| The Remote Terminal Unit(RTU) is a general industrial process control product widely used in the field of industrial automation. The project source of present paper is a college-enterprise-cooperation project to design a small and economized Mini RTU with the autonomic intellectual performance and apply to the cooperative enterprise engineering and product promotion.According to the technical requirements of customers, a new generation of MCS-51 micro controller of series STC12C5 A is used as a core to design hardware platform, and process design is made by installing support of standard rail. The RTU is supplied by 24 V DC power, which achieves data acquisition and safety monitoring in industrial field, as well as 8 DI、8 AI、4 AO、8 DO process channel. A RS-232 interface is designed for software download and super terminal communication, and a RS-485 and an Ethernet interface are designed for external computer communication. In view of using environment, industrial grade chips are used in hardware platform to ensure the product working in environment temperature of-40℃~+80℃. Anti-electromagnetism interference is specially designed to ensure the product working in bad electromagnetic environment steadily and reliably. Based on the foreground and background software framework, the software of RTU is designed to achieve data acquisition、the output control and transmission function of data communication with external computer. As a result, the RTU designed in present research is of perfect function, strong anti-interference ability and application value.The key technique of this project is anti-interference design. Process control products operate in harsh environment with heavy electromagnetic interference. According to user’s requirements, the designed product should have the ability to resist the industrial grade 4 electromagnetic interference. To solve the problem, shielding measures are used in input power, I/O process channels, communication channels and the Status indicator in the design of hardware platform, and enough creepage distance is used as well.After the completion of theory design, installation and commissioned, design of real-time multi-task software, and test of function and property in cooperative enterprise laboratory have finished. The test results show that the function and property of designed RTU meets the requirements of customers. |
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