【導讀】1．可編程序控制器通過____________、____________的輸入和輸出，控制各類型的機械或生產(chǎn)過程。2．熔斷器主要防止電路的____________或____________。3．電磁式接觸器主要由____________、____________和滅弧裝置和其它部分組成。5．.熱繼電器是利用電流流過發(fā)熱元件產(chǎn)生熱量來使檢測元件____________，進而推動機構(gòu)動作的一種保。護電器，主要被用作電動機的長期保護。2．PLC是專門用來完成邏輯運算的控制器。3．PLC具有監(jiān)控和自診斷能力，若發(fā)生故障或異常，可及時判斷故障原因，并排除故障。4．由于PLC的可靠性和抗干擾能力較差，所以不能在惡劣的工業(yè)環(huán)境中應(yīng)用。5．在工業(yè)自動化領(lǐng)域，PLC，DCS與IPC技術(shù)正在趨于融合。6．開啟式負荷開關(guān)可用于手動頻繁的接通和斷開帶負荷的電路，以及作為線路末端的短路保護。7．為防止無關(guān)人員誤操作，在重要場合應(yīng)選用帶鑰匙操作的按鈕。10．低壓斷路器即低壓自動空氣開關(guān)，簡稱自動開關(guān)，可實現(xiàn)電路的短路、過載、失電壓與欠電壓的保護，20．電氣原理圖中電器元件均處于自然狀態(tài)。

　　

【正文】 ive of Shanghai than this bridge, which appears in quite a lot of movies about the city. Dozens of couples visit every day to pose for their prewedding photos on the bridge where Suzhou Creek begins and interconnects with Huangpu River. This is Waibaidu Bridge, or the Garden Bridge. The soontobewed couples pose in splendid attire on the bridge, leaning against the railing or sitting on the wooden floor. Some even risk walking into the middle of the road to get the perfect lights illuminate the bridge throughout the night, making it a picturesque place for prewedding portraits and lovers to meet. Constructed in 1873 and designed by a British pany, the 106meterlong bridge was the firstever major bridge in Shanghai. In 1856, the first large wooden bridge, Wells Bridge, was built over Suzhou Creek but the bridge toll led to plaints from citizens. So 17 years later, another wooden bridge, which did not require tolls, was built. People called it Waibaidu, which means “going across for free”. The bridge was renovated as a steel truss structure in 1907. Because nearly 40 bridges have now been built over Suzhou Creek, the bridge is no longer a traffic artery but is more of an observation deck for tourists. It is a tradition in Shanghai for a grandmother to walk across a bridge with their grandchild when he or she reaches one month. This represents that the newborn has overe all the twists and turns and its journey will be safe and smooth throughout his or her life. Waibaidu Bridge is always the best option because it’s the icon of Shanghai. The picture of my daughter when she was a baby held by her grandmother was also taken here. It’s like a family tradition, says Wang Xuefen, a Shanghai native who has a newborn grandson. Changning Riverside There is a 5km stretch of waterfront by Suzhou Creek in Changning district on Changning Road from the intersection of Hami Road to Jiangsu Road. It has bee a popular place to take a walk and sunbathe on the lawn. There is an overpass at the intersection of Changning Road and Gubei Road for people to enjoy the view of the creek and a 3 km plastic runway on both sides of Changning Road, which attracts people of all ages, Chinese and expat. Jogging on the two sides gives a different feeling because the north side is next to the creek, and the south side is adjacent to the residential highrises, which is like jogging in the jungle, says Xiao Xu, a 27yearold woman who lives nearby. The riverside used to be pletely different. Dozens of textile mills, chemical plants and machine manufacturing factories were set up along the creek in the 1920s. They brought industrialization but also pollution. From the 1930s the creek could no longer be used as a source for tap water, and no living fish or shrimp could be found. Suzhou Creek in my memory is dark and smelly. I used to go to the riverbank to watch the sewage disposal running out from the chemical plants when I was a little girl. We didn’t know it was pollution. We thought it was a red waterfall, says Huang Qi, a 57yearold Shanghai resident. So the residential houses along the creek were unpopular, and only migrants with low ines would live in that area, she says. However, things have changed. The plants were closed and turned into riverside parks and the apartments in the new highrises, especially those facing the creek, are much sought after. East China University of Political Science and Law This is the famous former Saint John’s University, China’s firstever modern institution of higher education established by missionaries from the United States in 1879. The buildings bine Chinese and Western elements. Address: 1575 《 機電控制與可編程控制器 技術(shù) 》形成性考核冊 26 Wanhangdu Road, Changning district The old residential area After you leave the university from its east gate you will enter a shabby neighborhood that retains its original look. The alleys are narrow and the houses are overcrowded. Some things have not changed for many generations, such as raising chickens at home. Address: West Guangfu Road Moganshan Road This is an artsy street that has bee very popular among artists and fashionistas in recent years. Graffiti covers the walls on the winding street, where you can find a cluster of art galleries and creative industry offices. Sihang Warehouse Four banks jointly funded the construction of this warehouse, so it is named sihang, or four banks. The warehouse, built in 1931, was used for the storage of food, firstaid supplies and ammunition during the years of war. The building, which is also a masterpiece left by the Hungarian architect Laszlo Hudec in the 1930s, has been recently transformed into a center of creative industry workshops. Address: 1 Guangfu Road, Zhabei district