| The Fieldbus is a rising technology,which appears with the development of digital communication , computer technology , automatic control , network technology,intelligent instrument and modularized integration.It is a fully decentralized, all-digital,intelligent,intercommunication,interconnection,multi-variable, multi-node serial communication technology used between field instrument and controller.The fieldbus control system based on fieldbus technology has been becoming the trend of the development of automatic control.PROFIBUS-DP is mainly used for communication between field devices,and has the higher real-time.PROFIBUS-DP intelligent node can link standard signals of DCS to FCS to realize their seamless integration,therefore the application of PROFIBUS-DP intelligent node has a wide prospect.Baised on studying the PROFIBUS-DP theory and the work mechanism of the slaver,this thesis not only introduces he software and hardware design method of PROFIBUS-DP intelligent node,the compiling method of the node's GSD file,but also builds the hardware testing platform based on the master of CP5611 and the slaver of intelligent node.The design of hardware mainly includes the circuit of data_acquisition and the communication interface circuit of PROFIBUS-DP.The thesis accomplishes the design of PROFIBUS-DP communication interface circuit by using AT89S52 MCU and siemens'SPC3 protocol CMOS chip,Data_acquisition circuit converts 4～20 mA analog signals into 1～5 V,insulates them by linear optoelectronic isolator,digitizes the field signals by 12 bits A/D convertor and then sents them to the MCU's memory.The software design of the node mainly includes the initialization and interrupt processing program of SPC3 and it also includes the data_aquisition program.The thesis puts emphases upon the initialization and interrupt processing program of SPC3.The initialization program mainly sets the interior 64B register of SPC3,so as to sets the work mode of SPC3 and confirms the capacities of input,output, and diagnosis buffer and the radical finger.The interrupt processing program deals with the new reports.Finally,the software design cooperates with the specific applicable program to implement the design of Modular PROFIBUS-DP intelligent slaver.The thesis configurates the hardware and software of the master and slaver by using the configuration software of STEP7, WINCC and SIMATIC NET,and tests the developed DP node by the simple PROFIBUS-DP fieldbus control system which includes single master and slaver. |
