Will Soft PLC Become the Mainstream PLC of the Future?

The concept of Soft PLC has been around for some time. As early as 2020, when we started offering CODESYS-related courses, we were already using Soft PLC. Nowadays, in the field of industrial control, Soft PLC combined with EtherCAT master can replace most domestic application scenarios.

Will Soft PLC replace traditional hard PLC?

Indeed, many industrial control PLC system vendors both domestically and internationally have already launched corresponding Soft PLC products. The following image shows some product lines from automation system manufacturers that adopt the CODESYS Soft PLC solution:

In addition to the manufacturers listed in the image, many domestic and international system vendors, including some that do not primarily focus on PLC product lines, have also adopted Soft PLC to strengthen their competitiveness and solidify their customer base.

Definition of Soft PLC

Soft PLC refers to a control system software architecture where the control logic software is partially or completely decoupled from the PLC hardware, allowing the software to execute control logic workloads on different hardware.It combines the functionalities of traditional PLCs with those of data loggers, communication gateways, and other elements such as Human-Machine Interfaces (HMI) and web servers. Early Soft PLCs typically used industrial PC hardware as a platform, initially running on Windows. Now, most installations use real-time operating systems (Linux, VxWorks, FreeRTOS, QNX, etc.).

Advantages of Soft PLC

Accelerated PLC Market Entry: Converting a circuit board into a PLC (2 days of integration) is as easy as adding a communication protocol. The development of the circuit board and application can proceed in parallel. As promoted by CODESYS in China, the slogan is: “Rapid PLC Development”! Even we can integrate their runtime to develop devices on different hardware platforms into controllers.

Flexibility: With access to source code, changes can be made to the CPU and/or operating system while retaining the application, allowing for targeting multiple markets.Openness: Soft PLC is a simple application module that can work with other applications (motion control, HMI, gateways, business applications, etc.).Standards Compliance: Soft PLC allows the use of five IEC61131 languages, and due to compliance with protocol standards (IEC61850, IEC101/104, DNP3, etc.), the certification process is simplified.Cost-Effectiveness: A single investment is sufficient to create an unlimited number of applications and control the pricing of its products throughout their lifecycle. Additionally, you can invest only in the required protocols.Security: PLC software providers offer security resources and updates to help you comply with the latest market standards, allowing you to focus on your business.Performance: The same logic engine can run on low-performance hardware (e.g., 128 KB RAM) or on powerful servers that can manage up to 500,000 variables.Product Differentiation: In addition to bringing PLC functionality to your products, you can achieve optimal customization by adding features such as HMI, motion control, business applications, gateways, etc.

Soft PLC’s “Innovator’s Dilemma”

Soft PLC represents a disruptive technology that is creating an “innovator’s dilemma” for existing “hard PLC” suppliers. When disruptive technologies emerge, existing companies face the “innovator’s dilemma” of either continuing to improve existing products to serve current/high-end customers or developing new/low-end products using disruptive technologies.

One can look at the historical development of Kodak as a well-known example of a company that went from completely dominating its field to bankruptcy due to digital disruption. In 1976, the company held a 90% market share in global film sales and was also the inventor and patent holder of the world’s first portable digital camera in 1975. However, fearing the erosion of its existing, highly profitable film business, Kodak delayed the development and commercialization of the portable digital camera. This delay opened the door for low-cost Asian competitors, ultimately leading Kodak to file for bankruptcy in 2012.

This historical lesson remains equally relevant today. The struggle between protecting existing businesses to meet current customer needs and embracing new technologies to meet future demands is known as the “innovator’s dilemma” (a concept introduced by Clayton Christensen).

The industrial sector is also not immune to digital disruption and is currently on the brink of a technological revolution. Today, industrial control is primarily managed by PLCs (Programmable Logic Controllers), which are referred to as industrial black boxes. They are hardwired to control time-critical processes such as motor control and valve control, operating based on user-written programs. Almost all manufacturing processes today utilize this technology, provided by industrial automation companies such as Siemens, Rockwell Automation, ABB, and Schneider Electric.

The above image oversimplifies the situation (for example, different types of hard PLCs target both high-end and low-end markets, with at least two categories of soft PLCs), but it captures the essential dynamics of the market, which are similar to the classic “innovator’s dilemma.”

Hard PLCs (a market dominated by existing suppliers) have historically met most of the demands of the existing/high-end market, such as high reliability, fast cycle times, and, most importantly, the support and maintenance capabilities of the existing workforce. On the other hand, Soft PLCs initially met the needs of new/low-end customers by providing more flexible, non-deterministic control solutions, often at a fraction of the cost of similar hard PLCs.

Since entering the market in the 1990s, Soft PLCs have rapidly become more high-performance due to advancements in virtualization technology, real-time Linux operating systems, and more powerful edge computing hardware, thus moving upward along the y-axis in the above chart.

To further support the argument that Soft PLC is indeed a disruptive force in the market, we can look at the success of BECKHOFF (a German supplier utilizing Soft PLC technology) relative to leading “hard PLC” supplier Rockwell Automation.

We can check the market performance of BECKHOFF from 1980 to 2024 on their official website, as shown in the following image:

From the chart, we can see rapid growth in recent years, reaching 1.17 billion euros in 2024, equivalent to 9 billion yuan. Although the total output value is not high, the global employee count is only 5,500 (including about 2,200 engineers), resulting in a per capita output value of nearly 2 million yuan. At least, based on Beckhoff’s growth rate and the increasing trend of domestic manufacturers adopting CODESYS Soft PLC solutions, it appears that Soft PLC will gradually approach the market share of traditional PLCs. Whether it will become mainstream depends on their respective developments, but it is at least a trend. Therefore, in recent years, giants like Rockwell, Schneider, ABB, and Siemens have also begun to introduce Soft PLC products.

Security Issues of Soft PLC

Safety and security of any automation system component is always a primary concern. The safety and security of Soft PLCs have been misunderstood, primarily because early solutions ran on non-deterministic operating systems. Almost all manufacturers have developed robust, safe, and secure solutions using Soft PLC technology.

One advantage of Soft PLC solutions is that they allow for the independent selection of hardware and operating systems based on safety and security requirements.Additionally, some Soft PLC solutions have even developed variants that can be integrated by OEMs into systems designed to achieve IEC61508 (safety) certification. They achieve this by reducing the functional set, removing features that may pose safety risks, and developing runtime using approved methods.Of course, one can also learn from Beckhoff’s Twinsafe safety solution:From independent control to distributed control, including direct preprocessing of data by I/O terminals, to software-based control for highly complex safety applications. Customers can enjoy cost-effective, flexible, and well-scalable solutions, ensuring that all safety requirements are met now and in the future.

Conclusion

For those who have not researched or used Soft PLC solutions in recent years, it is worth revisiting. Many changes have occurred in the 30 years since the introduction of IEC 61131-3, and many popular “traditional” PLCs are actually running Soft PLC technology.

As with any solution choice, future Soft PLC-based solutions should be included in our considerations.

So, as one of the most widely used software brands for Soft PLC, if you haven’t used CODESYS yet or are preparing for future work, hurry up and learn it. The previous video courses are available for everyone to check out, and more suggestions can be left in the comments!

Reference Links:

1. https://www.esa-automation.com/en/advantages-of-softplc-vs-traditional-plc/

2. https://www.esa-automation.com/en/advantages-of-softplc-vs-traditional-plc/

3. https://www.esa-automation.com/en/advantages-of-softplc-vs-traditional-plc/

4. https://straton-plc.com/en/services-and-support/what-is-a-software-plc/

5. https://www.automation.com/en-us/articles/february-2022/what-you-may-not-know-about-softplcs

6. https://iot-analytics.com/software-based-plcs-revisiting-industrial-innovators-dilemma/

7. https://www.beckhoff.com/en-en/products/automation/twinsafe/twinsafe-project-design/

8. https://www.beckhoff.com/en-en/company/

9. https://iot-analytics.com/soft-plc-industrial-innovators-dilemma/

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