It’s been amazing to watch Ethernet’s rapid adoption as a widely used communication platform for industrial systems communication. I recall having numerous conversations less than 10 years ago with engineers who were completely dismissive of Ethernet–considering it an IT communications tool and not something that could withstand the requirements of industrial service. Ethernet has now become so well accepted for automation and control use that the discussion has moved beyond functionality and in to price.
A prime example of this can be seen in B&R’s recent announcement that hardware prices for PowerLink slave interfaces can be up to 45 percent lower than those for other industrial Ethernet systems with performance characteristics similar to PowerLink. According to B&R, excluding the hardware components required for interfaces in all Ethernet systems, such as plugs, transformers, and PHY, processor-based PowerLink solutions can be implemented for about $6.
B&R claims that PowerLink interface prices are lower because the technology uses the single telegram procedure and is patent free. According to B&R: “Proprietary real-time Ethernet buses employ the sum frame procedure, which means that only one large data package is sent to all network devices per cycle. This requires more complex hardware than the standard Ethernet procedure employed by PowerLink, which uses single telegrams for communicating with individual nodes.”
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In a related note, the Ethernet PowerLink group recently announced the openSAFETY protocol, which it believes to be the foundation for the first “completely open, safety-related data communication protocol for all areas of automation.” As a bus-independent protocol, openSAFETY can be used with all fieldbus systems or industrial Ethernet systems. For more information, see the related Design News article at http://www.designnews.com/article/509856-New_OpenSAFETY_Protocol.php.