Research Of Fieldbus Profibus-PA Technology And Development Of PA Device

PROFIBUS is one of the fieldbus standards and it is international, open and independent of device manufacturer. It is applied widely in mechanical manufacture, process control and building automatization etc. PROFIBUS-PA instruments applied in process control are key device in fieldbus control system, supplied power with data bus, achieved cooperation among them made by multi-manufacture and applied in explosive area. Market demand for them is very large.The key technology of developing PROFIBUS-PA device is lucubrated, which include the following parts: IEC61158-2 transport technology is used in physical layer, which improved fieldbus communication reliability by using bit synchronization protocol and Manchester double direction L coding. Communication protocol should achieve essential DP function and extended DP function (selectable). The data transmitted should follow PA profile, by which cooperation among field devices can be achieved.I had acquired the main achievement in the paper as following: Under the current technical conditions (chip, software, technical support) in China, feasible solutions of developing PA device are brought forward and PA prototype is designed. The prototype has achieved Long-distance power supply by data bus, IEC61158-2 transmission technology and essential function of PROFIBUS-DP and can be connected to DP fieldbus system for transparent communication between the two sort of feildbus segment by DP/PA coupler and can be communicated with the DP master inerrably and continuously according to the primary PROFIBUS-DP communication protocol and process realization of state machine. This prototype has achieved expected target. This will promote the autonomous development of PA instrumental device in China.In addition, the experience accumulated in the process of the choice of design scheme, the developing and debugging of software and hardware is also a sort of achievement.