【正文】
能模塊使用以及現(xiàn)場廣泛應(yīng)用的通訊功能的實現(xiàn)卻很少涉及。因此,利用現(xiàn)有實驗設(shè)備,并考慮到學(xué)生學(xué)習(xí)掌握的知識結(jié)構(gòu),設(shè)計開發(fā)了部分開放實驗項目。在 TD400C 的組態(tài)開放實驗中,通過配置顯示用戶菜單、報警菜單,與 S7200 CPU進行交互,對 CPU存儲區(qū)中的數(shù)據(jù)訪問和編輯,可實現(xiàn)小型的具有人機交互功能的控制系統(tǒng),如結(jié)合基礎(chǔ)實驗中運料小車自動 往返控制程序,可實現(xiàn)通過控制面板來控制小車運動狀態(tài),并在到達兩端限位位置時顯示報警畫面,同時在 TD400C 上修改小車在兩端停留的時間等,使實驗效果更加豐富生動,也讓學(xué)生了解掌握了生產(chǎn)現(xiàn)場采用的實際控制設(shè)備。 ( 3) 主模塊中帶的 PT100 溫度變送器將 0~100 攝氏度轉(zhuǎn)化成 0~10V作為模擬量輸入接入 CPU,將加熱器、風(fēng)扇等物理控制對象連接在 CPU 數(shù)字量輸出上,可實現(xiàn)有關(guān)模擬量的數(shù)據(jù)變換、手動 PID 控制編程、利用向?qū)瓿? PID 組態(tài)、 PID 參數(shù)自整定功能的實驗,使學(xué)生深刻理解并掌握工業(yè)現(xiàn)場模擬量 PID控制的相關(guān)知識和實現(xiàn)方法。 ( 5) S7200 CPU 的通信端口支持自由端口通信模式,可使用用戶自定義的通信協(xié)議實現(xiàn)與計算機或其他具有串行通信接口的設(shè)備進行通信。 基于 CP2431 以太網(wǎng)模塊設(shè)計的開放實驗 工業(yè)以太網(wǎng)是西門子 SIMATIC NET 開放通信系統(tǒng)的頂層,可以實現(xiàn)管理與控制網(wǎng)絡(luò)的一體化,甚至可以集成到互聯(lián)網(wǎng),為遠程控制和全球聯(lián)網(wǎng)提供了條件。在此,選擇現(xiàn)有的 CP2431 擴展模塊進行實驗,通過 Micro/WIN 中以太網(wǎng)向?qū)У暮唵谓M態(tài)即可完成對模塊的配置。另外,兩臺均配備 CP2431 模塊的 S7200 PLC,通過軟件編程并下載配置程序后,通過網(wǎng)線連接即可實現(xiàn)兩臺 S7200 PLC 基于以太網(wǎng)的數(shù)據(jù)交換。 基于觸摸屏設(shè)計的開放實驗 4 TD400C 只能顯示文本信息,而很多工業(yè)被控對象要求控制系統(tǒng)具有很強的人機界面功能,通過具有明確意義和提示信息的畫面來實現(xiàn)操作人員與控制系統(tǒng)之間的對話和相互作用。利用現(xiàn)有的觸摸屏設(shè)備設(shè)計開放實驗,可讓學(xué)生學(xué)習(xí)如何通過組態(tài)軟件 WinCC Flexible 對觸摸屏進行組態(tài)和傳送程序 [7],以及 HMI 和 PLC 的數(shù)據(jù)交換方式和數(shù)據(jù)結(jié)構(gòu),如讓學(xué)生在 HMI 上組態(tài)交通燈系統(tǒng)運行 監(jiān)控界面或電梯轎箱內(nèi)的操作界面,再結(jié)合基礎(chǔ)實驗中編寫的 S7200 十字路口交通燈控制程序或三層電梯控制程序,即可檢驗程序是否正確執(zhí)行,又可讓學(xué)生操作先進的設(shè)備,并學(xué)會其組態(tài)方法。 以上給出了利用模塊化 S7200 培訓(xùn)設(shè)備設(shè)計的部分開放實驗項目。 3 結(jié)束語 充分利用實驗室現(xiàn)有的模塊化 S7200 培訓(xùn)設(shè)備,研發(fā)大量的開放實驗項目,豐富了實驗內(nèi)容,開闊了學(xué)生視野,讓學(xué)生深刻感受到學(xué) PLC 有趣,學(xué) PLC 有用,同時又掌握了生產(chǎn)工業(yè)現(xiàn)場目前用的較多的西門子典型產(chǎn)品和最新技術(shù)的開發(fā)和應(yīng)用,全面認 識 PLC 控制技術(shù)、計算機工業(yè)組態(tài)監(jiān)控、觸摸屏控制、網(wǎng)絡(luò)等技術(shù)在實際自動化控制系統(tǒng)中的互相滲透和補充,學(xué)生的工程實踐能力、分析問題、解決問題的綜合能力都得到極大提高,更有信心去面對激烈的就業(yè)競爭,因此受到學(xué)生的普遍歡迎。 munication work together work technology is an advanced automatic control device. The current PLC has bee the three major branch of modern industrial automation Column (PLC, robotics, CAD / CAM), widely used in various fields of automation and control systems, various types of enterprises Industry require a certain amount of practical experience with such talent. Thus, PLC application technology has bee the industrial automation technology relevant professional technical personnel and university students to learn important lessons. Siemens SIMATIC S7200 series are small PLC, its high price in the domestic market large market share, because of its flexible and powerful munication features and other special advanced features are increasingly the more widely used in automatic control systems [1]. Siemens Automation and Drives Group is currently actively cooperate with colleges and universities Siemens to build the establishment of training center for smallscale automation, Qingdao University is one of them. Siemens to provide similar training center S7200 trainingrelated equipment and software development. Teachers take advantage of this favorable experimental conditions, based on the design of these devices to open .Made a number of pilot projects PLC open, so that school has spare capacity, enough to further strengthen the PLC application technology student learning, Understand and operate the most advanced automation equipment, the initial grasp of advanced control technologies of industrial automation and control system design technology patients, improve their practical ability to achieve training objectives applicable talents to meet munity needs for such technical personnel requirements. 1 Modular S7200 training equipment Principle and Application of PLC technology to learn and master the necessary hardware and software test platform to support. Siemens automatic in my school Group set up jointly with the driver of a small automated training centers, equipped with 10 sets of training equipment S7200, diagram at right .Figure (painted on