| According to the development plan of information industry, China's industrial control machine industry will reach 100 billion in output value. And the development priorities is: the transformation of traditional industries to adapt to the demand ,vigorously promote the PLC, embedded industrial computers industrial production, focusing on development and production of their own intellectual property rights of the DCS and FCS, so that made the brand more than 50% market share. It can be foreseen that with the rapid development of power, metallurgical, petrochemical, environmental protection, transportation, construction and other fields during the "Eleventh Five-Year" period, and their demand for IPC will be gradually increased, IPC will have a great prospect for the development of the market.Since 1983, industrial control computer is included in the national popularity of computer-based series development planning, China's industrial machine has gained rapid development, lots of 1 technology product already mature and applied in every field, some already can compete with abroad product, particularly in DCS and IPC, as well as some embedded control fruits.DCS is currently in a prime market, specially domestically produced DCS has obtained the user's approval, this is different from the PLC market which fully imported products. Moreover the DCS technical gradually maturing, reduce the technical threshold, quickly produce the products can open up the market. Although DCS will eventually develop to the FCS, but this will not be the short time can achieve, especially the massive field apparatus which is impossible to reform into fieldbus intelligent devices in a short time. The research and develop of DCS also provide a foundation for FCS to produce higher products in the future .We designed a complete communication module to realize data communication connection between master control card and each 10 card in the entire DCS system. From small and medium-sized manufacturing point of view, the agreement serviceability is important, but, how to grasp the agreement to produce products by the quickest speed and the stable quality seems more important. We try to make a balance p between the technical sophistication and the product total cost that is pursues the performance price to compare the maximization. DCS system designed primarily to manufacturing processes, real-time requirement is not very high, the amount of data is not very large, so MODBUS already enough to use, therefore we have chosen the second set of plan. The module used the electrical specifications of RS-485 protocol, software communication protocol for the MODBUS protocol, the entire system had characteristics with the lower cost, faster and far-distance communications and so on. Simultaneously the system used a two-circuit redundancy design to avoid interference caused by the issue of data loss in maximum limit. Because the DCS system requires very high stability, therefore all equipments must carry on the redundant backup basically to guarantee the entire system can operate normally when one system broken. At the same time, when data transfer error occurrent, avoid the in once more reissues which influence next scanning and guarantee real-time system. We use the W77E58 MCU which produced by Winbond Company as CPU, the single-chip with advanced fifty-one core increased the running rate largely when instructions situation was invariable. 485 correspondence chips have used American MAXIM Corporation's MAX1487 chip which had a quarter of unit load receiver input impedance that the main line can take up to 128 pieces I/O board cards. |
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