毕业设计-基于PLC的液位控制系统设计.docx

无 锡 职 业 技 术 学 院 课题名称  基 于  毕 业 实 践 任 务 书 P L C 的 液 位 控 制 系 统 设 计 指导教师 指导教师 专业名称 学生姓名  生产自动化  职 职 班 学  称 称 级 号 实习单位 课题需要完成的任务： 利用信捷 PLC 设计液位控制系统，完成如下任务： 通过触摸屏、可变程序控制器变频器（PLC）、压力传感器、配电装置以及水泵实现液 位控制系统的设计 确定控制方案，选择 PLC 型号，定义输入/输出，画出 PLC 端子接线图。 进行软件编程、完成控制梯形图并完成调试。 课题计划： 10 年 2 月 26 日-----10 年 3 月 10 日 确定毕业设计课题 10 年 3 月 11 日----- 10 年 3 月 22 日 调查参观、完成调研报告 10 年 3 月 22 日-----10 年 3 月 31 日 确定方案，完成方案论证 10 年 4 月 1 日----- 10 年 4 月 20 日 设计电路，编制程序，完成论文 计划答辩时间：10 年 4 月 21 日-----10 年 4 月 30 日 自动控制技术系  系（部、分院） 2010 年  4  月  26  日 无锡职业技术学院 毕业设计说明书（英文翻译） PLCs --Past, Present and Future Everyone knows theres only one constant in the technology world, and thats change. This is especially evident in the evolution of Programmable Logic Controllers (PLC) and their varied applications. From their introduction more than 30 years ago, PLCs have become the cornerstone of hundreds of thousands of control systems in a wide range of industries. At heart, the PLC is an industrialized computer programmed with highly specialized languages, and it continues to benefit from technological advances in the computer and information technology worlds. The most prominent of which is miniaturization and communications. The Shrinking PLC When the PLC was first introduced, its size was a major improvement - relative to the hundreds of hard-wired relays and timers it replaced. A typical unit housing a CPU and I/O was roughly the size of a 19 television set. Through the 1980s and early 1990s, modular PLCs continued to shrink in footprint while increasing in capabilities and performance (see Diagram 1 for typical modular PLC configuration). In recent years, smaller PLCs have been introduced in the nano and micro classes that offer features previously found only in larger PLCs. This has made specifying a larger PLC just for additional features or performance, and not increased I/O count, unnecessary, as even those in the nano class are capable of Ethernet communication, motion control, on-board