Cost-saving 'enablers' speed networking

InTech, Oct 2001 by Strothman, Jim

Although the bursting dot.com bubble washed away big chunks of the communications industry, several key enabling technologies are quietly transforming manufacturing networks worldwide.

Ethernet and companion protocols such as TCP/IP, customized chips, "black box" gateways, easy to use software languages such as Java and its sister Jini, and Internet/ intranet technologies are all easing manufacturers' network expansion headaches.

Simply stated, manufacturers need to expand networks so they can access business information more rapidly. That capability translates into faster and better decision making-a necessity to survive in today's highly competitive business environment.

Since Ethernet has long dominated the business side of the networking world, it's no surprise business decision makers also want Ethernet-friendly protocols and translation technologies to link them to inventory and process data on the factory floor.

Nevertheless, "the reality is most customers won't rip out equipment they have and start over," said Dave Hietanen, GE Fanuc's Ethernet product manager. "I agree with that-they have too much invested," said Frank Volckmar, Ci Technologies Inc. vice president of sales and marketing.

"They will replace [communication] lines, however," Hietanen said. Some legacy equipment has serial ports, some are point to point, and others are fieldbus based, the GE Fanuc executive said. "Then Ethernet shows up on the business side, and now there's Internet. Most [manufacturers] will find a way to tie that together, and the controller tends to do that" using data concentrator or gateway technologies, Hietanen said.

Network-Savvy Chips

To help Ethernet and industrial Ethernet along, third parties such as NETsilicon and Lantronix, among others, are integrating powerful, network-enabled microprocessors with an operating system, networking software, and development tools.

The goal is to have OEMs embed the chips into their electronic devices, enabling them to connect to the network via Ethernet.

Once connected, users can manage service and access products from virtually anywhere. Pete Peterson, NETsilicon CEO, said adding intelligence and network connectivity to devices via semiconductor technologies "opens up a world of new possibilities":

* Remote monitoring and diagnostics: Manufacturers can support products remotely after the sale, diagnosing problems and even downloading repair solutions. If onsite repairs are required, the technician arrives with exactly the right parts.

* Upgrades: Manufacturers can offer software upgrades that download directly to the product.

* Remote operation: A networked device can be accessed via an Internet browser. A technician can monitor status, send commands, and even get e-mail or pager alerts from the product if there is a problem. Networking suppliers and systems integrators also say they are beginning to see "black boxes" coming onto the market with Ethernet on one side and Foundation fieldbus or Profibus on the other. Others translate DeviceNet to Ethernet, they said.

EtherNet/IP Gains Support

Industrial Ethernet, known as EtherNet/IP, is an open networking protocol that uses existing commercial technology. Its components include standard IEEE 802.3 Ethernet as a base to define the cable and network services; TCP/IP; and control and information protocol (CIP), which provides realtime I/O messaging and information and peer-to-peer messaging.

Backed by the 150-member Industrial Automation Open Networking Alliance and 35-member Industrial Ethernet Association, EtherNet/IP's technology is owned and managed by the Open DeviceNet Association and ControlNet International.

Industrial Ethernet's detractors criticize it for not being deterministic, meaning it may cause a time-critical communications delay. However, GE Fanuc's Hietanen, among others, argued determinism is really in the eye of the beholder.

"Determinism is like asking, `What's real-time response?' he said. If someone is running a pump on a wastewater system and commands can come as much as 30 seconds apart, that's sufficiently "real time" for that application, he said. On the other hand, "a high-speed conveyor that needs to read a sensor every 5 milliseconds is a different story." The scan time of a typical programmable logic controller (PLC) is in the range of 20-30 milliseconds.

"Certainly full duplex on Ethernet is also helping a lot," Hietanen said. "We see no collisions on full duplex, meaning the message will get through." Collisions sometimes occur using half-duplex mode.

Former fieldbus standards leader and networking expert Richard H. Caro is even more strongly opinionated on the subject of Ethernet's determinism. "It's time everyone understood that 100BaseTX Ethernet networks with full duplex switches have no collisions and are by definition deterministic. What makes CSMA/CD Ethernet non-- deterministic are the statistical setbacks after a collision. Take away the collisions, and the result is determinism."

Not for Critical Control-Yet