Figure 1. Traditional PLCs and classic ladder — like the AutomationDirect Productivity family using classic ladder logic programming — still play an important role and have gained many modern capabilities, even though their development environment is dedicated. (Image: AutomationDirect)

Industrial automation has traditionally been characterized by proprietary technologies and vendor-specific solutions. However, recent trends are shifting toward greater openness in both hardware and software, reflecting the evolving needs of end users, systems integrators (SIs), and original equipment manufacturers (OEMs).

Initially, industrial automation relied on hardwired systems, such as relays and switches. As automation evolved, programmable logic controllers (PLCs) emerged, which used specialized programming methods, typically ladder logic. These PLCs and their integrated development environments (IDEs) were proprietary, leading to vendor lock-in (Figure 1). The control and software environments were tightly controlled by suppliers, which ensured reliability, but limited flexibility and interoperability.

While this model worked well enough for many years, the industrial sector has become increasingly complex, with a greater need for customization, data handling, and analytics. This has driven a demand for more open and flexible programming solutions. Industrial applications now often require advanced data processing and integration with modern IT-based systems, so traditional methodologies are sometimes inadequate. There have been several developments leading to more open automation:

IEC 61131 Standards: Introduced in the mid-1990s, the IEC 61131 standard was a significant step towards standardizing industrial programming languages. It includes ladder diagram (LD), function block diagram (FBD), structured text (ST), and sequential function chart (SFC). While these languages provide a common framework, they do not fully address cross-vendor code portability issues.

CODESYS IDE: To address the need for portability and improve ease of use, CODESYS was developed. CODESYS is based on IEC 61131-3 and offers a hardware-agnostic IDE that supports multiple platforms. This environment allows developers to write code once and deploy it across various hardware systems. It facilitates code reuse and reduces the learning curve for users, though it may have limitations in accessing certain hardware-specific features.

Open Microcontrollers: The advent of microcontroller platforms like Arduino and Raspberry Pi has introduced modern programming languages, such as C++ and CircuitPython, to industrial applications. These languages, which are more familiar to newer generations of engineers, excel in handling complex mathematical operations and data-intensive tasks. Although these microcontrollers may not replace PLCs entirely, they offer additional options for integrating with existing systems and enhancing data connectivity.

While the shift toward open languages and platforms offers numerous benefits, including reduced licensing costs and increased flexibility, traditional PLCs with proprietary IDEs continue to be used extensively for real-time control tasks where reliability and deterministic behavior are paramount.

Figure 2. AutomationDirect provides many automation choices, including traditional PLCs, a PLC compatible with CODESYS, and the ProductivityOpen family, which leverages Arduino-compatible processors so users can program their automation applications using more modern languages, such as C++ and CircuitPython. (Image: AutomationDirect)

The industrial automation landscape is increasingly diverse. Some applications benefit from the robust capabilities of PLCs, while others leverage modern, open technologies for higher-level processing and integration. In many cases, a hybrid approach is used, combining traditional PLCs for core control functions with open platforms for data processing and analytics (Figure 2).

As industrial automation technologies continue to advance, the balance between traditional and open solutions will likely evolve. The emphasis will be on providing versatile platforms that meet varied user needs, fostering an environment where both legacy and modern systems can coexist and complement each other effectively.

This article was written by Tim Ensminger, Product Manager and Matthew Lappin, Technical Product Manager, both at AutomationDirect (Cumming, GA). For more information, visit here  .

Topics:
Board-Level Electronics Computer software and hardware Computer-Aided Engineering (CAE) Electronic Components Electronics & Computers Information Technology Logic Analyzers Manufacturing systems Software Suppliers Supply chain management

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