Open-source computers arrive for monitoring and control

Sept. 26, 2017
Raspberry Pi, Arduino and other computers on open-source silicon boards are on the way for do-it-yourself monitoring—and even control.

Don't stop us if you've heard this one. "One of our co-op students this summer was looking for the Raspberry Pi he was using to set up an HVAC damping system, and asked the 25 people at our daily huddle," says Sandra Buffett, P.Eng., founder and CEO at Jordan Engineering Inc., a CSIA-member system integrator in Niagara, Ontario. "After the huddle, one guy asked, 'What's this pie everyone's talking about?' "         

(Cue drum-and-cymbal.) Ba-dum, chhh!

While unfamiliar terms are quickly cleared up, learning new concepts and technologies usually takes longer. Even those in-the-know at Jordan aren't all Raspberry Pi experts yet. "We began learning about it when one of our chemical compounding clients put one on the back of a wall-mounted TV monitor with an Ethernet jack and WiFi to display alarms and notifications on their plant floor," says Buffett. "This let them go from a typical LED display scrolling text, and upgrade to more graphics, colors and maybe dashboards, and gain those capabilities with less expense."

Buffett reports some of Jordan's engineers bought a couple of Raspberry Pi kits and adapters two years ago, started playing with one, and gave the other away at one of its annual automation workshops. "We're very relationship-based, and we partner with our clients for a long time," explains Buffett. "We've been holding our workshops for the past 14 years. They usually include staff presentations and project demos, and give everyone a chance to sit down and swap useful information. This past May, we did workshops in three cities for the first time, and gave away Raspberry Pis to 150 clients with help from Schneider Electric Canada, which has been a close partner for 18 years."

During the workshops, Schneider Electric conducted a lab for attendees to explore Raspberry Pi. "To open their minds to its possibilities, groups at each table came up with different ideas about how to use Raspberry Pi, such as monitoring the weather, energy prices, interest rates and inventory costs, which could empower their operators by helping them make better decisions on the best times to make their products," adds Buffet. "Our co-op student completed the design of his demo project to dampen the HVAC system in a two-story house, and deliver more heat to the lower floors in winter and more cooling to upper floors in summer.

"We're not using Raspberry Pi on plant floors or for critical or safety controls. It's best for monitoring and non-critical functions right now, and making small improvements you couldn't do otherwise. Many users like us have little applications that used to be prohibitively expensive to monitor and control. Well, now we can do them. We don't think of Raspberry Pi as taking away from PLCs and DCSs because it can also do monitoring and provide alerts to them."

Alain Zagar, technical sales manager in Schneider Electric's Process Automation division in Canada, reports his team has been running its seminars, "2017 Innovation Talks: From Sensors to Business Sense," across the country, and that Raspberry Pi has been part of its efforts to show users how they can begin to take advantage of the Industrial Internet of Things (IIoT). "Clients are asking how they can implement the IIoT, so we felt is was a good time to show how Raspberry Pi and other technologies can tie things together and do it securely," says Zagar. "The public thinks of Raspberry Pi is an accessible engineering tool, and partnering with Sandra and Jordan Engineering let our users get some hands-on experience, better understand Schneider Electric's EcoStruxure IoT-enabled system architecture, learn to leverage the IIoT with the assets they already have, and achieve business benefits."

Long time to overnight success

New names and learning curves aside, pretty much everyone had to know this was coming. The moment analog signals and data began to be sliced and diced into strings of digital snapshots 40 years ago, the eventual emergence of computing with open-source software on generic silicon boards for monitoring and control was inevitable. Just as manual, pneumatic and relays gave way to programmable logic controllers, those PLCs—like all computers—began to shrink in size and price, gain power and capabilities, and widen and accelerate their networking with emerging Ethernet cabling and Internet protocol (IP) communications to the web, cloud-based services, IIoT and whatever comes next.

Likewise, just as other wiring and devices become more commoditized and as software becomes more open-source, some process engineers, system integrators and developers are also asking why they have to pay several thousand dollars for controllers with only $40-50 worth of hardware inside. Just as they're asking why their plant-floor devices and process systems can't offer the same features and functions as the apps on their tablet PCs and smart phones. This is coaxing embedded computing boards out of the shadows, and enabling developers to begin freeing them from proprietary configurations and formats—often at the request of their end users, as was the case at Jordan Engineering. So, while it can seem like Raspberry Pi, Arduino and similar devices came out of nowhere, these embedded and generic boards actually have a long history in the computing field.     

"The typical PLC today can cost $5,000-$7,000 and can help run a whole plant on one server with its I/O connections to field devices via its dedicated backplane, but the computing power inside that PLC is typically only worth about $100," says Abhijit Jog, vice president of projects at Panacea Technologies Inc., a CSIA-member system integrator in Montgomeryville, Pa. "Now, Raspberry Pi and similar computers are popular, but these technologies have existed since microcontrollers first become available in the early 1980s when PLCs and many types of proprietary machine controls emerged. In fact, I did my B.S.E.E. project at KLS Gogte Institute of Technology in India by designing a basic board and developing a two-axis control program for positioning a drilling device.

"For a long time, it was just easier to use standard controls from large, individual suppliers, but lately all I/O is distributed and connected to PLCs via Ethernet, so there's more flexibility and no reason to keep brains in one box because they can be in a server on a rack or in the cloud. What's been lacking is a server-based machine that runs PLC-style software in a deterministic way, but Dell and other manufacturers have standardized servers that just need the right software to run like a PLC, and Codesys has come out with scalable control software that's very flexible, so we'll get there sooner or later."

Codesys is a development environment for programming PLCs using the IEC 61131-3 standard. It recently launched an adapted control runtime system, Raspberry Pi SL, which contains a Codesys control application for all Raspberry Pi devices, including its compute module and extension modules Raspberry PiFace Digital, Raspberry Pi Camera and several devices/breakouts with SPI, I²C or one-wire communication interface.

Benson Hougland, vice president, marketing and product strategy at Opto 22, adds, "The notion of massive I/O systems home-runned to a central PLC or DCS is dated thinking. Today, I/O termination and conditioning is occurring remotely, or at the network edge. Now, users can run a Raspberry Pi on edge devices for remote I/O at very low cost. Plus, moving process and plant data through a $35 Raspberry Pi or other single-board computer proves that IIoT can work without having to use a $5,000 PLC. In fact, our engineering vice president, Ken Johnson, challenged his team to prototype a vision system to test and confirm LED illumination for our newly developed control system, which could have required thousands of dollars worth of software. However, our intern, Terry Orchard, used a Raspberry Pi 3 running Linux software programmed with Python language to manage I/O, a camera, the video feed, software library and RESTful application program interface (API), and completed the prototype proof-of-concept in four days for less than $100."      

Jaroslav Sobota, head of customer success and control system engineer at Czech Republic-based Rex Controls, adds, "We've been considering using Raspberry Pi for monitoring and control ever since it was introduced to the market, but we got serious about it when model B+ was released in 2014. Our answer is a clear 'yes' that Raspberry Pi is a perfect platform for programmable data loggers, data bridges or communication gateways. Especially in this era of the IIoT and Industrie 4.0, the Raspberry Pi definitely has a place in the world of PLCs, PACs and IPCs. However, one must understand that using Raspberry Pi in industrial environment might be a bit tricky, mainly because of its uncommon 5 VDC power supply and microUSB power supply connector. It also does not have any standard industrial interface like RS-485 or 24 V-tolerant inputs."

Board basics for process

While it might initially seem foolish to attempt monitoring, let alone process control, using a generic computer board, Doug Reneker, just-retired senior manager at broadband access supplier ARRIS Technology Inc., and technical writer Peter Welander recently collaborated on a demonstration project that employed a cigarette pack-sized Arduino Uno board, an Adafruit shield stacked on top to help with the display, one sensor and one actuator to start a pump, and a flowmeter to measure water flow.

"There are a lot of maker boards available like Raspberry Pi, Arduino and Beagle Bones, but we decided Arduino would be easiest because of the simple environment that its code runs in," says Reneker. "We programmed a start-up routine written in C called 'setup()' that gets executed once at the beginning, and a second routine called 'loop()' that's called repeatedly once ‘setup()’ has completed. Nothing else goes on. Next, we used an algorithm to read the sensor in 'loop,' calculate the difference with a setpoint, apply proportional and integral terms, adjust both in about 100 milliseconds, and create a control report."

This simple setup includes a 3051SF Rosemount flowmeter borrowed from Emerson Automation Solutions, Fisher Gen2 easy-Drive electric actuator that works with the Arduino board, Everbuilt sump pump and Rhino 24V, 4A, 100W power supply, PVC pipe and a large water bucket. This is a very basic process control application, of course, but Reneker reports there were several complications in arranging the industrial controls to work with the $20, open-source board (Figure 1).

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"Industrial controls require 4-20 mA current loop, but Arduino senses 0 to 5 volts for analog input, and drives 500 Hz pulse-width modulation for analog output" explained Reneker. "While the programming may be easy, pulse width modulation (PWM) at 500 Hz doesn't look at all like a current loop."

Reneker adds that he and Welander also added a BRX PLC from Automationdirect in the project's second phase to manage the display and HMI on their water pump system. While the PLC didn't interact with the Arduino, they were able to compare implementing each. "With Arduino, we had to write the software for the setup() and loop() functions, build its circuit and LCD display, bracket with potentiometers, add other hardware, secure the flowmeter, and hook up the PLC for the display," says Reneker. "With the PLC, it's more for the all-encompassing factors of an application. I programmed it with a laptop and the supplier's software, and it already had PID instructions inside. However, if you're not a skilled automation person, you'll need to find someone to program in ladder logic, and set up alarms, communications and other functions."

Because of the added programming and configuration effort that Arduino requires, Reneker adds it's important for potential users to answer three questions before trying to design and build it into an application:

  • What are the actual functions that need to be performed? For example, is flow being monitored, or does it need to be controlled?
  • How will it verify that its functions are performed? Is a display enough, or is some kind of external supervision needed?
  • Once monitoring and/or control tasks are automated, what kind of data acquisition and archiving is needed?

"Arduino's memory is limited, but you can add infrastructure and communications to it—even a cell phone adapter," adds Reneker. "We couldn't find a current loop interface, but there are so many makers involved that's it like browsing the items at a flea market. You just need to determine how you're going to use it, and learn what's standard for that function.

"Arduino is ubiquitous, and that's what makes it attractive. Arduino, Raspberry Pi and the other boards have huge communities of users you can turn to for advice. Many kids even have a good idea how to use it. So when we write code, we know what to expect. We can see the voltage on a pin, and provide inputs and timing. The entry level for understanding Arduino is low and the process is gentle. You can get in and run with it, and build on pieces around if for all kinds of tasks.

"However, you may also have to decide if you're buying into some added problems. Do you have to consider safety requirements and certifications? Do you have the right electrical isolation? There are many dilemmas like this to settle. How much do you want to build and program yourself? How many features and capabilities do you want to buy? You just have to decide how much of the wheel you want to reinvent."

[For more coverage of Reneker and Welander's project, read "Arduino vs. PLC for industrial control." A video about it is at]

Ethernet parallels computing future

Before approaching board-level, open-source computing, some potential users are examining other technologies that developed along similar lines, and found that Ethernet's evolution was instructive. At first, Ethernet was only in office and physical plant systems, but not on the plant floor, because it wasn't deterministic or rugged enough. However, a few users began snaking Cat 5 cables over to a production line or process application to "just gather one signal or value." In a few years, Ethernet was everywhere on the plant floor, and board-level computers are likely going to do the same because they have the same advantages and momentum. In fact, many types of software started out as custom, proprietary programs that were written and programmed within individual companies, but over the years, solutions for doing the same tasks emerged as commercial, off-the-shelf (COTS) products, and many of these gave way to open-source programs that are freely available to all.

"In the mid-1980s, I recognized that Ethernet wasn't deterministic, but I played with it, and used it for some data acquisition tasks," says Rick Caldwell, president of SCADAware a CSIA-member system integrator in Normal, Ill. "Because Ethernet communicates by speaking, listening for collisions, and speaking again if there were any, we didn’t consider it for control. Later, Ethernet switching hubs (switches) allowed communications on Ethernet to be more practical in the industrial environment, since each port was a separate collision domain. This allowed each device to be on its own collision domain minimizing data collisions between devices. This still isn't deterministic, but it is fast and reliable. In the early 1990s, someone came up with Ethernet-based I/O, and we connected each I/O block to a separate port on the Ethernet switch. I was the rebel back then, but now our engineers are asking if they can try to use Raspberry Pi or similar boards in our status lights and wireless sounders, and I have to be the conservative one that asks if their I/O is sufficiently isolated."

Caldwell adds that when SCADAware developed its StatusLight line of Andon stack lights to work with its StatusWatch OEE reporting software in 2008, it bought $250 ARM boards with proprietary field programmable gate arrays (FPGA). "One reason our engineers favor trying Raspberry Pi is because it has hundreds of megabytes of RAM, video and an ARM processor for just $30-60. It just lacks the hardened I/O, temperature specs and vibration specs that we need."

Despite these limits, SCADAware's engineers continue to experiment with their boards, and build small monitoring systems. "Our first Pi project was a production line monitor. We combined a Pi and a photo eye to count  parts and read digital signal from the VFD to determine when the line was running," says Kevin Garman, project engineer at SCADAware. "Experimentation with new technologies is much easier in monitoring role because it’s not likely to cause downtime.  I think the Raspberry Pi is a great choice because it’s very accessible, it’s cheap, and it has a good track record. That said, it would be nice to have on-board hardened I/O and industrial temperature ratings."

Because Raspberry Pi requires a second board to handle I/O, the question is who should design and add the fasteners to connect these two boards and other support structures for board-level devices? Caldwell says the board's manufacturer should do it, but Brian Teagarden, senior engineer at SCADAware, says the board's buyers should determine how to protect it for their particular application. "Sometimes we're talking about small quantities of boards being used by small shops, and the broad availability of these inexpensive boards means we're able to easily swap them out for different manufacturers or newer models as the need arises," says Teagarden. "These boards are fun to work on and there's a lot of exciting software available, and it helps that there's a large user base out there. If you're going to use a board like a Raspberry Pi, you have to test it your own environment, and make certain it's good enough.”

Garman adds, "I think we're currently undecided about advertising our use of Raspberry Pi type boards. It seems that it could be an issue for some customers, while it might be a selling point for others."        

Panacea's Jog reports that one way to approach Raspberry Pi and its counterparts is to use them as thin-client HMIs combined with monitors and keyboards. "Most of our projects use VMware for the computing infrastructure, while using flexible HMIs," he explains. "We've executed projects to replace old, unsupported PanelView HMIs with iPads, which doesn't require us to remove the old displays. We put a QR code on the old panel, the iPad takes a picture of it, and the right display comes up on the tablet. We could also use desktop monitors as HMIs by putting a Raspberry Pi on the back and making a remote desktop connection through it, the actual software and application could be elsewhere. People coming into industry have consumer technology-driven expectations they want to drive things by their phones and their tablets , they want to know why they can't acknowledge an alarm with a text? That's why we focus on new technology because they're asking questions like why they can't do things like acknowledge an alarm with a text?

"Previously, we had individual engineering computers to work on projects, but they were often security headaches because they could be infected with USB sticks and were used to access the Internet. Now, we have virtual engineering stations running in private clouds to execute client projects , but we use Raspberry PI’s to access protected environments that only allow selected access. This is less costly than individual workstations, and it's more secure because files are automatically saved to the cloud, and there's no connection to the outside Internet."      

Protection, accessories essential

Because Arduino, Raspberry Pi and the other ARM-based devices are basically naked computing hardware that used to be embedded until they escaped from their dedicated enclosures, their first task is to "get some clothes on" that can protect them in the settings where they're going to serve. Likewise, because they're mainly raw computing capability, they typically need stack-on boards, clip-on accessories, support software and other tools that can help them cooperate and handle the applications that need their computing functions. Each board format seems to have a different name for these accessories, such as shields, hats, capes and others.

"Single-board computers like Raspberry Pi are a ton of fun, but they're fragile, and their Pi hats can burn up," says Ben Orchard, application engineer at Opto 22. "This is why Opto 22 decided to build an interface from a Raspberry Pi to industrial I/O, which play beautifully in edge devices using Linux software and RESTful API format for designing network applications and communicating with controls and software libraries." 

Opto 22's Hougland adds, "To make our solutions work with boards like Raspberry Pi, we introduced our Digital I/O Carrier Board last year, which comes in a starter kit and includes a digital I/O rack, four digital I/O modules, and Raspberry Pi carrier board. A standard 40-pin header is also provided for access to unused GPIO pins on the Pi. We're also providing alternative industry protocols, such as a RESTful API to exchange web data via HTTP and JavaScript Object Notation (JSON) data-interchange format. Plus, we're working with Node-RED ( drag-and-drop, graphical tool and the Python programming language (" Node-RED is a flow-based programming tool for stitching together hardware devices, APIs and online services. It report that it provides a browser-based editor that makes it easy to "wire together" flows using a wide range of nodes in its palette that can be deployed to its runtime in one click.

[For an educational blog post, "How to Build a Raspberry Pi with Node-Red and Industrial GPIO" by Benson Hougland, visit]

Rex's Sobota adds, "An add-on board is a must. It should allow using a 24 VDC power supply or better yet, a 10-30 VDC power supply range. This is enough for Ethernet-based solutions, such as reading data from a PLC via Modbus TCP and pushing the data to a company database or cloud service. An additional Ethernet port is handy in this case, and it can be easily provided with a USB Ethernet adapter."

Sobota adds that an RS-485 port is also a good idea. "Although some consider this interface obsolete, I believe it's going to be available at the plant-floor level for at least another decade. It's especially important for using the Raspberry Pi as an Ethernet interface for older PLCs and devices that aren't equipped with Ethernet port. A Raspberry Pi with RS-485 port is thus invaluable for integrating such older systems into ERP/BMS systems.

"Using an add-on board with direct analog and digital I/O enables even more applications. You can immediately start collecting data about productivity of machines at your factory, without modifying the existing algorithms running inside the machine. There are many machines out there whose vendors are long gone or aren't willing to modify the code, such as providing status data via Modbus registers, so using direct I/Os is the only viable approach. Last but not least, with direct I/O you can create customized wired or Wi-Fi bridges for analog and digital signals."

Likewise, Hilscher recently released its netPI industrial-grade Raspberry Pi 3 platform with onboard netX chip, Ethernet and fieldbus networking, and hardened Linux kernel for improved security. It also launched netHat Pi-compatible module with netX chip for Ethernet communications, and netShield STM32 Nucleo expansion board with Arduino-compatible connectors to support Ethernet protocols, as well as OPC-UA and MQTT.

In addition, Sercos International and Steinbeis Embedded Systems Technologies (EST) GmbH report their EasySlave Sercos III slave prototyping kit uses an Arduino board as a rapid prototype platform, shield expansion board with Sercos EasySlave FPGA, peripheral components and open-source software to create prototypical Sercos applications from which corresponding Sercos III devices are derived and implemented (Figure 2).

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"With the Sercos EasySlave, a simple and inexpensive interface for Sercos networks has already been available for a few years," says Christian Hayer, managing director at Steinbeis EST. "Now, the Sercos EasySlave kit for Arduino offers the chance to connect one’s own applications to Sercos via a simple API without major development effort. In particular, combination with the numerous shields already available from other manufacturers enables the user to perform diverse realizations of his application.”

Peter Lutz, managing director at Sercos International, adds that, “The range of products and providers for Sercos III has grown impressively in the past few years. Despite this, mechanical engineers and device manufacturers may find the introductory hurdle of implementation too high, especially in the case of niche products and small batch sizes. With the Sercos shield for Arduino, Sercos III device prototypes can now be inexpensively developed and tested in the simplest manner. Teaching and research institutions also benefit from this approach, as ideas and concepts can be implemented simply with the Arduino platform and the Sercos shield.”

Play to find opportunities

While "testing" might be a more acceptable word than "playing" to many process control engineers and other technical professionals evaluating new technologies like open-source, board-level computers, several system integrators report that play is exactly right because it allows potential users to see where these devices might be useful in their applications.

Jordan Engineering's Buffett recommends that the best way to understand how Raspberry Pi or other generic computers work and can be applied is to simply play with them. "Innovations come from this play, so carve out some time to just use them and learn their capabilities," suggests Buffett. "Later, when you're back on the plant floor or in a meeting, something will click when an opportunity comes up, and you'll recognize where Raspberry Pi can be applied. For instance, when we introduced desktop PCs running Wonderware InTouch software to a paper mill about 23-24 years ago, its staff hadn't used a mouse before, and they were very timid. So, we taught them to play solitaire to gain mouse skills and built a game with on-screen buttons, sliders, trends and numbers. This let them see what was possible with the PC and what its capabilities were, and let them visualize how they could use it to better control their process. The same is possible with Raspberry Pi today."

Rex's Sobota also advises potential users to not wait. "Go for it! Don't think about the Raspberry Pi as a standalone device but as a CPU module to build upon," he concludes. "There are already add-on boards available, ranging from prototyping platforms like RasPiBox Open+ to robust platforms like Monarco Hat. I mean it, give it a try! Raspberry Pi opens new possibilities, it gives you the freedom to build your own solutions tailored to your factory and processes with minimal budget. It gives you the freedom to decide whether to use it only in proof-of-concept stages of projects or continue using it 24/7 at floor level. Or throw it away after a few attempts if you find out it's not your cup of tea. Also, don't be afraid of Linux! There are software packages, such as Rex Control System, that allow you to program the Raspberry Pi from your desktop PC so that your interaction with Linux is minimized.

"On the other hand, always think twice about the consequences. What environment will the device operate in? Operating temperature and vibrations are known to be the most critical. What happens when the Raspberry Pi fails? Not having real-time data on displays at floor level can hurt, but certainly not as much as stopping the whole production line. If necessary, will it be possible to switch to another hardware platform without starting software development from scratch? Those are the types of questions you should be asking. In short, Raspberry Pi gives you freedom, but keep in mind that freedom comes with responsibilities."

Andrew Kling, director of software development engineering at Schneider Electric, adds, "The trend we're going to see is increasingly more generic hardware platforms with loosely-coupled applications running on top. In the past, engineers had to design tight applications and leverage operating systems (OS) to squeeze in what they needed. Now, we have ARM processors with enough computing power to drop 4 gigabytes into an application, as well as an IP stack and web services, or add dedicated cores that don't have to be related to the process side. This powerful silicon lets developers tease apart applications, OSs and hardware that used to be tightly integrated, allowing them to evolve at independent rates. These days, higher-powered CPUs provide functions right out of the box that don't need crafty programming. This lowers the bar in getting a wide range of applications onto an embedded platform.    

Everyone in the IIoT pool—PLCs too

 Ironically, even though generic board computers may seem poised to replace many PLCs, the sheer fluidity of these board-level devices and their open-source software lets them cooperate with many existing and legacy devices including PLCs, and assist them in their various plant-floor missions. For example, Zagar explains that attendees at Schneider Electric Canada's seminars used Raspberry Pi with built-in WiFi as a gateway to help Schneider Electric's M580 Ethernet-enabled PLC connect to its EcoStruxure Plant cloud securely via Modbus TCP/IP protocol. "To employ Raspberry Pi as a gateway, we used IBM Node-RED to enable it to connect to Internet protocol (IP)," he explains. "The attendees learned how Raspberry Pi can help them get information from the cloud, such as weather information or real-time energy data.

"Especially in western Canada, polling energy costs and deciding when to run equipment or not lets users bring in added or emergency generating capacity when grid power is costly. Weather can also impact operations and quality of products like kiln-dried lumber and pulp and paper, but in the past, it wasn't part of the decision process on more than an ad hoc basis. They also learned how they can pull business information safely and securely out of the box. Raspberry PI and other DIY boards are generally unsecured devices, requiring users to take many added precautions to prevent unauthorized access.  As part of the learning experience, the attendees experienced firsthand the potential pitfalls of using unsecured devices and the importance of having a cybersecurity mindset as an integral part of their system design.”     

Peter Martin, vice president of business innovation and marketing at Schneider Electric adds, "Technologies like Raspberry Pi can help PLCs by providing more technical capabilities in smaller packages at lower costs, but it's not worthwhile if we continue to do what we've always done. We also have to use these computers to increase functions, so operating assets and plants can run more reliably, safely, efficiently and profitably within a cyber-secure package."  

To help operators control systems in their plants connected by Ethernet, Michael Vermeer, product manager for IoT at Panduit (, reports it's launched its IntraVUE, Version 3, which combines with the usual data collection and diagnostics, and further organizes devices—including those enabled by Raspberry Pi—according to plant layout to physically document where they're located in the plant, so maintenance technicians can rapidly locate them.   

"The next big problem for many users will be how to deal with all the added devices, such as I/O and drives, which are already networked by Ethernet, but still isolated behind proprietary gateways. These present a barrier to centralized monitoring or mapping via standard TCP/IP communication," says Vermeer. "Users are still looking for the architectural capability that optimizes localized machine performance with global system visibility across a vendor-neutral ecosystem. Some see this being solved by IoT gateways that add control-type services onto a traditional router. Others in the automation space see PLC backplanes evolving to add Ethernet-routing capabilities, such as the Modicon M580 platform. Meanwhile, users are struggling with gaining visibility of the segmented portions of their plants.”

To give users that visibility, IntraVUE runs on a centralized server, and assembles one view of all Ethernet devices in a plant, both those that are directly routable and those in isolated networks.  To get around proprietary gateways and PLCs, IntraVUE uses WNMS-APPL Linux-based appliance with two network interface cards (NIC) that can access device networks below PLCs, check for software and microprocessors, and monitor device performance in the isolated network even when faced with PLC failure.  Vermeer reports that Panduit has recently validated the use of the Raspberry Pi 3 platform for use as an agent that can effectively perform the same function as the original appliance, when configured with IntraVUE agent software.  Basic security for the systems will be provided by passwords, encryption and systems and architectures that segment and secure the plant network from the enterprise and broader Internet.

"A standard Raspberry Pi has one RJ45 Ethernet port and two USB ports that allow Ethernet communication, so all we had to do was add a microSD memory card with IntraVUE software loaded," explains Vermeer. “When configured from the IntraVUE server, this allows individual devices on the isolated network be recognized by the Raspberry Pi, and bridged over to the IntraVUE server on the plant network, while not allowing routable traffic between the isolated machine and the plant network. IntraVUE is very passive on the network, so it monitors without creating disruptive traffic. We've been using this solution to monitor a pilot food and beverage application for six to eight months, and it's working great."

Similarly, Agustin Pelaez, cofounder and CEO of Ubidots (, reports it's developed a cloud-based service that lets users connect devices to the cloud with its firmware libraries, create visualizations using real-time dashboards, send short message service (SMS) or emails and trigger WebHooks HTTP message posts based on device data, and deploy portals or build their own applications.  

"Previously, users had to build their own time-series backend, computing environment, data retrieval and access method, data display and GUIs," says Pelaez. "We created Ubidots' point-and-click environment so they don't have to build a whole ecosystem. Users just buy a Raspberry Pi or even a more robust device, add a few lines of code from one of our 50 device libraries, and connect to the Internet and cloud for plans starting at $20 per month. This lets shop managers see their starts, such as equipment stops, energy consumption and production lines performance, without buying a costly PLC."

Innovation is inevitable

So where are all these open-source, board-level computers going? With their cheap-as-dirt prices and ever-increasing power and speed, anywhere their users want to apply them. Their presence is already multiplying in the hobbyist and consumer sectors, which likely guarantees their growth on the plant floor, too.  

Panacea's Jog adds, "Some of our engineers are active in Raspberry Pi and similar maker communities, and we see it filtering into the automation industry as well. Suppliers can't continue to sell a $5,000 device when a $100 one is available. The first company that comes up with a virtual controller running on a standard server is going to do disrupt the current business model, and do a lot of business.

"However, this also means the job of process control engineer is no longer just about controlling valves and loops. When you're managing networks, servers and cloud, you need to know a lot more. Twenty years ago, control engineers tuned loops, which got a little simpler with auto-tuning software. As we transitioned to PLCs programming them was valued more than traditional tuning skills. What's going on now is just another transition, and we can make it through this one, too."

Schneider's Zagar adds that, "I'm not really worried about board-level computers putting traditional controllers out of business. I'm excited because we can all learn and make good use of these tools. Customers are asking about the cloud because they want to improve their bottom lines, but there's still a lot of hesitation about using more DIY-oriented technologies. However, we're not talking about using them for mission-critical tasks or using them to tamper with equipment. I think DIY devices suffer because they've traditionally been used for one-off projects, so their developers and users don't think about lifecycle issues or what to do if they fail. However, that's exactly what control and automation professionals do, and tools like Raspberry Pi and Node-RED can help join the plant to IIoT and the cloud, and allow better decisions than with the usual plant data."  

About the Author

Jim Montague | Executive Editor

Jim Montague is executive editor of Control. 

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