03 October 2001
Cost-saving “enablers” speed networking
Industrial Ethernet, Internet/intranets and custom chips spur manufacturers
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 makinga 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 thatthey 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.
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 on-site 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 real-time 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 nondeterministic are the statistical setbacks after a collision. Take away the collisions, and the result is determinism.”
Not for Critical ControlYet
For critical, potentially hazardous control applications, “a number of steps need to be taken” before Ethernet can be used, however, acknowledged Hietanen. Ethernet has “hooks and handles” for critical control applications, he said, but “it’s not quite there yet in terms of backup.” For example, “if PLC A is talking to a device and it switches to PLC B, the system has to know that [very rapidly], and Ethernet isn’t there yet.”
Internet/intranet-based control, while a popular discussion topic at manufacturing-related technical conferences, remains in the infancy stage, the GE Fanuc executive said. However, low-cost connections are spurring numerous Web-based networks that business decision makers can use, for example, to monitor plant-floor inventories and production operations.
On the software side, Javaand its Jini sister language, designed for smaller, device-level connectionsis also an enabling technology for expanding industrial communications networks.
In a technical paper written for September’s ISA 2001 Conference & Exposition in Houston, Michael R. Tennefoss, vice president of product marketing and customer services for LonWorks developer Echelon Corp., contended: “The reality is that adding [industrial] Ethernet connectivity to every sensor and actuator is expensive, difficult to manage, and not sufficiently robust for many applications.”
Tennefoss proposes a hybrid system that combines a distributed control infrastructure based on the ANSI 709.1 protocol, together with Ethernet networks running IP. ANSI 709 combined with TCP/IP would, he said, “provide an open, end-to-end, interoperable infrastructure for networking control devices over a wide variety of media, using robust physical layers, a comprehensive network management scheme, and meeting industrial [electromagnetic compatibility (ESD)] and environmental specifications.”
Echelon contended manufacturers can cut costs and quickly get products to market by using neuron chips, a family of microcontrollers that drive millions of LonWorks devices currently deployed. Neuron chips are manufactured and distributed worldwide by Echelon semiconductor partners Cypress Semiconductor and Toshiba Corp.
The LonWorks-friendly ANSI 709.1 standard is an intelligent, distributed networking infrastructure that allows devices to communicate directly with one another on a peer-to-peer basis, without needing a PLC or central controller. Each device is locally intelligent and communicates on a shared communication medium with any other device on the network.
Tennefoss said ANSI 709.1–compliant nodes are widely used for pump and valve control, robotics, mass flow control, vacuum deposition, clean room air handlers/scrubbers, gas delivery and monitoring systems, welding, paint and adhesive application, measurement and instrumentation, SCADA systems, and related industrial applications.
“Ethernet’s original intended use—corporate data networks—represents relatively benign electrical environments,” the Echelon executive said. “Burst noise, electrical surges, radiated noise, magnetic fields, and so on manifest themselves at fairly low levels. Contrast this with a typical factory floor, which is a virtual firestorm of electrical activity. Making an industrial Ethernet network work in such an environment requires the addition of surge suppressors, ESD protection devices, and a host of other protective mechanisms that ANSI 709.2 and ANSI 709.3 simply do not require,” he argued.
At last month’s ISA 2001 Conference & Exposition, Ci Technologies unveiled a relatively low-cost (about $4,000) suite of Ethernet-based software products designed to transfer plant and industrial process data throughout entire business organizations.
Called Plant2Business, the software is also compatible with human-machine interface/supervisory control and data acquisition products from Citect competitors Intellution and Wonderware, Volckmar said.
The Ci Technologies executive said he believes Plant2Business is the first commercial off-the-shelf product a manufacturing company’s business decision makers can use to access plant floor data from anywhere in the business organization over the Internet.
Looking ahead, advances in semiconductor technologies could ultimately enable billions of electronic devices to invisibly collaborate with one another, as well as with human controllers.
However, embedded Internet/Ethernet connectivity is still difficult to engineer. And for embedded Internet/Ethernet to permeate the device world, connectivity must be as simple as plugging into a wall jackwithout any hardware or software configuring.
As the cost of networked system-on-a-chip components drops, embedded connectivity will begin to be as universal as embedded microcontrollers are now, said NETsilicon’s Peterson. Blazing the trail will be business and industrial applications where the value of the connection outweighs the cost. As that volume grows, costs for other applications will continue to drop.
This major evolutionary step in embedded systems technology is already under way, as virtually all newly designed “smart” systems and devices include connectivity, Peterson said. Intelligent embedded systems are no longer islands unto themselves; they are interconnectedand he envisions the effects of this transformation are going to be dramatic. IC
Figures and Graphics
Jim Strothman is an associate editor for InTech.
Return to Previous Page