PROFIBUS-DP Master Station Interface Technology Research And Product Development

PROFIBUS is one industry communication protocol established by Germany and Siemens. Presently, PROFIBUS has become one nation protocol in our state. PROFIBUS could be applied to various fields. PROFIBUS is divided into DP and PA bus. DP is used in dispersed industry control, and PA is mainly used in process industry with preventing explosion requisition. When PROFIBUS is running, master stations and slave stations communicate each other on PROFIBUS.As far as master station is concerned:1. Master station needs to have the function of cycle communication with slave stations. The cycle communication function is a basic function of master station exchanging data with slave station. Before master station join in data exchanging with salve station, master station needs to make slave station pass through diagnostic, parameter, configuration and second diagnostic state. Additional, master station is able to make slave stations achieve the function of global control. The four state, global control and the switch among them constitute the cycle communication function of master station.2. Master station must need to have the function of communication with other master stations, which is the token exchanging. The form of token loop, master station how to joining in bus, how to deleting failure master station, how to overcome noise to restore token exchange. These factors comprise the token state machine.As far as the manner of development is concerned:1. Adopting ASPC2 protocol chip as the development of master station. But ASPC2 only have physical layer. Then, data link layer and application layer are not contained in ASPC2. Siemens closes off the technology of master station. If adopting ASPC2, it must make so many problems.2. Adopting the microcontroller, which own large importation and large exportation buffers, such as AVR or ARM. Though the rate is limited, but microcontroller is able to accomplish a master station net card. If adopting microcontroller as master station chip, it requests that researcher must be very familiar with the schedule of the communication of master station and the control time parameters. Researchers must carefully read the protocol, and program a great deal of program. Enhance the requisition of researchers, but reduce the cost of hardwear.The communication of master station net card symbolize the achieving of the communication schedule of master station.