Design Of The Master Node Of The Fieldbus Control System Based On ARM

Fieldbus technology with its advantage of nature,practicality,reliability, openness,has become a hotspot of automatic technology.Fieldbus control system as an open,with the interoperability and thorough dispersion of control system has been a great impact to the traditional PLC,distributed control system.It must have a broad prospects for development.As one kind of the fieldbus bus,CAN-bus with its high reliability,real-time, cheap prices,easy to implement,are widely used in the field of industrial control. With the compare of traditional control systems,industrial control system based on the CAN-bus can reduce the complexity of system,and costs,improve system stability and expansibility.The fieldbus control system is designed for the specific applicational requirements of a stone processing plant.Based on the analysis of CAN bus protocols industrial control network solution is given,including master node hardware design, software design,human-computer interface design,network communication structure and the flow chart.The major work of the paper is as follows:First,hardware and software platform is designed.Based on the ARM processor LPC2378,the haedware of a master node of the industrial control network is designed. The design of the hardwares include the CAN bus interface circuit,serial interface circuit,analog-to-digital conversion circuit,digital-to-analog conversion circuit.Then,theμC/OS-Ⅱoperating system is transplanted onto on the master node. Based on the operating system,drivers for the hardware modules are designed, including serial interface and CAN module initialization,data receiving and Sending.Second,according to industry specific needs of control applications,a network solution is designed,including network topology programs,communication structures.Based on the CAN2.0B protocol a technical specifications for the application layer of the CAN bus network is established.The protocol named CAN₀8, using extended frame format.Third,based on the eView MT505,a human-machine interface is desiged.The communication between human-machine interface and the master node is achieved through Modbus.