【正文】 end of its development ,emphasis on analyzing the methods and problems faced in the temperature control of the production process. The accurate control of the temperature of the mold and dies of the extruder is one of the important technologies which related to the quality and performance of parameter time varying, large time delay and strong coupling. In this paper it used the adaptive setting strategy which bined with conventional PID . Based on the requirements of the production process of the film, the BOPP film production control system is designed which based on the field bus technology, and the system is of functions of detection ,control and management. After transformation, the system is a level 2 process control system. It used S7300 PLC produced by Siemens panies for the basic automatic control which realizes the control of the requipment running like the heater, the draw machine ,the tractor. As well as it used industrial puter produced by advantech . for the monitoring station which is used to plete the functions of monitoring, alarming and tabulation. Also the operation of the system is very simple, the picture innervation is visual, control effect is well, the reliability and the stability have greatly improved. It is proved by long time running that the equipment running well, the mainrenance cost decreased, the product quality improved and enterprise economic benefit increased. Key Words: interchange, PLC, frequency, Feedback 桂林電子科技大學(xué)畢業(yè)設(shè)計（論文）報告用紙 目 錄 .............................................................................................................................................................1 ...........................................................................3 雙向拉伸薄膜生產(chǎn)線的工藝流程 ...........................................................................................................3 平面雙向拉伸聚丙烯薄膜的生產(chǎn)設(shè)備 .................................................................................................3 干燥 .................................................................................................................................................................3 擠出機 ............................................................................................................................................................3 過濾器 ............................................................................................................................................................4 擠出機機頭 ..................................................................................................................................................4 冷卻裝置 .......................................................................................................................................................4 縱向拉伸機 ..................................................................................................................................................4 橫向拉伸機 ...................................................................................................................................................4 廢料回收 ........................................................................................................................................................4 雙相拉伸塑料薄膜生產(chǎn) 線拉伸方法 ......................................................................................................4 交流變頻調(diào)速 ...................................................................................................................................................5 交流調(diào)速系統(tǒng)的發(fā)展 ...............................................................................................................................6 變頻調(diào)速的現(xiàn)實意義 ...............................................................................................................................6 變頻器的結(jié)構(gòu)和工作原理 .....................................................................................................................6 變頻調(diào)速的基本控制方式 ..........................................................................................................................7 V/F 控制方式 ..............................................................................................................................................7 轉(zhuǎn)差頻率控制 ..............................................................................................................................................8 PWM 控制 ........................................................................................................................................................9 矢量控制 .......................................................................................................................................................9 PROFIBUS 工業(yè)總線 .................................................................................................................................... 10 ..............................................................................................................................11 縱拉部分工作原理 .......................................................................................................................................11 PLC 控制接線圖 ............................................................................................................................................ 13 縱拉機設(shè)備選擇 ........................................................................................................................................... 15 導(dǎo)線選擇 .......................................................................................................................................................... 16 平面雙向拉伸聚薄膜生產(chǎn)線縱拉部分電氣原理圖設(shè)計及實現(xiàn) ............................................ 17 PLC 控制系統(tǒng)設(shè)計 ..................................................................................................................................... 17 PLC 控制系統(tǒng)設(shè)