Choose Your Favorite Flavor of Ethernet to the I/O

Many Flavors of Ethernet

Talking about using Ethernet on the factory floor or in the canyons of metal that constitute a process plant was almost revolutionary when we first covered it in the Industrial Automation Review in February 2005.

While we can't say that this ubiquitous networking technology can be found everywhere in manufacturing, it is no longer surprising to hear of an engineer seriously considering it for the next project—or even for a retrofit.

When our series Editor Terry Costlow went out for research for this piece, the surprising element was all the varieties of Ethernet that he found. While some companies prefer to use “standard” Ethernet, meaning the common protocol stacks and physical layer used in business and home networks. Others have tweaked the stack in one way or another in order to optimize it for a particular set of applications, or perhaps to gain a competitive advantage rather than use a network favored by a rival.

These differences lead to a variety of arguments about who is truer to the standard, or whose network requires “proprietary” hardware or firmware. These debates may be entertaining to editors, but they can be downright confusing to engineers trying to figure out the best way to implement a new project. Read more

Ethernet's Not the Only Game in Town - There’s more need for tools, but they must measure up.

Ethernet continues to expand its role in the factory, but it's facing some stiff competitors as it stretches down to the input/output (I/O) level. When engineers need to connect sensors and other simple components, they've got a number of alternatives that are often more cost-effective than Ethernet.

A range of architectures provide the low cost and performance needed for I/O connections. At the same time, wireless technologies are addressing ease of use, eliminating the difficulty of routing wires every time equipment is moved or new gear is added. Though skeptics scorn the reliability of sending signals through the air of a noisy factory, there's little doubt that wireless is going to play a solid role in the factory of the future.

Ethernet will also hold a significant role in data gathering. It's dominating as a central network when production facilities are upgraded, bringing compatibility with the front office. A number of companies are now eyeing the large number of I/O nodes that fill today's factories, hoping to displace the fieldbuses often used to link these nodes to Ethernet or other factory-wide backbones. Speed is a key weapon in their arsenals.

“We're betting the farm that Ethernet to remote I/O is the way to go. With today's switched networks, speed is not an issue. It takes less than a millisecond to send a message,” says Tom Edwards, senior technical advisor at Opto 22, a Temecula, Calif.-based vendor

Pick Your Flavor

Other companies and technology groups are promoting various flavors of Ethernet, using different approaches to keep performance high without pushing costs up. For example, the EtherCat architecture keeps costs down by using an application-specific integrated circuit, or ASIC, to handle network communications, making it possible to use less powerful, less expensive central processing units (CPUs) in equipment. “Our ASICs or FPGA (field programmable gate array) implementations are typically cheaper than what competitors use for the underlying fieldbus applications,” argues Joey Stubbs, North American representative for the EtherCat Technology Group, based in Nuremberg, Germany... Read more

Software Tools Manage Data Flow - As communication technologies move toward seamless integration for an enterprise, automating data gathering and data movement is coming into the spotlight.

Humans don't want to think about the data being gathered until it suits their schedule, or when problems require immediate attention.

ILS Technology is one of the companies tackling this challenge, providing software that helps automate the data flow. Its DeviceWise tools make it simple to set up reporting structures and quickly set or change the data that's gathered from various nodes.

“Without programming, people can select the payloads they want to send upstairs, for example. You can pick things like the high, low or average of 50 variables you want to monitor every 10 minutes and send that data up to the enterprise,” says Fred Yentz, chief operating officer at ILS, of Boca Raton, Fla.

Much of the benefit comes from transferring data from equipment on the plant floor up to the front-office systems. However, data flows both ways. “It isn't just data collection that's uploaded. We can receive instructions from the enterprise side and do something downstream,” says John Keever, chief technology officer at ILS

Much of the benefit comes from transferring data from equipment on the plant floor up to the front-office systems. However, data flows both ways. “It isn't just data collection that's uploaded. We can receive instructions from the enterprise side and do something downstream,” says John Keever, chief technology officer at ILS.

When companies want to print serial numbers or other changing data, the software gathers the necessary information from the host, then manages it until the job is finished. “If you're printing at very high speeds, we can load a very specific set of print codes and validate each batch, then go to the enterprise and get another batch,” Yentz says. A big benefit is that these actions can take place even if the network connection is lost. That eliminates the waste that can occur when network connections are lost at about the time jobs should end... Read more

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