毕业论文基于PLC液位控制系统设计说明书1.doc

无 锡 职 业 技 术 学 院 毕业实践任务书 课题名称 基于PLC的液位控制系统设计 指导教师 职 称 指导教师 职 称 专业名称 生产自动化 班 级 学生姓名 学 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、变频器、压力传感器配电装置以及水泵 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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 e