Design of a mixed distributed computer control system

In the field of industrial automation, fieldbus is changing the traditional DCS´s important position and the architecture of distributed computer control system. However, it is not the time that fieldbus is popularized widely in China because of the factors of economy, technology and industrial automatic level. Therefore, this paper presents a mixed distributed computer control system that is composed of fieldbus and RS485 communication protocol. Through fieldbus and RS485, process parameters and status information of field devices are delivered to monitoring computer. In addition, the information integration between control system and management system is achieved using ODBC technology. This system has already been implemented on the product line in one large-scale tobacco group successfully. The performance results show that the system exerts the advantages of both Fieldbus and traditional data bus adequately, and has many advantages, such as openness, reliability and high ratio of capability-to-price.