Everyone's looking for shortcuts. It's a primary preoccupation of modern life and a cornerstone of business and industry. Part of always doing more with less, of course, includes moving production data faster and more efficiently from process applications, field equipment and plant-floors up to decision-makers and enterprise levels.
In the past, this required running data from sensors, instruments, transmitters and I/O modules through dedicated components, controls and networks that—even though they've evolved from using point-to-point hardwiring to fieldbuses and Ethernet—are showing up as increasingly inflexible. Some process users and system integrators report that adding devices and functions to existing systems, and even making adjustments, typically requires lengthy and complex reprogramming and reconfiguration, if they can be done at all. Think of it as road construction added to traffic jams.
Finding the fast lane
"We're in the process of monitoring several hundred variable frequency drives (VFD) that run the kiln fans and setting equipment at an architectural brick manufacturer because some of the drives previously had failures," says Steve Beck, chemical engineer at Huffman Engineering, a CSIA-certified system integrator in Lincoln, Neb. "We thought about adding a PLC to get the data to the SCADA system, but we also wanted to limit costs, so we added an OPC-UA server, Ignition SCADA software from Inductive Automation and an embedded Ethernet switch/adapter, which can communicate directly with the VFDs. We initially replaced 20 of the drives, and this new solution has already saved about $10,000, not including the labor saved by not having to install, configure, program and get power to another controller. We're already looking to expand to monitoring more drives. If we build out the whole plant, the savings could be six figures."
Though Huffman's VFD project at the brick plant only involves monitoring at present, Beck adds it could eventually be used for control, too. "We're not changing controls yet. It would depend on the success of the monitoring project, but we could bypass the existing controls, and do control with the Ignition SCADA software," says Beck. "We could write setpoints to the parameters in the VFDs instead of writing to the usual PLC, and this would let us use Ignition to perform control functions. Other similar arrangements could do the same, such as using a simple protocol converter with software like Wonderware's InTouch or System Platform, or Kepware's Kepserver. There's not much documentation about how to do this, so it's also important to test hardware and software you're considering. We set up a bench test for monitoring the VFDs, and checked that Ignition, OPC-UA and the Ethernet switch would work before installing them at the factory."
Colin Geis, product management director at Red Lion Controls, adds that, "The IIoT is evolving quickly and can be classified in a few stages. At first, IIoT was seen as a data visualization tool in the cloud. Data would be transmitted to a cloud repository, and the IIoT platform would present a data dashboard allowing anybody, anywhere to see system data easily. These cloud dashboards could be considered "IIoT v1.” Next, IoT v2 took the data visualization and added intelligence, reporting and alarming, which allowed more autonomous operation, notifying if a system or process outside of programmed conditions and didn’t require an operator to monitor screens 24/7. Now, IIoT v3 is opening the way for distributed control, or bidirectional control with systems and processes. This phase of the IIoT is expanding on data dashboards, centralized alarming and also creating a feedback loop with the edge of the network. While some customers are allowing the feedback loop control equipment, more customers are simply allowing this feedback loop to modify a local database in the field (e.g. confirming that an alarm was received or an action was taken by the cloud platform).
"Another practice we’re seeing is having edge devices alert and alarm locally based on their programming, even as they’re communicating information upstream to a cloud platform where further action may be taken. Customers must place a large amount of trust in their equipment and network to allow for full autonomous control of their equipment by an IIoT platform, and this hybrid model gives customers greater confidence. More customers asking questions about this functionality, and our equipment is capable of performing these tasks, but it's still a little early to call it mainstream. Customers are deploying more edge control with IIoT connectivity because the visibility to the system and process has improved so much, but it isn’t standard practice to deploy platform-driven edge control yet."
Stephen Neuberger, CEO of Krohne Group, adds that, "Users need standard, uniform, open communication channels to participate in the IIoT without compromising safety and availability. Likewise, modularized and decentralized instrumentation of sensors is allowing them to send data directly to plant enterprise resource planning (ERP) systems. We're not saying the DCS is going to disappear, and it can't because real-time control can't be in the cloud. However, there have to be some added paths for clients' information to take, which improves their ability to add value, and achieve individual production with all the advantages of mass production."
Desperately seeking detours
Just as gridlocked drivers fantasize about cruising on the shoulder, users and integrators have long sought similar ways to get around the networking snarls and data delays up ahead. However, though they could dream, there was no fast lane due to scarce resources, network bandwidth limits and other constraints, which have only recently started to give way to new pathways.
"In our circle of control users, we're all very conservative, but we accept that we must get data from plant floors to businesses. We've worked with custom applications and data collection for many years, but there's a growing tendency to believe that we can't continue with proprietary software, which was a typical solution practice in the past," says Michael McEnery, president of McEnery Automation, which is a CSIA-certified system integrator in St. Louis. It serves mostly large beverage manufacturers and their batching, recipe management, filling and canning applications. "We try to support older operating systems, but keeping up with traditional technology is just getting to be too costly, and users want standardized operating systems, hardware and security.
"Plant managers at one sewer district want to see operations like well levels on their tablet PCs and smart phones, so we're putting together a quote to take their data that's now in a GE iFix historian, and put it in a best-fit application that's cost effective and reliable. Fifteen years ago, we did custom databases and web pages for monitoring and maintaining valves, motors and other equipment, but we don't prefer that approach anymore. Now, data from historians such as Rockwell Automation's FactoryTalk Historian, OSI PI or Wonderware Historian can be delivered by off-the-shelf reporting tool clients that easily integrate with browsers on PCs, tablets and smart phones. We're also seeing more clients considering IIoT and big data, but there’s still more talk than action."
McEnery adds that phenomena like IIoT and big data are forcing process engineers and system integrators to make some mental shifts. "As engineers, we're supposed to be as efficient as possible, including how much memory we use and data we gather," he explains. "If we didn't need specific data, we didn't capture it because of cost. However, these days, data and memory are a lot cheaper, so the new mindset is to collect as much as possible, and then use analytic software to see if it's useful later."
Mike Boudreaux, director of the Connected Services program at Emerson Automation Solutions, adds that, "A wide swath of users are recognizing that new analytics, applications, software and other capabilities can be enabled by connecting to existing systems. So, while getting DCS data still makes sense, they can also deploy wireless and other network points that aren't needed for control and safety, and get valuable pressure, temperature and flow measurements. Many process applications don't need millisecond or 1 second updates, and instead have updates of a minute or more, so some users are looking outside the process control network to develop a 'process data network' with many of the same devices. For example, Emerson's wireless pressure gauge now has an electronic sensor and digital wireless instead of the traditional mechanical device with dials."
Of course, once this data reaches an Ethernet network, it can be delivered immediately to the enterprise, the cloud and other server-based applications for analysis and performance/reliability monitoring on laptops, tablet PCs, smart phones and other interfaces. "Emerson and other providers can host applications, and even do monitoring for clients as a service," adds Boudreaux. "It's a lot like a cable TV subscription. However, this only monitoring; we're not doing control and safety functions in the cloud, though wireless for monitoring is proven, and more efforts to leverage the cloud are happening."
History of shrinkage
While the idea of skipping the PLC or DCS might be unthinkable to many engineers, operators and managers, this concept is just one chapter in the epic story of faster, more powerful, less costly and smaller computing devices in industry and elsewhere. The journey from clunky hardware to virtual software seems inexorable in all cases.
"We should remember that PLCs have shrunk a ton since they were first introduced," says Michael Robinson, national marketing manager for projects, solutions and services at Endress+Hauser. "The first 8-bit PLCs in the 1970s were big and very costly, but by 2012, they were 32- or 64-bit, fit in your hand, and cost only $500. Ten years ago, getting data from instruments was cumbersome and expensive with analog inputs and outputs, but for today's users that just want to visualize or analyze their data, it may still be difficult to integrate and network several plant controllers. Everyone uses the same Ethernet cables now, but the fieldbus protocol wars of the mid-1990s still haunt us today, so we still have five communication cards talking different languages.
"Nevertheless, many users want to aggregate and visualize data, and not necessarily do control, or deal with the extra costs of adding PLCs and HMIs. They just want to monitor their flows and tanks, and communicate that data to the cloud. These efforts began with HART, Profibus and Ethernet gateways and WiFi or cellular modems. We also made chart recorder replacements, Memograph and Ecograph, which brought instrument data in, and did local visualization. Now, it's just shared with the enterprise via the cloud, and the gateways are called IoT or edge devices, some of which can run open-source code like Python to manipulate their data streams. As result, many users ask themselves why they need a PLC if they're not doing control?"
Dave Emerson, director of the U.S. technology center at Yokogawa Corp. of America, adds that, "The influx of IT into the automation space is increasing. It's obvious, just like when computing went from Unix to Windows, and the same is happening to distributed controls. If you want to add I/O points to a DCS then you typically need to call a specialist, but new, low-cost sensors, wireless and edge devices are getting data to the cloud faster and at less cost."
Bruce Billedeaux, senior consultant at system integrator Maverick Technologies, a Rockwell Automation company, adds that bypassing PLCs can be accomplished. In fact, doing it was one of the initial visions of the HART protocol, which was developed in the mid-1980s, and originally sought to perform distributed control through a 4-20 mA loop. "However, HART was too far ahead of its time back then, and users couldn't handle the communications needed," says Billedeaux. "Now, HART is getting more of backbone it needs, and we're going to become ubiquitous as more controls move to the cloud."