Research And Development On FCS Based On CAN Bus And Modbus/TCP

As an advanced industrial control technology, fieldbus introduces network communication and management to industrial control field. By using fieldbus as a nexus, fieldbus control system converts a single distributed surveying control equipment to be a network node, they can communicate with each other and finish automatic control task together.This paper reviews the developing history of industrial control,introduces the concept of fieldbus and summarizes the features and architecture of fieldbus control system. By using CAN bus which is one of the most promising fieldbus constructs the monitoring network and using Modbus/TCP which is an industrial ethernet protocol constructs the information network, we present a FCS scheme suitable for minor industrial enterprises. The monitor network is a CAN based distributed structure comprised of master and slave station. Slave station consists of several fieldbus modules such as digital input modules,digital output modules,analogue input modules,analogue output modules. The hardware of master and slave modules uses embedded ARM processor with CAN controller as their core CPU and uses the real time operating system——μC/OS-Ⅱas their software designing platform. Master station provides ethernet interface and uses Modbus/TCP protocol to connect device network and information management network, realizes data exchanging and be convenient for scheduling and monitoring.Finally, through the practical application in the friction-style automatic conveyor system of the car assembly line, the effectiveness and reliability of the functions of the self-designed fieldbus control system based on CAN bus and Modbus/TCP protocol are verified. The practical application proves that the self-designed fieldbus control system has features such as easy-fit,low-cost and high-expandability.