The interbus with transmission rates of up to 2 Mbps is characterised by especially high transmission security and a short, constant cycle time. It is divided into subsystems and consists of the remote bus, the installation remote bus and the local bus arranged in a ring topology.
As the names already suggest, the remote bus serves to connect up to 254 subscribers which are located at large distances from each other.On the other hand, the local bus connects subscribers that are located close to each other to the system.
The PROFIBUS is used in manufacturing engineering and automation. It has an unlimited number of subscribers and data transmission rates between 9.6 kbps and 500 kbps. It has a hierarchical structure with the sensors/actuators levels, field levels and the process level. In master-slave operation, the token passing access procedure is used. Here, slaves may only access the profibus upon the master’s request.
In addition to the two examples cited here, there are other fieldbus variants as well as fieldbuses on an Ethernet basis such as EtherNet/IPor EtherCAT.
Fieldbus: A Good Example of Communication in Action
In the case of fieldbus, the communication functions in terms of technology as well as in terms of cooperation with the involved partners. However, this was completely different when the fieldbus was first developed.
Now that all parties (manufacturers, organizations, consumers) have exchanged ideas with regard to the different requirements and expectations, today there are even national and international standardizations and normalizations, as well as periodic examinations in test laboratories.