Influence of Token Rotation Time in multi master PROFIBUS networks

Increased use of fieldbus technology coupled with the increased confidence of the end user have resulted in some interesting applications using multi-master PROFIBUS networks. However the procedure for calculation of token target rotation time (T_TR) for individual masters and subsequent influence on the bus cycle is not well understood or documented. This paper reports on the experimental work carried out on evaluation of the influence of T_TR in multi-master PROFIBUS networks and master behavior. It concludes that implementation of T_TR varies widely between the vendors and calls for more stringent testing and certification of master devices.