基于PLC的电厂输煤系统设计.doc

摘 要 由于PLC程序的复杂性不断提高，因此在这个领域中对于这种方法的应用的兴趣越来越高。正式的方法对于系统在验证和确认的属性方面有着严格的证明。应用这种正式方法的一种方法是在可编程逻辑控制器中利用一种正式的设计方法。然而，对于现有的软件，必须优化，改变或者移植到新的系统。现在还需要一种方法可以由一个给定的可编程逻辑控制器开始。因此，PLC程序的规范化是当前研究的一个主题。这篇文章概述了一个基于逻辑可编程控制器重建方法。转换成厂商独立的格式可编程逻辑控制器结构的可视化被认定为是这一过程中间的一个重要步骤。同时也展示了如何使用XML及相应的技术将现有的可编程逻辑控制器正式化与可视化。 传统的热电厂输煤系统是一种基于继电接触器和人工手动方式的半自动化系统。由于输煤系统现场环境十分恶劣，不仅极大损害了工人的身体健康，而且由于输煤系统范围大，经常有皮带跑偏、皮带撕裂及落煤管堵塞等等麻烦，大大降低了发电厂的生产效率。随着发电厂规模的扩大，对煤量的需求大大提高，传统的输煤系统己无法满足发电厂的需要。 本文在充分考虑输煤系统的作用和运行可靠性基础上，设计了一条具有两个部分的输煤系统，从结构上保证了输煤系统的运行可靠性。根据输煤系统范围大、运行方式多，提出了基于台达公司PLC的输煤控制系统实现方案，该方案不仅降低了开发的工作量，而且降低了维护的工作量，同时也以后的升级提供了条件。 关键词：PLC；输煤控制系统；可编程序控制器 ABSTRACT Due to the growing complexity of PLC programs there is an increasing interest in the application of formal methods in this area. Formal methods allow rigid proving of system properties in verification and validation. One way to apply formal methods is to utilize a formal design approach in PLC programming. However, for existing software that has to be optimized, changed, or ported to new systems there is the need for an approach that can start from a given PLC program. Therefore, formalization of PLC programs is a topic of current research. The paper outlines a re-engineering approach based on the formalization of PLC programs. The transformation into a vendor independent format and the visualization of the structure of PLC programs is identified as an important intermediate step in this process. It is shown how XML and corresponding technologies can be used for the formalization and visualization of an existing PLC program. The traditional coal transfer system of power plant is a half-automation system based on relay connect and manual work. As the environment of the coal transfer system is so execrable, it not only does harms to the workers health but also has problems like belt slide,belt avulsion,and jam of the coal-falling pipe and soon for its large scope. This sharply decreases the productive eficiency of the power plant. Along with the dev