Design And Implementation Of Distributed Control System Based On Embedded Soft PLC

In recent years, developed countries in Europe and the United States have launched some development plans of manufacturing industry, the aim is to enhance the competition of their manufacturing industry and lead the trend of industrial development, Industrial 4.0 of Germany is the most representative plan. Industrial 4.0 is dominated by intelligent manufacturing, and intelligent plant will be the key to the future industrial system, then the control system and control equipment in the workshop must be adjusted to the demands of intelligent plant’s development. The control system in industrial field has the followings, Distributed Control System(DCS), Programmable Logic Controller(PLC) and Fieldbus Control System(FCS), and the former two have widely used, therefore, it is significant that designing and improving the existing equipment as well as control system based on DCS and PLC to adapt to the demand of intelligent control.According to the research on the technology of industrial control system, this thesis has designed an embedded soft PLC and expand the networking capabilities, it can be as the underlying controller, interconnected PLC devices through the CAN bus, constituted a distributed control system by the Ethernet. The system includes development system and running system, this thesis describes the design and implementation of latter, and the main work is as follows:Firstly, we have analyzed the system structure and working principle of traditional PLC, and the control systems based on PLC, and then have studied the implementation scheme of the embedded soft PLC in the DCS.Secondly, we have designed the overall structure of the running system with the specific hardware and system processes. We describe the device interface of hardware platform, the structure and each function module of software platform.Thirdly, we have completed the modules of software platform, including the following: real-time operating system, communication interface, device driver, application program tasks, system initialization. The application program tasks are the key of running system, one of them is the circular scanning task, and it is in the light of the user control program to achieve the control functionality. In addition, we have introduced the implementation procedure of the embedded soft PLC’s instruction system in detail, design and achieve the soft components of PLC, and give an example to illustrate the process of the 27 basic logic instructions.Finally, we have designed a simple distributed control system,by functional testing and integration testing of the embedded soft PLC’s running system, verify the control function and the interface of system is corrected.