Ever since the first direct digital control system was applied some half-century ago, input/output (I/O) has been essential to process automation system architecture. And for just as long, the engineering of that I/O has been complex, and the fruits of that labor rigid and inflexible.
First, take the specification of conventional rack-mounted I/O cards, each of which uses shared circuitry to deal with a specific number of similar input or output channels. Then add to that the design of associated controllers, marshalling cabinets, junction boxes and wire runs, and it's no surprise that the typical project incurs significant change-order expenses as inevitable late-stage design tweaks wreak havoc on delivery schedules.
Foundation fieldbus and other bus technologies essentially moved some I/O functionality out into the field devices themselves—easing the need for conventional I/O—but fieldbus segments are complex, and little reduction in engineering effort has been realized relative to conventional I/O practices.
The American Heritage Dictionary defines paradigm as "a set of assumptions, concepts, values and practices that constitutes a way of viewing reality for the community that shares them." And in the case of I/O, the prevailing paradigm is that I/O is hard; I/O is inflexible.
But what if it wasn't so difficult? What if constant revisions to I/O specs didn't hamstring your project schedule? What if existing I/O spares didn't limit your ability to deploy new measurement points? What if I/O was more readily available, in any flavor needed, anywhere you needed it, and at any stage during a project—even after you're up and running?
That's the essential value proposition of I/O on Demand, Emerson Process Management's new way of thinking about I/O.
The Process Landscape
To better understand the genesis of the I/O on Demand offering, it's useful to first consider the broader context of the process industries and the increasingly global business environment in which they compete.
Across the process industries, sustainability and related environmental concerns show no sign of abating, especially as they relate to conserving increasingly expensive energy and limiting greenhouse gases. New regulations are being extended to include the protection of personnel and equipment. Control system security also is becoming more important, as the perceived threat of cyber incidents mounts.
Meanwhile, increasing scale and complexity constitute a growing challenge. On the one hand, plants are getting larger. Petrochemical plants, for instance, have become petrochemical complexes. This makes sense for efficiency reasons, but the entire operation becomes more complex because of unit interdependencies. Projects, too, are getting bigger and schedules are getting compressed. Hence more engineering work is getting pushed onsite for completion, sometimes with a marked effect on final project timing, cost and quality.
Against this backdrop are a record number of industry professionals at retirement age, who as they leave are taking a wealth of experience with them. Further, some industries are pursuing strategic workforce reductions. Centralized facilities, for example, are being developed in order to move more people out of hazardous or unsafe areas. The oil and gas industry is particularly adept at creating unmanned facilities, so when someone is sent onsite to troubleshoot, a true generalist—not a specialist—is required. And in growth markets, plants often are being built where there is essentially no ready-trained work force. Further complicating matters, few experienced people are interested in relocating to these remote locales.
So, we're left with fewer, less experienced people dealing with ever more complex processes and technologies. "It's a perfect storm," said Steve Sonnenberg, Emerson Process Management CEO, in his keynote address to the Emerson Global Users Exchange late last year in Orlando as he prepared to unveil the latest iteration (version 11) of the company's DeltaV digital automation system, the S-series.
From HCD to 'I/O on Demand'
Emerson Process Management decided some years ago that human-centered design (HCD) had to be a major part of the answer to this conundrum and set out to ensure that its process automation offering helps to accomplish three primary goals: eliminate work (where possible), reduce complexity for its users (let technology do the hard part), and embed knowledge (where needed).
"Frankly, automation suppliers have not designed products built around the actual ways projects are executed and the ways plants are run," says Sonnenberg. "Advancing products features is important, but designing products around how people use them is critical."
Task analysis, notes Peter Zornio, Emerson chief strategic officer, confirms that automation design is engineering-intensive (Figure 1). "That's all work," he says, "and one of the goals of HCD is to eliminate unnecessary work."
I/O on Demand (Figure 2) is essentially the result of Emerson's HCD development approach applied to I/O. It consists of a collection of new technologies as well as a range of HCD improvements all aimed at affording customers the greatest degree of flexibility in their I/O decisions with the least amount of effort and risk.
"I/O on Demand is 'what you want, where you want it, when you want it,'" continues Zornio. "This is an automation breakthrough that eliminates the intensive pre-engineered work associated with I/O."
Electronic Marshalling Streamlines Work
While I/O on Demand promises usability and labor-saving improvements for almost any choice of I/O approach, perhaps the most transformative innovation for project work is the practice of electronic marshalling.
For conventionally wired instrumentation, electronic marshalling allows users to land field cabling wherever there is an available terminal block in the marshalling cabinet—regardless of signal type or control strategy. Each terminal block is set up to receive a single-channel characterization module, or CHARM, which includes the A/D converter and associated signal characterization for that point's particular type of analog or digital I/O signal. Each I/O point is then digitally communicated via the marshalling cabinet's DeltaV backplane—and can be associated with any control strategy in any of the system's DeltaV controllers.
The effort and cost savings potential is enormous, because the manual cross-referencing of each incoming pair of wires with the appropriate I/O card is effectively eliminated—along with the requisite "spaghetti" wiring, extra terminal blocks and cabinet space. Further, because signal characterization is done on a single-channel basis, flexibility to accommodate late stage design changes is greatly enhanced. On a typical capital project, Emerson estimates that electronic marshalling could result in 32% reduction in DeltaV controllers, a 40% reduction in cabinet footprint, and a whopping 90% reduction in intra-cabinet wiring relative to conventional I/O practices.
Redundant Wireless Boosts Flexibility
A second important aspect of Emerson's I/O on Demand approach is the addition of redundancy to the company's Smart Wireless infrastructure offering. Redundancy will allow an increasing number of traditionally wired I/O points to go wireless—for incremental monitoring as well as for closed-loop control, Emerson believes. This will have a profound impact on the design of new facilities as well as the ability of brownfield plants to easily implement new measurement points and asset management strategies.
"44% of process control inputs can be wireless with no difficulty, and for a greenfield plant that's a savings of 7% overall," says Duncan Schleiss, Emerson vice president of platform strategy. "Getting rid of wires eliminates most activities associated with wiring design and installation," Schleiss adds. "Poof! Cabinets, wire, terminations, cable tray design, fusing, installation drawings and a host of other activities are simply gone."
Reducing Fieldbus Effort and Cost
Emerson's HCD effort also took a hard look at Foundation fieldbus and found that substantial improvements could be made in how fieldbus is done. "Foundation technology requires third-party power supplies and power conditioners—along with the necessary engineering and wiring and cabinet space," Schleiss explains. "And if you wanted to get at the bus diagnostics, you had to jump through OPC and RS485 hoops in order to get the information into the control system."
"With DeltaV S-series and I/O on Demand, we've integrated the power circuitry with the H1 card itself," Schleiss says. "Third-party power conditioners and dedicated power supplies—and the engineering that went with them—are a thing of the past."
Citing a recently completed project consisting of some 2,500 Foundation fieldbus segments, Emerson estimates that total project cost could have been reduced by some 7% using the new I/O on Demand approach. "Five thousand H1 power conditioners, 32 H1 power cabinets, along with their design and documentation, and all that factory and on-site wiring," lists Schleiss. "All gone!
"But we also integrated diagnostics. So now the maintenance staff can wait for the DeltaV H1 card to notify them of a problem on the physical layer, such as low voltage or high current. Easy! It's all integrated!"
Safety I/O Leverages HART Data
Emerson also has addressed flexible I/O considerations in the modular, distributed architecture of its safety instrumented system, DeltaV SIS. Fully configurable I/O for any type of signal, the ability to add incremental logic solvers at any time, and scaleability from 16 to 30,000 I/O points all contribute to increased flexibility, improved robustness and the elmination of single points of failure.
Further, the integration of DeltaV SIS with the DeltaV basic process control system (BPCS), allows users to leverage SIS I/O information to make better operations decisions.
Error-Proofing Conventional I/O
Even the DeltaV system's "conventional" I/O hardware has evolved to make life easier with the new S-series. Patent-pending heat dissipation technology allows for a completely enclosed shell (no vents). This prevents particles—or an errant screw—from entering a card and short-circuiting electronics.
And the new S-series hardware also offers "easy-on-hard-off" installation, which means there are no screws needed to install a card onto the backplane, yet releasing one requires pushing an out-of-the-way release button on top of the card.
In the final analysis, I/O on Demand spans both revolutionary new technologies as well as the sum-total of myriad human-centered design innovations—all in the name of shifting the I/O paradigm. Now, I/O doesn't seem quite so hard, does it?