Design For Assembly Valve Controller Based On DeviceNet Fieldbus

DeviceNet is one of the low-cost and high-capability Fieldbus which based on Control Area Network technology. It's physical layer and data link layer in accordance with CAN 2.0 protocol, data link layer protocol was realized by CAN controller. Each device within a DeviceNet network is represented by object model, each object in model was represented by class-instance-attribute. With the Predefined Master/Slave connection set identifier, DeviceNet can simplify the exchange of I/O and explicit message, I/O message is used to the data correlation with control and real-time message, explicit message carry the configuring and diagnosing data of nodes.Based on Group2 Only Server, the paper analyzes the process of communication between Master and Slave, from Application Layer in details according to the DeviceNet Specification. This dissertation concentrates on the development of assembly vavle controller based on DeviceNet. Starting from the bottom DeviceNet protocol and based on a deep understanding of the protocol, the interface driver, the protocol stack and application routines which realize DeviceNet specification are successfully programmed. This thesis introduces the current development of fieldbus technology and several popular fieldbus standards; describes DeviceNet specification with an emphasis on its communication protocol including object model, object class, message, device profile and predefined master/slave connection set; constitutes a technical requirement of a general DeviceNet communication interface for slave device; and finally designs realizes the comuunication interface.The laboratory experiment proves that the developed DeviceNet communication interface for slave devices fully realizes the specified technical requirement. Its communication mechanism complies with DeviceNet protocol. Connected to DeviceNet network, it can reliably commnunicate with DeviceNet Filedbus module of PLC from OMRON Automation. The Ethernet interface can transmits data to upper PC. The assembly vavle controller meets the market requests. It has broad application prospect.