For the most part, higher demands are placed on communication in the field than those in office communication. Real-time capability and deterministic behavior are of utmost importance in this respect. Jitter behavior in the micro second range and extremely high resistance to disturbance are important factors.

ETHERNET Powerlink provides a standard protocol for Fast Ethernet, which has proven its tough real-time characteristics in thousands of applications. The ETHERNET Powerlink Standardization Group (EPSG) ensures openness and continuous advancement. Powerlink as Standard Ethernet based system represents the second generation of fieldbus. This makes it possible to apply the full power of IT technologies to the automation field for the first time. ETHERNET Powerlink is comparably suited for drives, I/Os, visualization and data exchange between PLC systems.

CAN bus has had much success, particularly in machine manufacturing, and is steadily gaining importance. High resistance to disturbance, high-speed data transfer, ease of use and deterministic real-time behavior are among the reasons for this success. CAN is the ideal fieldbus for applications with a manageable number of remote I/O nodes and few axes.

As a fieldbus, CAN bus reaches its limits when dealing with larger and more complex machines. For these applications however, ETHERNET Powerlink is the ideal expansion in the higher performance range.

Decentralization is the dominating trend in automation technology. This has come about as a result of economic considerations and the total cost reduction of machines, by those who see the clear advantages of a decentralized structure for multiple applications. These demands brought about the idea of running the conventional backplane for the I/O modules in a PLC system or a bus controller in one cable. The result is the extremely high-speed I/O connection, X2X Link.

Now, just as ever, interfaces such as RS232, RS422 and RS485 play an important role in the automation world. Robust, simple and nevertheless efficient, these interfaces still find wide usage. The classic RS232 interface is fully capable of meeting the demands for system programming and maintenance.