Fieldbuses have become an integrated component of automation technology. They have been tried and tested and are now widely established. It was fieldbus technology that enabled the wide-scale application of PC-based control systems. While the performance of
controller CPUs – particularly for IPCs – is increasing rapidly, conventional fieldbus systems tend to represent “bottlenecks” that limit the performance control systems can achieve. An additional factor is the layered control architecture consisting of several subordinate
(usually cyclic) systems: the actual control task, the fieldbus system and perhaps local expansion buses within the I/O system or simply the local firmware cycle in the peripheral device. Response times are typically 3-5 times higher than the controller cycle time – an unsatisfactory solution.