觸發(fā)；QB模塊：此模塊為組態(tài)中的線圈的輸出點(diǎn)，隨著IB模塊觸點(diǎn)的動(dòng)作而做出相應(yīng)的響應(yīng)；T模塊：為組態(tài)中各定時(shí)器的實(shí)時(shí)變化顯示板。）第五章 結(jié)論設(shè)計(jì)程序是一個(gè)漫長(zhǎng)的過(guò)程，各種問(wèn)題和困難將會(huì)接連不斷的出現(xiàn)，需要我們靜下心來(lái)堅(jiān)持下去，不斷的探索問(wèn)題，尋找解決的方法。獨(dú)立設(shè)計(jì)完成一個(gè)PLC的控制系統(tǒng)，期間遇到了很多問(wèn)題，有的已經(jīng)解決，有的仍需進(jìn)一步完善，主要體現(xiàn)在幾個(gè)方面：① PLC的種類很多，各品牌的操作界面和編程方式差別很大，需要重新了解和學(xué)習(xí)相關(guān)的知識(shí)；[解決]② 編程過(guò)程中，一些細(xì)微的失誤可能導(dǎo)致整個(gè)系統(tǒng)功能不能實(shí)現(xiàn)，需要我們格外的細(xì)心，合理利用編譯軟件查錯(cuò)、解錯(cuò)，一步一步完善系統(tǒng)的操作功能；[解決]③ 調(diào)試過(guò)程中，每一款的仿真軟件必須和編程軟件相兼容，否則無(wú)法正常導(dǎo)出仿真結(jié)果；[解決]④ 功能方面，系統(tǒng)控制的站點(diǎn)不能完成地鐵的掉頭，例如：地鐵從南邊駛?cè)?，再?gòu)哪线咇傠x，單方向的進(jìn)離會(huì)導(dǎo)致系統(tǒng)控制的紊亂，使得信號(hào)燈和軌道變軌器不能正確的作出響應(yīng)；[未解決]⑤ 功能方面，系統(tǒng)有一次軌道變軌器多余的動(dòng)作，例如：地鐵從南邊駛?cè)?，從北邊駛離時(shí)，北邊軌道變軌器被觸發(fā)，多余的做一次變軌動(dòng)作，但對(duì)整個(gè)系統(tǒng)沒(méi)有影響。沒(méi)有杜老師的幫助也就沒(méi)有今天畢業(yè)設(shè)計(jì)的成果。參考文獻(xiàn)[1]范繼義，安全技術(shù)與管理[M].北京：中國(guó)鐵道出版社，2008．4[2]郭建新，鐵道信號(hào)基礎(chǔ)[M].北京：中國(guó)鐵道出版社，2007[3]周鈍熊，PLC在鐵路信號(hào)連鎖控制中心的應(yīng)用[M]．上海：上海鐵道學(xué)院，1999[4]趙志熙，車站信號(hào)控制系統(tǒng)[M]．北京：中國(guó)鐵道出版社，1993[5]趙躍華，可編程控制器及其應(yīng)用[M]．四川：電子科技大學(xué)出版社，1998[6]周治邦，鐵路信號(hào)現(xiàn)場(chǎng)總線控制的基本研究[M]．北京：鐵道學(xué)報(bào)，1999[7]中國(guó)機(jī)械自動(dòng)化研究委員會(huì)．PLC技術(shù)及應(yīng)用[M]．北京：機(jī)械工業(yè)出版社，2000[8]陳小鳳，鐵路信號(hào)現(xiàn)場(chǎng)控制技術(shù)[M]．北京：清華大學(xué)出版社，2000[9]常斗南，可編程控制器PLC工作原理[M]．北京：機(jī)械工業(yè)出版社，2001[10]朱善君，可編程器PLC仿真概述[M]．北京：清華大學(xué)出版社，1995[11]黃靜，PLC梯形圖編程技巧[M]．上海：上海鐵道學(xué)院出版社，1994[12]沈潔，PLC實(shí)際應(yīng)用概述[M]．北方交通大學(xué)出版社，1998[13]魏文君，計(jì)算機(jī)連鎖在鐵路運(yùn)輸中的應(yīng)用技術(shù)甘肅[N]．甘肅鐵道學(xué)報(bào)，1997[14]Online changes of train control system without train stopping [A].the academic journal of Cambridge of .[15]Railroad identity design and culture [A].New .[16]Railway Track and structures[C].[17]Development ofPLCVariable reluctance machines: Switched reluctance, stepper.Induction MachinesAmong all types or AC machines, the induction machine, particularly the cage type, is most monly used in industry. These machines are very economical, rugged, and reliable and are available in the ranges of fractional horse power (FHP) to multimegawatt capacity. Lowpower FHP machines are available in singlephase, but polyphase (threephase) machines are used, most often in variablespeed drives. Fig. 16A1 shows an idealized threephase, twopole induction motor where each phase windings in the stator and rotor is represented by a concentrated coil. The threephase windings are distributed sinusoidally and embedded is slots. In a cage machine, the rotor has a squirrel cagelike structure with shorted end rings. Basically, the machines can be looked upon as a threephase transformer with a rotating and shortcircuited secondary. Both stator and rotor cores are made with laminated ferromagnetic steel sheets. The air gap in the machine is practically uniform (nonsalient pole).One of the most fundamental principles of induction machines is the creation of a rotating and sinusoidally distributed magnetic field is the air gap. Neglecting the effect of slots and space harmonics due to nonideal winding distribution, it can be shown that a sinusoidal threephase balanced power supply in the threephase stator winding crates a synchronously rotating magnetic field. The rotational speed can be given as equation (16A1). Ne is called synchronous speed in rpm and Fe=ωe/2π is the stator frequency is Hz . P is the pole numbers of a machine.Ne=120Fe/PThe rotor winding will be subjected to a sweeping magnetic filed, and have inducing current in the shortcircuited rotor. The interaction of air gap flux and rotor mmf produces torque, make the rotor rotate. But the speed of the rotor is lees than synchronous speed. So it called induction machine or asynchronous machine. To meet the various staring and running requirements of a variety of industrial applications, several standard designs of squirrelcage motors are available from manufacturers stock. The torquespeed characteristics of the most mon designs, readily available and standardized in accordance with the criteria established by the National Electrical Manufacturers Association , are shown in Fig 16A2. The most significant design variable in these motors is the effective resistance of the rotor cage circuits.Class A Motors These machines are suitable for applications where the load torque is low at start(such as fan or pump loads)so that full speed is achieved rapidly, thereby eliminating the problem of overheating during starting. In large machines, lowvoltage starting is required to limit the starting current.Class B Motors Motors of this class are good generalpurpose motors and have a wide variety of industrial applications. They are particularly suitable for constantspeed drives, where the demand for starting torque is not severe. Examples are drives for fans, pumps, blowers, and motorgenerator sets.Class C Motors Class C motors are suitable for driving pressors, conveyors, and so forth.Class D Motors These motors are suitable for drives intermittent loads requiring rapid acceleration and highimpact loads such as punch presses or shears. In the case of impact loads, a flywheel is fitted to the system. As the motor speed falls appreciably with load impact, the flywheel delivers some of its kinetic energy during the impact.Synchronous MachinesA synchronous machine, as the name indicates, must rotate at synchronous speed, that is, the speed is uniquely related to the supply frequency, as indicated in Equation (16A1). It is a serious petitor to the induction machine invariablespeed drive applications. an idealized threephase, twopole wound field synchronous machine. The stator winding o