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Powering IIoT – via Ethernet

Sept. 9, 2015
Most sensors require more consistent power than batteries, solar or wireless sources can provide. One possible solution is PoE, which Emerson says enables wireless connection without extra wired power infrastructure. 
The potential to create ubiquitous measurement and control, which is a central element in the Industrial Internet of Things (IIoT), is all well and good but, as those in the real world know, there are sometimes practical barriers to achieving that goal.

One of those barriers is power, given that most devices still require more power and more consistent power than batteries, solar or wireless sources can provide.  And traditional hardwiring for AC is expensive!  Fortunately, there is a promising option in the form of Power over Ethernet (PoE) – a term that actually describes multiple techniques for using existing Ethernet wiring to provide substantial (at least from a sensor standpoint) power. So, where Ethernet currently exists or could easily be extended, there is a robust and familiar option for powering up IIoT technologies.

Emerson Process Management, for one, has added PoE to its Smart Wireless Gateway 1420, making it possible to power the gateway and compatible devices using a standard Ethernet cable. According to the company, the inclusion of PoE allows easy, economical installation of wireless Gateways without requiring extra power wiring infrastructure.

In addition to providing infrastructure flexibility in places where there is limited access to power, by using an Ethernet cable connection, a new PoE Gateway can be easily installed and powered by an existing wireless access point. Alternately, PoE allows the Gateway to power any Ethernet-enabled instrument.

PoE has a number of strengths. For one thing, it allows long cable lengths, especially compared to USB. Power may be carried on the same conductors as the data, or it may be carried on dedicated conductors in the same cable.  Wiring also generally involves less complexity than would dedicated AC lines.

Because there are so many different ways of implementing PoE, it can be adapted to the needs of different equipment or situations. IEEE has blessed some of these methods (see IEEE 802.3af), but there are many others flourishing in the wild.

Of course, the lack of a single standard PoE protocol means it’s not always a simple matter of “plug and play,” still PoE offers a forgiving and adaptable tool for taking important steps toward IIoT implementation.

Incidentally, Peter Zornio Chief Strategic Officer, Emerson Process Management, will be speaking about IIoT at our Smart Industry 2015 conference, Oct. 5-7, in Chicago. His topic is “A Revolution Decades in the Making: IIoT in the Process Industries.” Zornio sees many useful lessons for IIoT implementers from the experience of the manufacturing industries to date in deriving business value from existing IT technologies. In particular, his talk with include some of the lessons learned about dealing with barriers like complexity, security, information reliability and risk aversion.

PoE is, of course, one of those tried and true technologies that pioneers have been leveraging for some time. And it is one that will probably help IIoT become a reality.

Alan R. Earls is a Boston-based writer focused on technology, business, and manufacturing — a field where he spent the earliest part of his career. He has written for publications and websites as diverse as The Boston GlobeComputerworld and Modern Infrastructure as well as Industry, The Manufacturer, and Today's Machining World.