基于S7-300的烧碱系统的设计毕业设计论文.doc

北华大学毕业设计（论文） - PAGE 2 - 毕业设计论文 基于S7-300的烧碱系统的设计 摘　　要 在分析和研究烧碱系统中离心机控制系统的基础上，根据有些厂方工艺和现场生产的特殊要求，在了解了烧碱的生产工艺后，设计了离心机的PLC控制系统。离心机各个电磁阀的操作均由PLC控制，可以根据工艺要求可以实现电磁阀的动作。采用PLC控制离心机各电磁阀的动作，进一步降低了操作人员的劳动强度，提高了生产效率，并有效控制母液含盐量及析出盐含碱量。克服了离心机工作转速调节单一、故障率高等缺陷。 本文主要讨论了离心机及PLC的工作原理，以及运用梯形图编写PLC程序，对PLC逻辑控制程序的设计方法及实现过程、控制系统的优点及实现方法做了说明。深入了解了离心机的工作原理及其故障情况，对系统要求及参数进行研究分析，利用PLC自身所具备的逻辑运算和数据处理功能，实现了离心机控制系统的设计。本系统硬件结构简单，操作方便，直观性好，控制安全可靠，运行平稳，控制精度高，具有其他烧碱系统离心机控制系统所没有的若干优点，且经济实用，具有广阔的应用前景。 关键词： 关键词：烧碱生产；PLC；离心机；程序设计 Abstract On the analysis and study of caustic soda production system of centrifuge control system based on, according to some of the factory and on-site special production requirements, in the understanding of the caustic soda production process, design of centrifugal machine PLC control system. Centrifuge each electromagnetic valve operations are controlled by a PLC, can accord to process requirements can be achieved in the valve action. Using PLC control centrifuge each electromagnetic valve, further reduces the labor intensity of operators, improves the production efficiency, and effectively control the mother liquor of salt content and salt content. To overcome the centrifuge operating speed regulation of single, higher failure rate of defects. This paper mainly discusses the centrifuge and the work principle of PLC, and the application of ladder diagram PLC preparation procedures, to PLC logic control program design method and the realization process, control system and implementation method have been explained. A thorough understanding of the working principle of centrifugal and fault conditions, the system requirements and parameters analysis, using the PLC of its own with a logical calculations and data processing functions, realizes the centrifuge control system design. The hardware of the system has the advantages of simple structure, convenient operation, good visualizability, safe and reliable control, stable operation, high control precision, with other caustic so