Why the PLC is Better than a Raspberry Pi in Industrial Automation

With the rise of low-cost computing platforms such as the Raspberry Pi, many engineers and hobbyists have explored their potential in automation projects. At first glance, a Raspberry Pi can seem like an attractive option: it is inexpensive, versatile, and supported by a vast open-source community. However, when it comes to industrial automation, the programmable logic controller (PLC) continues to outperform and outlast alternatives such as the Raspberry Pi.

The first and most obvious advantage of a PLC is reliability. PLCs are specifically designed to operate in harsh industrial environments where heat, dust, vibration, and electrical noise are constant factors. Unlike consumer-grade hardware, which can fail when exposed to these conditions, PLCs are built with industrial-grade components that ensure consistent operation, often for decades.

Safety and compliance are another critical area where PLCs hold the advantage. PLCs are developed in line with international standards such as IEC 61131 and IEC 61508, making them suitable for safety-critical applications. They are designed to integrate with certified safety modules, emergency stops, and redundancy systems. A Raspberry Pi, while powerful, does not meet these standards and cannot be relied upon in safety-rated applications.

Another key strength of the PLC is real-time control. Industrial processes require deterministic behaviour: inputs must be read and outputs must be switched at precise, repeatable intervals. PLCs are optimised for this task, ensuring cycle times remain consistent even under high system loads. By contrast, the Raspberry Pi runs on a general-purpose operating system that cannot guarantee the same level of responsiveness, making it unsuitable for critical automation tasks.

From a practical perspective, PLCs also simplify system integration. They support industrial communication protocols such as PROFINET, EtherNet/IP, Modbus, and Profibus directly, ensuring seamless connectivity with drives, HMIs, sensors, and higher-level SCADA or MES systems. While Raspberry Pi can be configured to run some protocols through add-on software and hardware, it requires significant engineering effort and is rarely as robust.

Maintenance is another factor in the PLC’s favour. Engineers across the world are trained to work with PLCs, and spare parts are readily available from established suppliers. The long product lifecycle of PLCs also means that support is guaranteed for many years, often decades. Raspberry Pi boards, in contrast, are not designed with guaranteed supply chains or long-term product support, which can create risks for manufacturers needing consistency across multiple sites and projects.

While Raspberry Pi has value as a learning tool, prototype platform, or for small non-critical tasks, the PLC remains the backbone of industrial automation. Its reliability, compliance with safety standards, deterministic control, and long-term support make it a far better choice for production environments where downtime and failure are not an option.

In conclusion, although Raspberry Pi may have its place in education and experimentation, the PLC is purpose-built for industry. For businesses that depend on safe, reliable and efficient automation, the PLC will always be the superior choice.