The End of an Era for Automation: How Siemens SIMATIC S5 Transformed Manufacturing

Siemens SIMATIC S5, a cornerstone of industrial automation, has officially reached the end of its lifecycle. Since its introduction over 40 years ago, this groundbreaking programmable logic controller (PLC) has revolutionized manufacturing, optimizing countless machines and processes across various industries.

The End of an Era for Automation: How Siemens SIMATIC S5 Transformed Manufacturing

A Technological Leap in Automation

The SIMATIC S5 provided factory engineers with an unprecedented increase in computing power. Its advanced control functions enabled higher-level tasks, while its robust and straightforward technical design ensured long-term reliability. These features contributed to its widespread adoption, from small manufacturers to large-scale production facilities like Heinz’s plant in Wigan.

Despite its longevity, Siemens officially ended the product’s lifecycle on September 30, marking a shift toward the next generation of Siemens automation technologies. This transition has evoked nostalgia among many engineers who recall the significant impact S5 had on industrial automation.

Overcoming Initial Challenges

Alan Norbury, Chief Technology Officer at Siemens Plc., was an apprentice at Siemens when the S5 was introduced. He remembers the challenge of transitioning engineers from traditional relay-based control systems to software-driven automation.

“In the late 1970s, engineers were accustomed to wiring diagrams and relay panels,” Norbury recalls. “The S5 represented a significant shift—it was smaller, more powerful, and controlled by stored programs rather than hard-wired circuits. The real challenge was overcoming the psychological barrier and helping engineers embrace this new way of thinking.”

Siemens designed the S5 to resemble familiar relay panels, easing the transition. Over time, engineers began to appreciate the advantages of stored programming, structured diagnostics, and modularity, which significantly improved troubleshooting and system scalability.

Evolution and Industry Applications

The S5 series was available in multiple chassis styles, including 90U, 95U, 101U/R, 100U, 105R, 110A/S/F, 130A/W, 150S, 115U/F/H, 135U, and 155U/H, with increasingly sophisticated capabilities. Some models supported redundant CPU operation for high-reliability industries like pharmaceuticals, while others offered failsafe features essential for oil and gas applications.

The success of the S5 was further enhanced by the introduction of STEP 5 engineering software. According to Norbury, “Structured programming revolutionized fault diagnosis, making it easier to track errors and optimize processes. This significantly reduced machine downtime, which was particularly beneficial for industries like automotive manufacturing.”

A Market Leader in PLC Technology

Siemens continued to refine the S5 series, introducing the universally applicable S5 U series, which drove rapid sales growth. Key advancements included modularity, improved timing and counting capabilities, and enhanced communication features. These improvements allowed seamless integration with external devices such as printers and monitors, enabling graphical programming and more complex control engineering.

The introduction of the S5-100U range further improved processing speeds and reduced switching times, enabling more advanced manufacturing processes. With safety becoming an increasing priority, Siemens developed the S5-115F, a failsafe controller designed to enhance plant and operator safety.

Legacy and Transition to Modern Automation

Dave Pickles, Managing Director of industrial systems integrator Capula, witnessed firsthand the transformative impact of the S5. “Replacing large, failure-prone control panels with compact, programmable units was a game-changer. It was incredible to see experienced engineers embrace this new technology and recognize its potential.”

One of the defining aspects of the S5’s success was its affordability. “The S5-100U was the first micro PLC available for under £100, making powerful automation accessible to small and medium-sized manufacturers,” Pickles noted. “This democratization of automation leveled the playing field and allowed more businesses to compete on efficiency and innovation.”

Despite the emergence of newer technologies, many S5 units remain operational today. Pickles commented, “Even decades later, I still come across S5 systems in industrial settings, a testament to their durability and reliability.”

After 16 years of continuous innovation, the SIMATIC S5 paved the way for its successor, the SIMATIC S7, introduced in 1994. The S7 marked a new era in industrial automation with enhanced power, speed, flexibility, and networked communications. Further advancements followed with Totally Integrated Automation (TIA) in 1996 and the SIMATIC S7-1200 and S7-1500 controllers in later years.

Looking to the Future

The retirement of the SIMATIC S5 signifies not just the end of a product but the progression of automation into new frontiers. As Norbury reflects, “Automation has evolved from relays and contactors to software, virtualization, and now artificial intelligence. The future lies in AI-driven production, where robots can autonomously solve tasks and factories continuously optimize themselves.”

For over 60 years, Siemens has led the way in automation technology, and with continuous advancements in AI, connectivity, and smart manufacturing, it is poised to shape industrial production for decades to come.