Industrial Controllers: Past, Present and Future
Since the advent of programmable logic controllers (PLCs), various automation controllers have migrated into industrial applications, including programmable automation controllers (PACs) and today's edge programmable industrial controllers (EPICs). Increased competition among leading controller suppliers as users have more choice in terms of cost, footprint, input/output (I/O) density, fieldbus compatibility, communications, programming capabilities and processing speed .
For the market, diversity is often beneficial, but it can also be frustrating for engineers and end users. Choosing a control platform is a long-term investment with associated costs such as training and support contracts. Policymakers want to get their money's worth for the money they put in.
But before expressing support for the issue, let's take a look at how the industry is developing. What is the driving force behind the development trend of different control solutions? How do these trends work now? How will users invest in automation in the future to ensure success?
Evolution Mode of Industrial Controllers
Studying the progress in the field of automation and control over the past few decades can clearly see how some iterations of specific technologies are driving the development of new I/O and control functions.
For example, when the first I/O systems were developed, field control and sensing equipment also relied on electromagnetic and pneumatic components that were limited by physical properties that affected their useful life. Compact low-voltage components such as solid state relays are driving users to demand more options for integrating I/O directly into their systems. This led to the emergence of the first modular I/O, and at the same time, electronics companies brought high-tech computing into the mainstream. The sensitive electronics in these systems require external I/O to interact with the real world. This is the first serially addressable I/O rack, which is an alternative to rack-based I/O in PLCs.
From dedicated, independent I/O devices to modular I/O, to bus I/O, all reflect the concept of multiplexing in industrial control. Next-generation control platforms incorporate embedded I/O processing circuitry. Modules have expanded from 1 I/O channel to 32 channels, and now have I/O built into PLCs and other single devices. In some cases, with proper configuration, each I/O channel can accept a variety of different signal types.
This model shows how innovation spreads across the industry: over time, individual innovations become modular, partnering with other technologies, and then embedded in those technologies, becoming part of a new innovation cycle.
For PLCs and PACs, this mode provides smaller controllers and I/O modules. Greater computing power is achieved "per square inch" as math and programming processor functions are integrated directly into control boards and other devices such as I/O, transmitters, and network gateways. Over time, the same pattern is reflected in the migration of new embedded communication interface and protocol standards to controllers.
Fusion of different technologies
The trend of mutual integration is intertwined with the integration cycle, and technological innovation outside the industrial control market has gradually entered the controller. Looking at the history of bus I/O, you can see how this trend has led to the development of new controller functions.
From serial bus I/O, there are parallel I/O buses and other solutions that allow mini and microcomputers to interact with I/O. This also inspired the idea of developing a stand-alone I/O communications processor, which separates the I/O from the computer, allowing any computer with a communications port to interact with it.
As I/O modules and processors improved, early hybrid controllers also provided analog signal processing capabilities that were only available in distributed control systems (DCS) at the time. Since the original purpose of ladder logic programs (a PLC programming language) was not to handle analog data formats, this led to the creation of a new programming language for hybrid controllers.
Then, low-cost alternatives to the IBM PC began to flood the market. Since the PC is the primary control function of the hybrid system, reliability concerns have arisen. It was significant for the supplier to develop an industry-hardened alternative that combined the I/O, networking, and programming components of earlier hybrid solutions into a single system that would later become a PAC system. A PAC uses the same processor as a PC and can provide a feature set that fills a niche between low-cost, PLC-based discrete control and high-cost, DCS-based process control.
Innovations in high-tech enterprises and the personal computer market have brought opportunities for the development of industrial control. This trend is starting to accelerate with the increasing convergence of the operational technology (OT) and information technology (IT) domains. Take, for example, the wave of mobile solutions that has emerged in recent years. It's also reflected in the push to support big data, cloud analytics and machine learning, technologies born outside the realm of industrial automation.
Future-proof controllers
As the trend toward deeper technology integration, greater convergence between industries, and greater connectivity between devices and systems continues, what will the controllers of the future bring us?
How should engineers be selected to ensure they can keep up with technology trends and help businesses get the most bang for their buck? The following 3 suggestions can help manufacturers choose the right control technology to achieve their goals.
1 Focus on design rather than function
Knowing that technology will improve over time and become more tightly integrated and embedded, it is necessary to prioritize investments in control systems that cannot change easily or quickly. Engineers need to emphasize the architecture of the control system, not some of today's eye-catching features.
2 Look for external innovation
If engineers design systems that can evolve over time to keep pace with digital transformation, reducing maintenance and rework, it can impress end users, who will remember that the technology that determines the future often comes from outside the industry .
3. Keep an open mind
The battle for proprietary technology market share hinders innovation, while support for open standards opens up possibilities for everyone. Connectivity is one of the target metrics of Industry 4.0, and as connectivity increases, engineers need to invest in technologies that create opportunities for disparate systems to work together.