太阳能热水器控制系统设计.doc

摘 要 现在，城市居民绝大部分都使用了太阳能热水器，农村也有相当一部分人使用。太阳能热水器在国内外的应用越来越广泛，它的发展也越来越迅速，而且，人们对太阳能热水器的要求也在提高。因此，研究和开发先进的太阳能热水器控制系统变得越来越重要。 本设计进行了系统的I/O分配和PLC选型，以及对各所需器件的选型，对输入输出点进行了统计，共有21个输入输出点，根据PLC的选型原则，设备选用了在生产中应用最为广泛的西门子公司生产的S7-200系列(CPU226)的PLC。根据要求设计出了控制系统电气原理图和接线图等，控制系统对温度的调节采用调功器实现。还对控制系统的软件程序进行了设计，即水温、水位等控制程序的流程图，根据控制系统软硬件设计和控制要求，在介绍了PLC的编程方法的基础上，设计了太阳能热水器控制系统的梯形图。最后还对可编程控制器（PLC）的安装、维护和检修做了简单的设计。把PLC作为太阳能热水器的控制系统，充分利用了PLC的特点，大大减少了其它元器件的使用。它使系统接线简单，检修维护方便快捷，增进了系统的先进性。 关键词：太阳能热水器；PLC；控制系统 Abstract Now, vast majority of urban residents use solar water heaters, rural areas have a considerable number of people using it.Solar water heater is widely used at home and abroad,It is developing more and more rapidly, people on the solar water heater should be improved.Become the research and development of advanced solar water heater control system is more and more important. In this design, the address of I/O is resigned and the suitable PLC is choosed,and the selection of the needed devices,The input and output points to the statistics, a total of 13 input and output, the PLC in accordance with the principle of selection, equipment selection in the production of the most widely produced by Siemens S7-200 series (CPU226) of the PLC.The electrical principle diagram and the interconnection diagram are designed, according to the requirement,control system of the temperature regulating the power regulator to achieve.The control system software program design,the water temperature, water level control program flow chart,in accordance with control system software and hardware design and control requirements, After the introduction of the PLC programming methods,designed of ladder diagram of the solar water heater control system.At the end of the programmable logic controller (PLC) installation, maintenance and repair to do a simple design.As the controlling system of solar water heater, PLC greatly reduces the number of other components,it makes full use of the characteristics of PLC. Moreov