| PROFIBUS has been widely used among all existing fieldbus standards because of its better real-time in communication, high transmitting rate, low cost, flexibly topological structure, high redundancy and applicability in all kinds of industry control fields. PROFIBUS includes PROFIBUS-DP, PROFIBUS-PA and PROFIBUS-FMS. And PROFIBUS-DP, which is used in the control system of device-level and distributed I/O communication, is the market leader in fieldbus technology.At present, the main application and research on PROFIBUS-DP in our country is mainly in the system integration and engineering applications. A lot of low-layer equipments and intelligent instruments with PROFIBUS-DP interface are provided by foreign companies, which monopolize the instrument and equipment. Therefore the price of the whole PROFIBUS-DP fieldbus system is increased, and hampers its application and development in our country. Consequently, it is very important to develop PROFIBUS-DP communication interfaces with the property right of our own and intelligent slavers fitting to our country's fact.According to the application and current status of fieldbus in our country, the paper introduces the realization of a PROFIBUS-DP slaver from hardware and software using 80C52 MCU and communication interface chip (SPC3) based on the basic theory of PROFIBUS-DP fieldbus (including system composing, protocol structure, data access mechanism and slaver communication principle). The slaver's function includes as follows:â‘ Connecting common instruments to the PROFIBUS network using PROFIBUS-DP communication interfaces.â‘¡Including a PID control arithmetic module in the intelligent slaver, receiving the configuration information from the upper machine. The configuration of each arithmetic module is realized by MCU to make sure the general control in the fields.â‘¢There is analogical I/Os in the PROFIBUS-DP intelligent slaver besides digital I/O. The main character and innovation point in the paper is that PID control arithmetic modules are integrated in the PROFIBUS-DP intelligent slaver to improve its function and provides a new method to its further development.Finally, it designs a platform including a master and a slaver according to the actual condition, to test the whole system and achieve the expected results. |
