Research On The Control Network Based On Token Mode

According to country's continual development strategy and continuous strictly executive environmental protection policy, small chimney in city will be removed in success. It will be replaced by high level automatic central heating boiler house. Thus it is important to make sure central heating boiler's safety, economical and efficiency running. At present domestic control system of central heating boiler can be classified to circuit detection control, centralized control and adopting intelligent meter to data acquisition and control scheme according to system establishment scheme. But these schemes have several shortcomings.With the continual developtment of mordern network control technology, take it into central heating boiler control system, it can enhance control quality and realize the function which is difficult to achieve by traditional control technology. This thesis designs a communication network based token to realize data acquisition and control of boler production field. At first considering network structure, it adopts RS-485 serial bus which has the merits of simple structure, easy network establishment, strong anti-jamming capacity, high transimission speed and far transimission distance as the physical layer, the data acquisition and control meter connect in series to monitor the boier plant. This can save cost of cable and installation, also it is convenient to plant installation. In addition token bus network combines the meits of token style with the topology structure of bus, it can satisfy the requirment of real time and reliability of industrial process control, thereby it turns into the main trend of industrial control network. Adopt standard Modbus protocol as communication protocol, and realize token communication by extending user facility. Overcome the disadvantage of risk centralizing of past main-slave communication and centralized control mode, make the control of boiler system more agility and credibility. The control sytem can realize network data acqusition and control by communication of intelligent meter, it doesn't limited by single meter.