Modular Systems for Industrial Automation
For Control Systems, Put the Focus on Innovation, Not Integration
Rather than try to create control systems by integrating disparate parts, which then must be configured, tested and separately programmed, engineers would do better to start with an integrated high-performance platform and then concentrate on creating innovative solutions in software.
BY BRIAN PHILLIPPI, PRODUCT ENGINEER, NATIONAL INSTRUMENTS
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Today’s control engineers are tasked with increasingly complex challenges and face incredible pressure to simplify system designs. To keep pace with this heightened complexity, advanced technologies have emerged that make it possible for control engineers to overcome common challenges. From banks of relays to programmable logic controllers (PLCs) or programmable automation controllers (PACs), these tools traditionally help develop solutions. Although inevitably new systems become too complex for the available technology, so control engineers need to create custom solutions with the combination of several tools. It is from these solutions that advanced technologies continue to evolve to simplify and create efficiencies.
One of the latest examples of this is the PAC, which offers processor-based computing with the reliability of a PLC. Based on increasingly complex challenges, sometimes traditional PACs cannot keep pace with advanced technological needs. To solve these challenges, control engineers have started adding custom hardware to high-powered PACs to ensure tighter control, integrated monitoring or custom communication. By creating a custom solution, control engineers can typically solve the problem, although they spend a significant amount of time creating or iterating on the tools used to innovate rather than focusing on the innovation itself.
There is a clear trend toward systems that are dynamic, complex, distributed and interconnected. Systems that bridge the cyber and physical world are known as cyber-physical systems and include applications such as smart machines or smart factories. Of course, cyber-physical systems applications are all around us and include applications beyond the industrial automation industry, such as the smart grid, vehicle traffic networks, smart buildings, cooperative robots, telecommunications, automotive systems and avionics. These systems often require a combination of advanced control, data acquisition, condition monitoring, machine vision and advanced motion. In addition, multiple systems need to communicate and interact with each other and the outside world to work most effectively. This concept is commonly understood as the Internet of Things (IoT). To keep up with this accelerating trend, engineers cannot continue to spend time piecing together disparate systems made of PACs or PLCs and custom hardware. Instead, they must focus on innovating advanced systems to solve today’s grand engineering challenges.
Fortunately, there is a better way to harness the flexibility of custom design while still enjoying the benefits of off-the-shelf hardware like a PAC or PLC. This system combines the flexibility of a user programmable FPGA with the reliable nature of a PAC. This may sound unfamiliar to control designers who are more accustomed to ladder logic than logic gates, although all PACs, PLCs and embedded controllers contain processing elements. Some even contain FPGAs or ASICs used for signal processing and timing, though the chips are not user programmable. These different processing elements are analogous to a basic tool like a hammer. When walking down the tool aisle at the hardware store, a breadth of hammers hang on the wall. While most of these could serve other hammer functions (e.g., driving nails or breaking apart objects), it is critical to use the right tool for the job. PC-based automation is like a general-purpose claw hammer, meaning, it is versatile enough for most applications but it is deficient in more advanced operations as it is too harsh to properly function as a dead blow mallet, too light to act as a sledge and too small to serve as a good framing hammer.
For a broad range of applications, the standard floating point processor is suitable, although it falls short with applications that require high-speed timing, triggering, tight latency, fast control loops or custom protocols—this is where a user programmable FPGA is beneficial. Floating point processors can also be used for signal and control processing, however these are costly compared to an FPGA or DSP used for repetitious algorithms. While FPGAs are good for processing-intensive algorithms, they are limited in runtime flexibility. It is the combination of these processing elements combined with the user’s ability to program them that make new PACs, PLCs and embedded controllers an ideal foundation for a platform.
Meeting the Challenge
Although there have been tremendous advancements in technology, the trend toward cyber-physical systems presents a real challenge. As the pace of change accelerates, newer, more complex technology emerges faster than ever. Many organizations are falling further and further behind the technology curve, as achieving high-quality results is increasingly expensive and the vast majority of custom development time is allocated to low value tasks.
Piecing together a complex system through different vendors and custom hardware is possible, but at what cost? When the next unexpected upgrade comes around, due to a part going end of life (EOL) or a new customer requirement, control engineers are faced with a new set of similar problems. If a critical part does go EOL or vendors decide to change their communication protocols, the entire system is at risk of being compromised. When this occurs, control engineers must solve a similar set of challenges every time based on a small piece of the system changing. In addition, creating and maintaining a system like this requires large specialized teams that are both costly and inefficient, as each member of the team must become an expert in a certain piece of the system, including domain experts, VHDL programmers, test engineers, validation engineers, documentation and support.
System designers can look to the mobile phone industry to see that platforms are the key to rapid innovation. If we flash back 10 years, before iOS or Android, every phone was built from scratch. Each domain expert or app developer first had to figure out how to interact with all of the different hardware and operating systems before they could begin thinking about how to create differentiating features. As a result, the feature set was extremely limited and the most expensive phones were only feature-rich enough to check email and act as a PDA.
A few years later, Apple did something revolutionary—they created a single platform that eliminates the need for a designer to solve low-level tasks like repeatedly interacting with different hardware. Instead, this platform-based approach helps designers focus on innovation through software. By simplifying the hardware design, developers can use many of the same software building blocks to focus on differentiating a portion of the system. Apple could upgrade the hardware, provide new sensors and more processing power, and allow the software to evolve seamlessly with the hardware. Over a million apps later, domain experts are still discovering new ways to innovate. With a unified platform, the same approach can be applied with industrial automation, which makes it possible for control engineers to focus on innovation rather than integration.
Applying the platform principle to industrial automation also gives a new meaning to the term “modular system.” With a platform, the hardware and software are modular and reusable. This means engineers can save development time by reusing many of the core software blocks to build a system, which makes it possible to spend time innovating in places where they can create differentiation. A modular hardware and software platform integrates many of the previously disparate systems into a single system to innovate upon. This approach also simplifies custom design because it allows domain experts to work on the software and hardware development without a computer science or VHDL background. In addition, domain experts can tap into a worldwide network of system integration partners that are skilled in providing startup assistance, training and support. This platform-based approach is available and it includes customizable off-the-shelf hardware that combines the reliability and control of a PAC with the flexibility of an FPGA.
Platforms are proven to simplify the complexity of system design while increasing efficiency. One such platform is available with the NI CompactRIO software designed controller, which is based on the NI LabVIEW reconfigurable I/O (RIO) architecture. This tightly integrates a real-time processor with a user programmable FPGA that is connected to modular I/O and programmed with NI LabVIEW system design software. This powerful platform facilitates rapid algorithm engineering and openly supports multiple models of computation. Even more, the hardware and software platform is organized around an agile, platform-based “design V” methodology with integrated simulation and verification tools that reduce development cost and risk while facilitating high-quality results.
An example of this platform used to design complex smart machines comes from the collaboration of Viewpoint Systems and The Gleason Works (Figure 1). These companies created a smarter machine that defied the conventional approach to gear lapping. Instead of relying on passive physics to lap the gears, which would lead to a tradeoff between refined gear surfaces or spacing errors, Viewpoint and Gleason created a smarter machine to achieve the best of both worlds. Using advanced order analysis to monitor and control the lapping process, they were able to produce higher quality gears in 30 percent less time.
Using a platform-based approach, Viewpoint Systems and The Gleason Works created a smarter machine and significantly reduced development time.
NI’s platform-based approach of combining off-the-shelf CompactRIO hardware and LabVIEW software continues to expand with the new CompactRIO performance controller, which integrates the latest technologies including Intel Atom dual-core processors and Xilinx Kintex-7 FPGAs (Figure 2). With this powerful processor, engineers can simplify the complexity of their system by adding vision acquisition and processing capabilities. In addition, with support for an embedded UI and a built-in display port, engineers can further simplify their system by driving their local HMI directly from the controller. This new controller is suitable for applications in harsh environments and provides flexible, high-performance data transfer with modular C Series I/O. By using a platform-based approach, engineers can port code seamlessly while benefiting from the latest technology.
The NI CompactRIO performance controller is the latest realization of a next generation hardware and software platform.
With industries such as steel milling, energy, transportation, mining, textiles and semiconductor, the need for smarter machines is driving the demand for improved machine control design technology. PACs and embedded controllers using the latest hybrid processing technology can help advance and simplify machine design by shifting the architecture from several disparate systems mixed with off-the-shelf and custom technology to fewer, more consolidated software-designed controllers. This next generation platform of embedded controllers will not replace many of the old stalwarts of the process world. Rather, these controllers are ideal for the next generation of smart machines and are best suited for more advanced designers looking to get to market faster using a simplified architecture.