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Japan`s 1Gb/s Ethernet network is `ten times faster`

11 November, 2007

Japan is mounting its first serious challenge to the dominance of Profibus- and DeviceNet-based Ethernet networking technologies in Europe and North America, with the announcement of a new, open 1Gb/s technology that uses fibre optic connections. The CC-Link IE (Control and Communication Link Industrial Ethernet) system is claimed to be ten times faster than its rivals, and quick enough to cater for almost any real-time communications requirements.

Until now, interest in CC-Link has been limited largely to the Asian market, where its backers claim it is the leading industrial network. Users in the West have mainly been subsidiaries of Asian companies, or Western OEMs exporting to the Far East.

CC Link IE model

But CC-Link’s champions believe that the new high-speed Ethernet version could help it to make the breakthrough into the European and North American markets, especially for demanding applications. There will eventually be a hierachical family of networks including field-level, motion control and safety versions (as shown above).

CC-Link started life as a proprietary fieldbus, developed in-house by Mitsubishi Electric in 1996. Three years later, the company made the protocol open, "in response to customer requests". Since 2000, the technology has been supported and guided by the CC-Link Partner Association, which expects to have more than 1,000 members by the end of this year – 57% of them outside Japan.

There are now around 900 products compatible with the earlier versions of CC-Link, including the recent safety and sensor/actuator versions. By the end of this year, it is estimated that there will be more than 5.3 million CC-Link nodes installed around the world.

As well as its high speed, the new Industrial Ethernet version is claimed to offer other attractions. For example, it uses a dual-loop, redundant architecture to ensure that communication continues, even if a cable is broken or a station is lost. Data can be sent in either direction through a loop, allowing the system to "self heal" itself around a problem.

A shared, distributed memory system allows any controller in the network to "know" what is happening elsewhere in the network. Data flows are controlled by "tokens" which controllers pass from one to another.

The frequency of the cyclical communications is independent of the load and is thus constant, predictable and deterministic. According to the CLPA, data updates do not slow down when the network traffic is heavy.

Individual CC-Link IE networks can support 120 stations, spaced up to 550m apart, and 239 of these networks can be linked together, potentially creating massive systems extending more than 14,000km and containing more than 25,000 nodes.

Although the fibre connections are likely to be more expensive than copper wiring, the CC Link developers argue that the extra cost is justified by the higher performance, longer range, lighter weight and immunity from interference that fibres provide.

The first products supporting CC-Link IE are due to reach the market in the first quarter of 2008. The developers have drawn up a roadmap that includes the field-level and motion control versions, both scheduled for 2008, and the safety version targeted for 2009.

As part of the drive to raise the profile of CC-Link in Europe, CLPA recently appointed Mitsubishi’s former UK divisional manager, Steve Jones, to be general manager of the CLPA’s European activities. Jones says that discussions are underway about setting up a CC-Link conformance testing centre in Europe, which he believes is "essential to be taken as a serious contender".

He describes the move from copper to fibre communications as "a brave choice", but predicts that "in two to five years’ time, we will be asking why we didn’t do it before".




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