Reducing material consumption requires close attention to every detail, precisely monitoring every sensor and actuator with a speedy network. Manufacturers can see significant benefits by using faster networks.

“The pressure curve was very wavy with the old system,” says Chris Choi, chief technology officer for plastics machine vendor Husky Injection Molding Systems Ltd., of Bolton, Ontario, Canada. “With faster sampling time, pressure tracking becomes much closer to ideal. That lets us control the melting point more precisely, which results in much thinner walls.”

The mainstay in shortening those sampling times is a faster device-level network. Husky is one of a growing number of companies that’s using Ethernet as its only network. Though some vendors argue that existing fieldbuses are better suited for input/output (I/O) device level communications, engineers such as Choi feel that the benefits of Ethernet far outweigh the downsides. “Profibus and proprietary connections are slower,” he says. “With Ethernet, we don’t have any latency, so the whole system goes faster.”

That speed is the key to letting its customers save money and reduce waste with thinner walls, he explains. In a volume production run of 55 million parts per year, trimming just two grams from a 22-gram package can save $180,000. To make that happen, Husky employs one of the real-time Ethernet technologies, EtherCat, throughout the system. However, Choi muses that customers couldn’t care less what architecture the equipment uses so long as they can save materials, which also helps them win sales in this environmentally conscious era.

The equipment designers who help companies such as Husky do need to think about every aspect of their designs. Networks are a key element in the full systems architecture, touching on both performance and cost. Though Ethernet’s speed improvements may seem minor, they can make a big difference.

“EtherCat’s bandwidth is very important. If you’re sensing and actuating, and you get back or send signals using a faster network, you can gain 2 percent to 5 percent without changing anything else,” says Graham Harris, president of Beckhoff Automation LLC, of Burnsville, Minn. Gaining a few microseconds on activities that occur thousands of times each day adds up to significant improvements over time, he adds.

Cabling made easy

One of the reasons that industrial users are extending Ethernet down to the lower levels of their systems is to simplify cabling. Using a single medium at all levels can reduce complexity and give installers more freedom. At the same time, many consumers find this approach also saves them money.

Many Ethernet proponents say that DeviceNet, Profibus, or proprietary wiring schemes that have seen widespread use have far more rules and requirements than the Ethernet cabling that’s continuously being installed in homes and offices. Simplicity and home installations are tightly linked. “Ethernet wipes away a lot of the cabling issues that exist with legacy techniques,” Harris says. “You can string Cat5 (Category 5) cable around with a lot fewer rules of engagement.”

Those Ethernet cables are extremely simple to connect, and they’re much easier to troubleshoot than many existing schemes. That’s important, because wiring can be a time-consuming aspect of an installation. “When you have to hard-wire connections, you’ve got a lot of wires. Every connection increases time and the need for checking out the wiring,” says Mike Hannah, NetLinx Product Business Manager for supplier Rockwell Automation Inc., in Mayfield Heights, Ohio.

That simplicity was important for Husky. Lower costs were a nice side benefit. “We use the same cabling everywhere,” Choi says. “The costs can be significantly lower than with anything else.”

Though cables and connectors used in industrial applications are typically ruggedized, they still leverage the standard’s huge volumes. Ethernet cables for industrial usage can be a quarter of the prices of other cables, Harris says. Ethernet connectors can also be substantially less costly.

DeviceNet and Profibus cable/connectors and CC-Link  cabling are all quite expensive, says Ted Thayer, automation systems product manager for vendor Bosch Rexroth Corp., of Hoffman Estates, Ill. “Other accessories that may be used with these networks, such as Profibus switches and CC-Link wireless transmitters, are also very expensive.”

Expenses are trimmed because Ethernet cables can be used anywhere, eliminating the need to stock separate sets of cables and connectors for fieldbuses. Although industrial cables are noticeably different from the versions sold in retail outlets, consumer-grade cables can always be used in a pinch if an Ethernet cable breaks and there is not a similarly sized cable sitting in the technician’s toolbox.

“If a cable breaks, you can ...