Data transfer via tunneling

Using one network to transfer data from another.


Dear Control Engineering: Is it possible to transport data from a different type of network over Ethernet? For example, can we send data from fieldbus segments?

There is a technique called tunneling that sends information from one kind of network over another and converts it back at the other end. For a more thorough explanation, here are some thoughts from Corey McAtee, technical marketing manager for Beckhoff Automation. (He cites options available using Beckhoff equipment and software, but similar functionality can be accomplished with other platforms.)

EtherCAT permits IP-based protocol communication through the network using a “tunneling” concept. Examples of this include communications to remote HMI panels via Web thin client, or to a standard printer or other TCP/UDP-based components. Beckhoff calls this tunneling functionality EoE, or Ethernet over EtherCAT. With our hardware, this is accomplished using the EL6601 or EL6614 Ethernet switch port terminals which provide standard RJ45 connector(s) in order to connect network-based devices to EtherCAT. On the Beckhoff software side, TwinCAT I/O (EtherCAT master) hands these packets up to the OS layer (Windows) where they are processed like any other standard network packet.

Tunneling is not unlike the layering of protocols that is a key feature already implemented in Internet technologies used in Ethernet, such as layering TCP under IP (TCP/IP) or HTTP under TCP under IP, which is all part of our everyday computer use. By tunneling the non-time critical Internet protocols for these devices inside the EtherCAT frames, the EtherCAT network can ensure that its highly deterministic, high scan rate frames are unaffected by the communication of these comparatively slow IP-based devices.

In addition to IP-based protocol tunneling, Beckhoff has also implemented MDP (modular device profile) into our fieldbus design, providing a standard way to pass data from legacy fieldbuses over EtherCAT. As a result, Beckhoff users can implement fieldbus gateways like the EL6752 DeviceNet master terminal on the network. We treat all DeviceNet data as standard process data on the EtherCAT master side, and the terminal simply provides a translation to and from the DeviceNet network. Benefits of an implementation like this are:
1. The secondary fieldbus data is transported synchronously across the fieldbus and is not managed on the service channel; and
2. It results in reduced CPU use on the EtherCAT master due to the removal of the traditional cyclic object mapping.

EtherCAT gateway terminals are also available for Profibus, Profinet, CANopen, and more, providing exceptional flexibility in establishing communication from an EtherCAT-enabled system to non-EtherCAT devices and to older plant equipment.

No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2013 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
A cool solution: Collaboration, chemistry leads to foundry coat product development; See the 2015 Product of the Year Finalists
Raising the standard: What's new with NFPA 70E; A global view of manufacturing; Maintenance data; Fit bearings properly
Sister act: Building on their father's legacy, a new generation moves Bales Metal Surface Solutions forward; Meet the 2015 Engineering Leaders Under 40
Cyber security cost-efficient for industrial control systems; Extracting full value from operational data; Managing cyber security risks
Drilling for Big Data: Managing the flow of information; Big data drilldown series: Challenge and opportunity; OT to IT: Creating a circle of improvement; Industry loses best workers, again
Pipeline vulnerabilities? Securing hydrocarbon transit; Predictive analytics hit the mainstream; Dirty pipelines decrease flow, production—pig your line; Ensuring pipeline physical and cyber security
Upgrading secondary control systems; Keeping enclosures conditioned; Diagnostics increase equipment uptime; Mechatronics simplifies machine design
Designing positive-energy buildings; Ensuring power quality; Complying with NFPA 110; Minimizing arc flash hazards
Building high availability into industrial computers; Of key metrics and myth busting; The truth about five common VFD myths

Annual Salary Survey

After almost a decade of uncertainty, the confidence of plant floor managers is soaring. Even with a number of challenges and while implementing new technologies, there is a renewed sense of optimism among plant managers about their business and their future.

The respondents to the 2014 Plant Engineering Salary Survey come from throughout the U.S. and serve a variety of industries, but they are uniform in their optimism about manufacturing. This year’s survey found 79% consider manufacturing a secure career. That’s up from 75% in 2013 and significantly higher than the 63% figure when Plant Engineering first started asking that question a decade ago.

Read more: 2014 Salary Survey: Confidence rises amid the challenges

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.