The Design And Realization Of Intelligent Circuit Breakers Control System Based On Devicenet Field-Bus

DeviceNet bus is an open, low-cost and high performance substrate network control technique based on CAN bus,which provides very important device-level diagnosis function as well as improves communication between equipments and has been paid attention to by more and more enterprises.Transforming or getting rid of those old equipments in a short time is unrealistic because large amount of instruments are based on serial communications technique at the moment.So it is in need of reality that instruments with serial ports are applied to DeviceNet bus.(1) It is said that developing intelligent circuit breaker supervision system based on DeviceNet bus has important realistic significance through the analysis of fieldbus development and the comparison of several popular fieldbus standards.The current situation of study on intelligent circuit breaker supervision system is described and the developing trends of intelligent circuit breaker supervision system is pointed out.(2)Protocol specifications of DeviceNet are deeply studyed.Display message format of DeviceNet protocol specifications,I/O message format, DeviceNet object model, Display information connection mode, I/O message connection mode and predefined master-slave connection mode are introduced in detail.(3)The overall design of intelligent circuit breaker supervision system based on DeviceNet is given.The structure of supervision system and its working principle are described. DeviceNet communication adapter is designed and achieved that the hardware construction principle and design implementation method of the CAN communication module,serial communication module, power supply circuit, parameters setting circuit and state performance circuit are discussed in detail.(4) DeviceNet communication adapter software is designed and developed based on hardware platform. DeviceNet communication adapter software mainly uses object-oriented programming method,which completes the functions of initialization of chipset registers,sending repeated MAC ID checked request message, distributing predefined master-slave connection group and I/O polling information connection communications and so on.(5) Design and realize the supervision system software.The software have DeviceNet master fuction、DLL fuction、draw dynamic curve fuction、view division、 the timer program fuction and etc. The final running results indicate that the designed supervision system can achieve the real-time monitoring of intelligent circuit breaker. The designed DeviceNet communication has been through ODVA conformance testing in shanghai conformance testing center.The whole supervision system runs stably and functions well, meets the design expectations.