Research and development for the communication interface conversion of Profibus and CAN bus

Abstract

Profibus, CAN bus are two kinds of industrial field bus, which account for 30% in the field of industrial control. At present fieldbus conversion products in the market only achieves the conversion between RS232 and RS485, which can no longer meet the needs of users. However, by comparing the OSI reference model Profibus, CAN communication model structure are found to be streamlined by the OSI model, and they are only three layers, which makes it possible to interconnect with each other. Aiming at solve the problem mentioned above that the two kinds buses cannot be interconnected, Profibus and CAN bus protocol conversion interface has been designed to achieve Profibus and CAN bus protocol conversion. As the limits of microcontroller frequency, it is difficult to achieve two kinds of bus communication speed requirements. Therefore, a microcontroller + protocol chip designing method is proposed: protocol communication speed of microcontroller is low; microcontroller chip can make up for this shortcoming, which effectively alleviate the pressure on the microcontroller. When designing Profibus and CAN bus protocol conversion interface, using microcontroller AT89C52, protocol chips were selected by Siemens SPC3 and Philips SJA1000, and accompanied by a detailed software developing plan.