Multiple flavors of Ethernet

The evolution and proliferation of Ethernet has smoothed the path to integrating the automation space, enabling open protocols such as OPC to function optimally. This is part of a Control Engineering December cover story.

12/07/2010


Although Ethernet in and of itself isn’t interoperable, its evolution and proliferation has smoothed the path to integrating the automation space, enabling open protocols such as OPC to function optimally. A number of Ethernet network variations are available today, among them Ether- Net/IP and EtherCAT.

Applying a standard Ethernet technology such as EtherNet/IP lets facilities unite disparate batch, continuous process, discrete, safety, motion, and drive control industrial network technologies into a multidisciplinary industrial network. EtherNet/IP, a network technology built on the common industrial protocol, or CIP, is managed by ODVA (www.odva.org). It can coexist with an IT Ethernet network, and is described by Rockwell Automation’s Mike Hannah as an enabler. “It is more or less the piping that allows data to move from one point to another,” he added. “Because it uses the same TCP/IP protocol stack that Ethernet uses for data, no special switches or gateways are needed when data are required to move between VLANs and subnets. This means that EtherNet/IP can be more than a fieldbus network; it can be the automation network as well, simplifying the network infrastructure.”

Another Ethernet variation, EtherCAT is an open, real-time network intended for control automation technology. This fieldbus protocol was among the innovative technologies adopted by a photovoltaic and automotive supplier recently to meet communication needs. In this case, EtherCAT acts as the primary fieldbus system and a Beckhoff Automation terminal system allows integration of peripheral devices and subsystems.

“EtherCAT is able to communicate effectively with hardware in the field unencumbered by multiple software suites and works well as a gateway to other fieldbus protocols, including the associated legacy devices,” explained EtherCAT Technology Group representative Stubbs. “It can be used for motion, complex CNC machines, and robotics, with a flexible topology that allows advanced data acquisition and high-speed performance. EtherCAT uses the controller efficiently, sorting data ahead of time, eliminating the need to map data with every I/O scan. Its use of Ethernet bandwidth efficiently translates into speed. Benefits trickle down, creating a simpler system overall.”

 

- Jeanine Katzel for Control Engineering, as part of the December 2010 Cover story: Integrating Disparate Control Systems.



No comments
Consulting-Specifying Engineer's Product of the Year (POY) contest is the premier award for new products in the HVAC, fire, electrical, and...
Consulting-Specifying Engineer magazine is dedicated to encouraging and recognizing the most talented young individuals...
The MEP Giants program lists the top mechanical, electrical, plumbing, and fire protection engineering firms in the United States.
Combined heat and power; Assessing replacement of electrical systems; Energy codes and lighting; Salary Survey; Fan efficiency
Commissioning lighting control systems; 2016 Commissioning Giants; Design high-efficiency hot water systems for hospitals; Evaluating condensation and condensate
Solving HVAC challenges; Thermal comfort criteria; Liquid-immersion cooling; Specifying VRF systems; 2016 Product of the Year winners
Driving motor efficiency; Preventing Arc Flash in mission critical facilities; Integrating alternative power and existing electrical systems
Putting COPS into context; Designing medium-voltage electrical systems; Planning and designing resilient, efficient data centers; The nine steps of designing generator fuel systems
Designing generator systems; Using online commissioning tools; Selective coordination best practices
As brand protection manager for Eaton’s Electrical Sector, Tom Grace oversees counterfeit awareness...
Amara Rozgus is chief editor and content manager of Consulting-Specifier Engineer magazine.
IEEE power industry experts bring their combined experience in the electrical power industry...
Michael Heinsdorf, P.E., LEED AP, CDT is an Engineering Specification Writer at ARCOM MasterSpec.
click me