Design And Implementation Of Devicenet Communication Adapter

DeviceNet fieldbus as one of the international standards, has gradually become the focus of attention of the field of automation Therefore, research and development technology, deviceNet Bus-based communication adapter is very urgent and necessary. In-depth study on the basis of the DeviceNet protocol specification, designed using the realization of the CAN controller SJA1000DeviceNet Communication Adapter. The basic functionality of the DeviceNet protocol for data exchange between the equipment and the corresponding controller. In this way, DeviceNet can either work in the main mode, can also work in multi-master mode.In-depth study of the DeviceNet protocol specification based on, in this thesis, the communication device node hardware system design. DeviceNet bus based on CAN, CAN port communication in the design of the application layer before test. Application layer protocol is the use of the Philips company SJA1000CAN controller chip,and a brief description of the SJA1000controller and associated devices. According to the protocol specification and application of the relevant requirements of the circuit, according to the relevant requirements of the protocol specification and application circuit, design the power supply circuit, the coupler isolation circuit and watchdog circuit, TJA1050bus transceiver DeviceNet bus physical interface. In this thesis, a communication adapter to connect from the station communication interface hardware schematic, complete the welding of the PCB board design and hardware board, and through debugging.In this thesis, software design is used in the Keil environment C51language to achieve. The use of object-oriented programming has prepared the DeviceNet data link layer and application layer program. For the initialization of the controller SJA1000and interrelated parameters, interrupt processing, basic functions such as receiving and sending of CAN messages and duplicate MAC ID detection in accordance with the DeviceNet application layer protocol specification predefined main from the connection configurationI/O message receiving and sending, polling and bit strobe both data trigger mode communications. Therefore, this communication is established based on connection-oriented (point-to-point or multicast) communication model.In order to verify the functionality of the DeviceNet communications adapter developed in the paper. Hang it on the Rockwell Automation AB PLC. Use Rockwell supporting software RSLogix500paper design of the communication adapter configuration and debugging. Through the testing of the software it, monitoring software, the MINI the CAN get the host computer and communication analysis of the data communication adapter, and prove a thesis developed DeviceNet communications adapter to communicate with the master, achieve all kinds of predetermined functions.