because you start from scratch with new technology, but most implementations are migrations.”

Either way Jansons recommends a phased approach, starting with installing the infrastructure. Then you phase over part of the plant, running both networks in parallel. Finally you gradually transfer the load completely from the legacy network onto the new network.

Sounds easy right? Well, like anything, there are numerous pitfalls that can trip you up.

“Too often people forget about the word ‘industrial,’” says Bryant. “The plant floor is not the back office or home and in keeping with that Industrial Ethernet is not the same IT and home networks typically are installed in controlled environments."  Industrial Ethernet requires the same ruggedization and shielding that your old field bus network required.

“The next thing people forget about is the fact that the person responsible for getting the network up and running is the automation engineer,” adds Bryant. “Because we’re talking Ethernet people think about it from an IT perspective, but at the end of the day IT isn’t always the one troubleshooting it. Considering the demanding uptime requirements of the plant-floor, there really isn’t time to call in IT every time there is a glitch or a change. So you need to think about what the automation engineer is going to need. What tools is he familiar with? Where does he want his diagnostics data?”

Siemens has specifically designed its Ethernet products with the automation engineer in mind, says Rajani. “For example, with our products you can set up devices to act like I/O devices, which makes it easier for the automation engineer. The software package you use to set up your PLCs configures your switches, which are set up as an I/O drop on the network. So whatever diagnostics you desire from your switch can come directly into the PLC. This allows existing HMI already in use to easily display this data directly to the operator.”

“It’s not really, ‘hook up the cable and it’s all good’,” adds Jansons. “Take a little bit of time, think it through and design it properly. Industrial Ethernet has a lot of advantages and you just have to give it the same due diligence you would if you were putting in something else.”

Ethernet Timeline
• 1973: Ethernet invented at Xerox PARC
• 1980: Digital Equipment Corp., Intel and Xerox release a standard for 10M bit/sec Ethernet
• 1991: 802.3 10BaseT standards is approved, for 10M Ethernet over twisted pair telephone wire
• 1995: 802.3 100Base-T 100 M Ethernet standards is approved
• 1998: 802.3ac Gigabit Ethernet standard is approved
• 1999: 802.11b standard approved, for 11M wireless Ethernet
• 2002: 802.3ae 10G Ethernet standard is approved
• 2003: 802.11g standard approved, for 54M wireless Ethernet
• 2009: 802.11n standard expected to be approved for 600M wireless Ethernet
• 2010: 100G Ethernet expected to be approved

Industrial Ethernet Resources:
• The Industrial Ethernet Advisory Group, a resource and community that covers all aspects of Industrial Ethernet, including a forum for technical support and queries, news and events, articles and product information. www.industrialethernet.org
• An explanation of Industrial Ethernet and its various components from Siemens, a major Industrial Ethernet supplier: http://tinyurl.com/ddo93u
• Industrial Ethernet, 2nd Edition, by Perry S. Marshall and John S. Rinaldi, a reference tool on installation and troubleshooting of Industrial Ethernet networks. The book is intended to help readers “prepare to plan industrial Ethernet installations with realistic expectations, make knowledgeable purchasing decisions, and identify and prevent common causes of failure.”
• Industrial Ethernet on the Plant Floor: A Planning and Installation Guide, by Robert Lounsbury, also provides guidance on how to plan an Industrial Ethernet network, including a discussion of network architectures, components, product selection and the basics of noise.