By Keith Larson, VP Content,
As part of our 20th anniversary celebration this year, Controls editors are taking a look at the continuing evolution of key technologies, with a particular eye toward where the next 20 years might bring us. Indeed, a special microsite at ControlGlobal.com/20years is home base for a growing library of video FutureCasts exploring a a range of important process autmation technologies. Im first up this month with a look at industrial networking technologythat is, the increasingly prevalent use of digital communication protocols to communicate and integrate process control and plant information streams.
First a bit of context. When the first issues of Control were published in the late 1980s, Ethernet had already begun its conquest of the enterprise networking space. Meanwhile, throughout the 1990s, the process automation industry haggled over a network standard of its own that would be compatible with the extensive installed base of 4-20mA twisted-pair copper wire used for analog process signals.
Fast forward to 2008. Ethernet and its various derivatives have conquered all but that industrial last milethat final stretch of connectivity to a given temperature transmitter or proximity sensor. At this level, as an industry, we still deploy a Dukes mixture of industry-proprietary protocols and custom silicon, including Foundation, Profibus, Devicenet, etc.
But the technical reasons for not having a single, unified network architecture from top floor to bottom are falling one by one. Security considerations notwithstanding, the day is coming when that desktop computer in the CEOs office, as well as the distant pressure transmitter atop the distillation tower, exist as TCP/IP addresses on the same Ethernet architecture. Ethernet chipsets are now cheap enough to be embedded in the lowliest devices, even as existing industrial protocols are modified to run on Ethernet-compatible physical media, even simultaneously with other protocol stacks.
The process industries, of course, have come to expect loop-powered instrumentation, but continuing advances in power-over-Ethernet standards promise to overcome even this last limitation to delivering device power over the same wire as the digital Ethernet signal. Meanwhile, lower-powered devices themselves, developed in part to support wireless instrument networks, will further accelerate this trend.
And, speaking of wireless, youd have to be living under a rock not to have heard about the process automation industrys latest efforts to remove physical media altogether from the networking equationa true return to the original Ether, so named for the ubiquitous substance once thought to support the propagation of electromagnetic waves.
Were in the early stages of wireless adoption, and at times they seem a lot like the early days of fieldbus: Committees work toward a consensus standard continues even as vendors and early adopters demonstrate the technologys game-changing potential.
So twenty years from now, what will be the networking state of the art in process manufacturing plants? Faster networks? Certainly. Increased reliance on commercial networking technologies? Undoubtedly. More wireless applications? Inevitably.
But my best bet is that 2028 will look a lot more like 2008 than one might think. For example, a just-completed survey of Control readers indicated that a full 54% of survey respondents still use mostly 4-20mA analog hardwiring for instrument communications. Only 12% reported using primarily digital buses.
So, despite all the advances in digital field communication technologies over the years, more than half of Control readers still rely on technology that matured some 40 years ago. By their very nature, disruptive advances are impossible to forecast, but from here its straightforward to extrapolate a networking future thats faster, more wireless, yetwith some much- needed help from the supplier communityincreasingly easy to set up and manage.