Design And Implementation Of RS232 /PROFIBUS-DP Slave Interface

PROFIBUS has widespread usage because it's advantages; such is better communication real-time character, high transmitting rate, low cost, topological structure flexible, high redundant, suitable for various kinds of industrial control field, etc. But, lots of equipment have only RS232 serial interface in traditional industrial process control area, such is data collector, executive component and controller. Because RS232 standard outputs signal is not compatible of the PROFIBUS, so RS232 interface equipment can't open interconnection and distributed control with PROFIBUS. Therefore have very important realistic meaning and project value to study this technology.The thesis regards solving RS232 interface equipment and PROFIBUS-DP interconnection as the direction of studying. Designing and developing has RS232 interface and PROFIBUS-DP interface Slave. Realize the protocol converted between RS232 equipment and PROFIBUS-DP .The main work of the thesis and achievement are summed up as follows:1,The core of studied PROFIBUS-DP technology forming, systematic structure, communication protocol, message structure and system characteristic, then put forward the technological scheme used protocol converted in RS232 and PROFIBUS-DP.2,Designed and developed has RS232/ PROFIBUS-DP Interface Slave. Analyzed and contrasted two kinds ways of realizing that the hardware protocol converted of " MCU +ASIC " and" software protocol converted of MCU ", determine adopted way of hardware protocol converted, selected SPC3 for use protocol converted chip in PROFIBUS-DP Slave Station. The core of Slave Interface hardware design regarded PHILIPS P89C668 MCU chip and SPC3 chip interface circuit as, and additional auxiliary interface circuit is formed.3,Realized the slave interface protocol converted software design. Adopt the module structure programming method, finished original procedure code developing and compiling, chaining, software emulating through KeiL C51 Windows integrated developing platform, carry on the emulation of the hardware to the original procedure code through MCU TKS668 hardware emulator based on KeiL platform.4,We set up PROFIBUS-DP Master/Slave test and debug system based on computer, use serial debug software simulation the data interchange from industrial process control system to RS232/PROFIBUS-DP Slave Interface, we realized two-way data communication finally through configuration Master and Slave in SOFTPLC, write GSD file and STEP7 communication program by myself design .5,The research results of the thesis use the prospect and value certainly. RS232 and PROFIBUS-DP protocol convert interface can embed in the process control equipment as Intelligent Slave Station, that realize many functions as data collect and control. Expensive bus gateway products that can replace in abroad after perfect Interface performance and industrialization producing have competitiveness of stronger market.