Fieldbus and FCS

Shortly after the appearance of soft PLC, a new wave of technology rushed into the industrial control market, which is Fieldbus. At the same time, the concept of FCS was derived from Fieldbus. At the beginning, I was also an advocate and developer of FCS, and I was convinced that FCS is the future control system today with increasingly strong chip capabilities and lower prices. However, in the actual development and application process, we found that after full decentralization, not only the cost increased, but also the maintenance became more difficult, because all nodes depended on the network, and the reliability of the network became a bottleneck. Any short circuit or open circuit in such a long network cable will cause fatal damage. If redundant networks and systems are used, the cost will increase greatly. Moreover, the distributed logic will lead to a major error of the whole system because of the failure of an intermediate node. Of course, if the user has a deep understanding of the distributed control concept, there is no big problem, but in fact, it is unrealistic for the user engineer to understand such a complex topological structure and consider such a complex field structure.

Unless there is new development in the research and development of neural network chips in the future, one logical operation node can be automatically replaced by another logical node when it is damaged. At the same time, better network-based logic programming software is needed, which can reasonably divide the distributed controllers and deal with the situation after any node is damaged in a reasonable way, or protect or ignore it. The ideal development of FCS is that there are only sensors and actuators without a separate controller. All sensors transmit their own parameters to the required actuators, and each actuator operates and controls according to the parameters obtained by the network, and at the same time transmits the intermediate values obtained by its own operation to other actuators. Because of the problem of intermediate value, the whole control network will become quite complicated, and every point with intermediate value must have a reasonable treatment strategy. Ideally, when there is a problem with the intermediate logic point, it can be replaced by any logic point or a reasonable protection strategy can be carried out. In the foreseeable time, we will see a brand-new FCS that can meet all the requirements, and it will become more flexible and reliable in communication.