Bp 68 en
Profibus FDL layer for Linux
Author: Tran Duy Khanh
PBMaster is a solution to connect common personal computer to Profibus, the most popular fieldbus used in factory automation. There are many solutions with hardware support from commercial companies. However the implementations of their hardware and software are usually well protected and not readily available. PBMaster doesn`t want to compete with them, but aims to offer a cheap solution with open code.
Hardware is based on cooperation between personal computer and convertor of RS-232 to RS-485, the standard commonly used by Profibus. It is possible in two ways. Using expansion cards with integrated UART chips or a simple convertor of standard RS-232 used by personal computers. The first one is more expensive, but it is able to achieve higher speeds of communication. The latter is very simple and cheap, but its highest attainable speed is only 19 200 baud.
Software is based on device driver implementing functions of master station of Profibus. The driver has been developed for Linux, but in the future I would like to port this driver to other free operating systems such as RTLinux and FreeBSD.