【正文】 LC 采用半導(dǎo)體集成電路作定時器，時鐘脈沖由晶體振蕩器產(chǎn)生，精度高，定時范圍寬，用戶可根據(jù)需要在程序中設(shè)定定時值，修改方便，不受環(huán)境的影響，且 PLC 具有計數(shù)功能，而電器控制系統(tǒng)一般不具備計數(shù)功能。 （ 5） 從可靠性和可維護性上看，由于電 氣 控制系統(tǒng)使用了大量的機械觸點，其存在機械磨損、電弧 燒傷等，壽命短，系統(tǒng)的連線多，所以可靠性和可維護性 33 較差。而 PLC 大量的開關(guān)動作由無觸點的半導(dǎo)體電路來完成，其壽命長、可靠性高， PLC 還具有自診斷功能，能查出自身的故障，隨時顯示給操作人員，并能動態(tài)地監(jiān)視控制程序的執(zhí)行情況，為現(xiàn)場調(diào)試和維護提供了方便 。 34 5 結(jié)論 通過 Z3040 搖臂鉆床的電氣控制原理圖 可以看出傳統(tǒng) 繼電器 接觸器控制系統(tǒng)，觸點多、 接 線復(fù)雜 、 維修困難等缺點。 而 PLC 控制系統(tǒng) 與傳統(tǒng) 繼電器 接觸器系統(tǒng)相比，具有 通用性強、 結(jié)構(gòu)簡單、體積小、易于安裝、性能優(yōu)越、 可靠性高、 編 程簡單、抗干擾能力強、 使用維護方便 、應(yīng)用靈活等優(yōu)點。因此，本設(shè)計把 Z3040 搖臂鉆床的電氣控制改造成 PLC 控制，提高 了 搖臂鉆床的性能。 本設(shè)計先對 PLC 的產(chǎn)生和發(fā)展、用途及特點、基本結(jié)構(gòu)和工作原理等進行介紹， 然后 再 根據(jù) Z3040 搖臂鉆床的機床結(jié)構(gòu)、運動形式及工作原理進行了分析 ，制定了 PLC 改造的設(shè)計方案并敘述了設(shè)計流程 ， 其中包括 PLC 類型的選擇 、 I/O地址的分配、 接線圖 和 梯形圖 的 繪制 等 ，還對 Z3040 搖臂鉆床電控系統(tǒng)改造后PLC 系統(tǒng) 的一些程序 進行 仿真調(diào)試 。 Z3040 搖臂鉆床 電控系統(tǒng) 的改造，使設(shè)備的工作效率 和可靠性 ，以及其 自動化程度都有很大提高。 35 參考文獻 [1]胡文金 . 可編程序控制器實訓(xùn)教程 . 重慶：重慶大學(xué)出版社， 2021 [2]王淑英 . 電氣控制與 PLC應(yīng)用 . 北京：機械工業(yè)出版社， 2021 [3]孫德勝，李偉 . PLC操作實訓(xùn) . 北京：機械工業(yè)出版社， 2021 [4]陳定明 . 電機與控制 . 北京：高等教育出版社， 2021 [5]李樹海 . 低壓運行維修電工基本技能圖解 . 北京：中國電力出版社， 2021 [6]姜治臻 . PLC項目實訓(xùn) . 北京：高等教育出版社， 2021 [7]阮友德 . 電氣控制與 PLC實訓(xùn)教程 . 北京：人民郵電出版社， 2021 [8]高 勤 . 電氣及 PLC控制技術(shù) . 北京：高等教育出版社， 2021 [9]鄭鳳翼，楊洪升 . 怎樣看電氣控制電路圖 . 北京：人民郵電出版社， 2021 [10]劉玉娟 . PLC編程技能訓(xùn)練 . 北京：高等教育出版社， 2021 [11]王傳艷 . 工作過程系統(tǒng)化核心教程 PLC應(yīng)用 . 北京：高等教育出版社， 2021 [12]張中洲 . PLC技術(shù)與技能訓(xùn)練 . 北京：高等教育出版社， 2021 [13]廖常初 . PLC編程及應(yīng)用 . 北京：機械工業(yè)出版社， 2021 36 致謝 本 設(shè)計 是在黃河老師的悉心指導(dǎo)下完成的， 黃河 老師 淵博的知識、豐富的實踐經(jīng)驗 和認(rèn)真負(fù)責(zé)的工作態(tài)度 、 嚴(yán)謹(jǐn)?shù)闹螌W(xué) 的 精神 令我終生難忘 。 特別要感謝黃河老師 借了很多本 關(guān)于 三菱 PLC 知識方面的書給我，這些書讓我受益匪淺。 再次向他表示衷心的感謝。 對關(guān)心和指導(dǎo)過我的各位老師及幫助過我的同學(xué) 們 表示衷心的感謝 ， 同時還要感謝在百忙之中來參加我們畢業(yè)答辯的評審老師們 ，對本設(shè)計的不足之處敬請 各位評審老師 批評指正 。 37 附錄 A 基于三菱 PLC的 Z3040搖臂鉆床電控系統(tǒng) 原理圖 38 附錄 B Z3040搖臂鉆床 PLC電 控系統(tǒng)語句表程序 g an employment tribunal clai Employment tribunals sort out disagreements between employers and employees. You may need to make a claim to an employment tribunal if: ? you don39。t agree with the disciplinary action your employer has taken against you ? your employer dismisses you and you think that you have been dismissed unfairly. For more information about dismissal and unfair dismissal, see Dismissal. You can make a claim to an employment tribunal, even if you haven39。t appealed against the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any pensation awarded to you as a result of your failure to appeal. Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are plaining about happened. If your application is received after this time limit, the tribunal will not usually accept i. If you are worried about how the time limits apply to you, take advice from one of the anisations listed under Further help. 38 Employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation. Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the anisations listed under Further help. If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your pensation if you win the case. This is known as a damagesbased agreement. In England and Wales, your solicitor can39。t charge you more than 35% of your pensation if you win the case. If you are thinking about signing up for a damagesbased agreement, you should make sure you39。re clear about the terms of the agreement. It might be best to get advice from an experienced adviser, for example, at a Citizens Advice Bureau. To find your nearest CAB, including those that give advice by , click on nearest CAB. For more information about making a claim to an employment tribunal, see Employment tribunals. The (lack of) air up there Watch mCayman Islandsbased Webb, the head of Fifa39。s antiracism taskforce, is in London for the Football Association39。s 150th anniversary celebrations and will attend City39。s Premier League match at Chelsea on Sunday. I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC Sport. For me it39。s about how he felt and I would like to speak to him first to find out what his experience was. Uefa has opened disciplinary proceedings against CSKA for the racist behaviour of their fans during City39。s 21 win. Michel Platini, president of European football39。s governing body, has also ordered an immediate investigation into the referee39。s actions. CSKA said they were surprised and disappointed by Toure39。s plaint. In a statement the Russian side added: We found no racist insults from fans of CSKA. Age has reached the end of the beginning of a word. May be guilty in his seems to passing a lot of different life became the appearance of the same day。 May be back in the past, to oneself the paranoid weird belief disillusionment, these days, my mind has been very messy, in my mind constantly. Always feel oneself should go to do something, or write something. Twenty years of life trajectory deeply shallow, suddenly feel something, do it. 一字開頭的年齡已經(jīng)到了尾聲。或許是愧疚于自己似乎把轉(zhuǎn)瞬即逝的很多個不同的日子過成了同一天的樣子；或許是追溯過去，對自己那些近乎偏執(zhí)的怪異信念的醒悟，這些天以 38 來，思緒一直很凌亂，在腦海中不斷糾纏。總覺得自己自己似乎應(yīng)該去做點什么，或者寫點什么。二十年的人生軌跡深深淺淺，突然就感覺到有些事情，非做不可了。 The end of our life, and can meet many things really do? 而窮盡我們的一生，又能遇到多少事情是真正地非做不可？ During my childhood, think lucky money and new clothes are necessary for New Year, but as the advance of the age, will be more and more found that those things are optional。 Junior high school, thought to have a crush on just means t