Combine old and new wireless industrial networks

Application update: Existing and emerging industrial standards can be used effectively for rugged industrial applications and other hostile environments. Volcano Eyjafjallajokull exploded, but the wireless monitoring network there survived. For extreme wireless performance, watch for IEEE 802.11ad, WiGig wireless, with 60 GHz, 7 Gbit/sec capabilities.


Figure 1: In December 2009, seismographs at Iceland’s Eyjafjallajökull volcano started to report a steady increase in seismic activity. Remote GPS units observed spatial displacement. Flow meters and thermometers in the adjacent river recorded a rise in wIt’s possible to extend existing wireless networks and integrate new technologies and network topologies to improve performance in highly rugged environments. A new published standard, IEEE 802.11ad or "WiGig," seems likely to make a new tri-band Wi-Fi option available soon. Using 60 GHz, the new standard would provide a theoretical maximum throughput of up to 7 Gbit/s. At 7 Gbit/s you could record everything your factory or plant or volcano was doing while simultaneously watching it all live in 1080-pixel HDTV.

In December 2009, seismographs at Iceland’s Eyjafjallajokull volcano (Figure 1) started to report a steady increase in seismic activity. Remote GPS units observed that the local landscape was being displaced in a southward direction. Flow meters and thermometers in the adjacent river recorded a rise in water level and water temperature. By March, a small eruption had started and fissures, lava flows, and flash floods were making ground travel in the region increasingly hazardous. By mid-April the eruption had grown so powerful that the volcano’s ash cloud was shutting down air travel as well, and passengers and cargo were stranded all over Western Europe for nearly a week. Yet, through it all, the staff members at the Icelandic Meteorological Office were able to continue collecting and analyzing data from their remote devices. How did they do it?

New network topology

Industrial networks started out as hardwired serial systems. They got the job done, but they had ranges that could be measured in thousands of meters. Safely monitoring a live volcano requires rather more range than that. And hardwired connections would be problematic in a volcanic environment anyway, thanks to the seismic activity, the lava flows, and the flash floods.

Figure 2: The Icelandic Meteorological Office wireless network with remote cellular modems network-enabled various sensors via Ethernet, USB, or serial connections and then transmitted the data via the cellular telephone network. Solar panels powered theSo the Icelandic Meteorological Office went wireless. Its workers installed remote cellular modems that network-enabled their various sensors via Ethernet, USB, or serial connections and then transmitted the data via the cellular telephone network. Solar panels powered the various pieces of equipment and backup batteries (Figure 2), so there was no need to rely upon vulnerable power lines. Eyjafjallajökull eventually exploded, but the network survived.

Mixing old, new networks

Note that there was no need to purchase special sensors. Whether the remote devices were old or new, and whether they needed to communicate via Modbus or TCP/IP, the cellular router was happy to accommodate them. Thanks to media conversion, virtually any data stream from virtually any device can now be integrated into a modern network and transported via the newer media and protocols. It’s not only possible to extend the network edge to include a volcano; it’s possible to create network topologies that span the entire globe.

Until recently, cellular networks couldn’t serve as a wire replacement in every application. 3G systems could provide for data rates of several Mbit/s, which was very useful. But the specifications for the newer 4G LTE standards call for peak data rates of up to 100 Mbit/s for high mobility devices and up to 1 Gbit/s for low mobility devices. And perhaps even more intriguing, message latency, which can run in the hundreds of milliseconds for 3G, improves to tens of milliseconds over LTE. With throughput like that, the 4G LTE cellular networks will be able to serve as a true replacement for long-range cabling. The cellular providers are winding down 2G services to make room for an expected explosion in 4G LTE data networking.

Improvements in Wi-Fi

Cellular networking requires the purchase of a data plan. So for local wireless connections it’s often more cost effective to deploy Wi-Fi. But, until recently, Wi-Fi’s potential was limited by issues like multipath propagation. As radio waves tend to be absorbed or reflected by everything that stands in their way, from trees to parked cars, the transmitted signals arrive at the receiver at different times and out of sequence. The higher the radio frequency, the worse it gets.

Lower frequencies, on the other hand, provide less bandwidth and require larger antennas and more power to produce useful gain.

The IEEE 802.11n Wi-Fi standard addresses these issues. Its multiple-input multiple-output (MIMO) technology deploys multiple antennas at both the transmitting and receiving sides of the wireless connection and splits the data into numerous spatial streams. The streams are transmitted through separate antennas and collected by corresponding antennas in the receiving devices, where onboard software uses signal processing algorithms to correct and interpret the incoming data. When handled in this fashion, multipath propagation becomes an advantage instead of a problem.

MIMO 802.11n devices also employ precoding and postcoding techniques like spatial beamforming to help them communicate with one another. Spatial beamforming modifies the phase and relative amplitude of the signal to create a pattern of constructive and destructive interference in the wavefront, which simplifies interpretation on the receiving side. The 802.11n standard also adds frame aggregation to the MAC layer, and makes it possible to specify management information less frequently by grouping several data frames into a single, larger frame. As the ratio of payload data to total data volume is higher, throughput is improved. The 802.11n standard also adds 40 MHz channels to the physical layer (PHY). That’s twice the bandwidth that was available under the older 20 MHz standard.

With its multiple radios and multiple antennas, a MIMO device would theoretically need more power than a device with a single radio and antenna. So MIMO devices transmit their data in bursts and render themselves inactive during idle periods, greatly reducing the need for power.

The result of all this is that Wi-Fi’s range and reliability have seen dramatic improvements. When combined with cellular networking for long-range backhaul, an entire network topology can now be wireless.

Wireless network security

When a network includes shared or public connections like the cellular system, users don’t have the same end-to-end control that comes with a privately owned and managed system. One solution is virtual private network (VPN) tunneling. Users at a VPN tunnel’s endpoints must authenticate before the tunnels can be established, and the data is encrypted before it is sent. That gives users the same functionality and security that they’d get from a private network.

And this is only the beginning. A new published standard, IEEE 802.11ad or "WiGig," could make a new tri-band Wi-Fi option available quite soon. Using 60 GHz, the new standard would provide a theoretical maximum throughput of up to 7 Gbit/s. At 7 Gbit/s you could record everything a plant, factory, or volcano was doing while simultaneously watching the whole show live, in glorious 1080p HDTV.

- Mike Fahrion, the director of product management at B&B Electronics, specializes in data communications with 20 years of design and application experience. He oversees development of the company’s rugged M2M connectivity solutions for wireless and wired networks based on serial, Ethernet, wireless, and USB communication technologies. Fahrion has expertise in reliable connectivity solutions for devices deployed at the “edge” of networks in remote, harsh, or uncontrolled environments. Fahrion is a speaker and author who writes a self-described politically incorrect newsletter, “eConnections,” with more than 50,000 monthly subscribers. Fahrion holds a BSEE from Iowa State University. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering, mhoske(at)


See links at bottom for other Fahrion articles about industrial networks.

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...
The true cost of lubrication: Three keys to consider when evaluating oils; Plant Engineering Lubrication Guide; 11 ways to protect bearing assets; Is lubrication part of your KPIs?
Contract maintenance: 5 ways to keep things humming while keeping an eye on costs; Pneumatic systems; Energy monitoring; The sixth 'S' is safety
Transport your data: Supply chain information critical to operational excellence; High-voltage faults; Portable cooling; Safety automation isn't automatic
Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Plant Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.

Maintaining low data center PUE; Using eco mode in UPS systems; Commissioning electrical and power systems; Exploring dc power distribution alternatives
Synchronizing industrial Ethernet networks; Selecting protocol conversion gateways; Integrating HMIs with PLCs and PACs
Why manufacturers need to see energy in a different light: Current approaches to energy management yield quick savings, but leave plant managers searching for ways of improving on those early gains.

Annual Salary Survey

Participate in the 2013 Salary Survey

In a year when manufacturing continued to lead the economic rebound, it makes sense that plant manager bonuses rebounded. Plant Engineering’s annual Salary Survey shows both wages and bonuses rose in 2012 after a retreat the year before.

Average salary across all job titles for plant floor management rose 3.5% to $95,446, and bonus compensation jumped to $15,162, a 4.2% increase from the 2010 level and double the 2011 total, which showed a sharp drop in bonus.

2012 Salary Survey Analysis

2012 Salary Survey Results

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.