As with other computerized applications, industrial control and automation rely increasingly on computerized networks. General-purpose networking or connectivity solutions such as plain Ethernet or Token Ring are, however, ill-adapted to the harsh and demanding environment of industrial applications. Common Ethernet, for instance, is too vulnerable to EMI (Electromagnetic Interference) and RFI (Radio Frequency Interference) to be used in most industrial environments.
Therefore, quite a few specialized, industrial-grade networking solutions have been developed over time. In addition to being more adapted to industrial environments, these industrial networks, commonly known as fieldbuses, contribute to reducing wiring, increasing modularity, providing diagnostics capabilities, enabling self-configuration, and facilitating the setup of enterprise-wide information systems.
In the following sections, I will cover the industrial networks supported by Linux and briefly discuss the other industrial networks that have little or no Linux support. If you are new to fieldbuses, you may want to take a look at Rob Hulsebos' Fieldbus Pages located at http://ourworld-top.cs.com/rahulsebos/. The web site includes a large collection of links and references to all sorts of fieldbus systems.
The Controller Area Network (CAN) is not only the most common fieldbus, but probably one of the most pervasive forms of networking ever used. CAN was introduced in 1986 by ...