Since the introduction of programmable logic controllers (PLCS), various automation controllers have migrated to industrial applications, including Programmable Automation Controllers (PAC) and today's Edge Programmable Industrial Controllers (EPIC). Consumers have more choices in terms of cost, footprint, input/output (I/O) density, fieldbus compatibility, communication, programming capabilities, and processing speed, and competition among leading controller vendors is intensifying.
Diversity is often good for the market, but it can also be frustrating for engineers and end users. Choosing a control platform is a long-term investment that comes with associated costs, such as training and support contracts. Policymakers want to get value for money.
But before endorsing the issue, let's look at how the industry has grown. What is the driving force behind the development of different control solutions? How do these trends play out now? How can users invest in automation to ensure success in the future?
Evolution patterns of industrial controllers
Looking at the advances in automation over the past few decades, it is clear how iterations of specific technologies have driven the development of new I/O and control capabilities.
For example, during the development of the first I/O system, field control and sensing equipment also relied on electromagnetic and pneumatic components, which were limited by physical properties and their service life was compromised. Compact low-voltage components, such as solid-state relays, are driving users to demand more options to integrate I/O directly into their systems. This led to the emergence of the first modular I/O, at the same time as 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 was the first serially addressable I/O rack, an alternative to rack-based I/O in PLCS.
From dedicated, independent I/O devices to modular I/O, and then to bus I/O, all embody the reuse concept in industrial control. Next-generation control platforms incorporate embedded I/O processing circuits. The module expanded from 1 I/O channel to 32 channels, and now I/O is built into PLC and other monomer devices. In some cases, with proper configuration, each I/O channel can accept a variety of different signal types.
This model demonstrates how innovation spreads across an industry: individual innovations become modular over time, collaborating with other technologies and then embedded in those technologies as part of a new innovation cycle.
For PLC and PAC, this mode provides smaller controllers and I/O modules. As the math and programming processor functions are integrated directly into the control board and other devices (such as I/O, transmitters, and network gateways), more computing power is achieved "per square inch". Over time, the same pattern is reflected in the migration of new embedded communication interfaces and protocol standards to controllers.
The convergence of different technologies
The trend of mutual integration and integration cycle intertwined, industrial control market outside the technical innovation, also gradually into the controller. The history of bus I/O shows how this trend has led to the development of new controller capabilities.
From serial bus I/O, there are parallel I/O buses and other solutions that enable minis and microcomputers to interact with I/O. This also inspired the idea of developing a standalone I/O communication processor that separates the I/O from the computer, allowing any computer with a communication port to interact with it.
As I/O modules and processors improved, early hybrid controllers also provided analog signal processing capabilities that were then only available in distributed control systems (DCS). Since ladder logic programs, a PLC programming language, were not originally intended to handle analog data formats, new programming languages for hybrid controllers have been created.
Then low-cost alternatives to the IBM PC began flooding the market. Since the PC is the primary control function in hybrid systems, reliability concerns arise. It was significant that vendors developed an industry-enhanced alternative that integrated the I/O, networking, and programming components of the earlier hybrid solution into one system, which became the PAC system. Pacs use the same processors as PCS and can provide a feature set that fills a niche between low-cost, PLC-based discrete control and high-cost, DCS-based process control.
Innovation in high-tech enterprises and the personal computer market has brought opportunities for the development of industrial control. This trend is accelerating as the fields of operational technology (OT) and information technology (IT) become more and more integrated. Take, for example, the wave of mobile solutions that has emerged in recent years. It is also reflected in the push for big data, cloud analytics and machine learning support, technologies born outside the field of industrial automation.
Future-oriented controllers
As deeper technology integration, greater convergence between industries, and the trend toward greater connectivity between devices and systems continue, what will controllers of the future bring us?
How should engineers choose to ensure that they are in tune with technology and help the organization get the most out of it? The following three suggestions will help manufacturers choose the right control technology to achieve their goals.
1. Focus on design, not functionality
Understanding that technology will continue to improve and become more tightly integrated and embedded over time makes it necessary to prioritize investments in control systems that cannot be easily or quickly changed. Engineers need to focus on the architecture of the control system, rather than the eye-catching features of the day.
2. Look for external innovation
If engineers design systems that evolve over time to keep pace with digital transformation and reduce maintenance and rework, that will impress end users, who will remember that the technologies that determine the future often come from outside the industry.
3 Keep an open mind
The battle for market share in proprietary technologies stifles innovation, while supporting open standards opens up unlimited possibilities for everyone. Connectivity is one of the target metrics for Industry 4.0, and as connectivity increases, engineers need to invest in technologies that can create opportunities for different systems to work together.