Research On Key Technologies Of Block I/o Base On Profibus-dp

Fieldbus developed rapidly in recent years, it provide an efficient, reliable and economical solution of digital communication among intelligent instruments, controllers, implementing agencies and other devices. PROFIBUS fieldbus has high transmission speed up to 12Mbps. PROFIBUS includes PROFIBUS-FMS, PROFIBUS-PA and PROFIBUS-DP 3-compatible components.PROFIBUS-DP is mainly used for digital signal transmission between central control units and decentralized I/O devices. With characteristics such as high-speed transmission, low price and simple install, PROFIBUS-DP is highly valued by a large number of corporations.After studying PROFIBUS-DP protocol, transmission technology and mechanism of data accessing, this paper presents a development of PROFIBUS-DP intelligent slave station using P89V51 and ASIC SPC3 which has PROFIBUS-DP communication interface.BLOCK I/O module has the capability of communicate with PROFIBUS-DP devices. It has 8 digital signals input or 8 digital signals output; the equipment interfaces have short-circuit protection and it can provide diagnostic information; the LED can indicates bus and power status.The study of this paper includes:(1) Study PROFIBUS-DP protocol, especially protocol of data link layer;(2) Study the structure of ASIC SPC3, to understand the communication process of SPC3;(3) Design the interface with short-circuit protection and diagnosis;(4) Complete programming of software to achieve PROFIBUS-DP communication. GSD document also should be done;(5) Build a PROFIBUS-DP system, use PLC as PROFIBUS-DP master station, test BLOCK I/O's communication and complete the other tests.Finally, the works of this paper were summarized, and the research work in the future was proposed.