PROFINET vs. PROFIBUS: Key Differences in Cabling and Applications

By Eileen Harvey 

Industrial automation has rapidly evolved over the past few decades, driven by advancements in technology and the increasing demand for efficiency and productivity in manufacturing processes. Legacy fieldbus systems, such as PROFIBUS, were once the backbone of factory communication, providing a reliable means of connecting devices and facilitating data exchange.  

However, as industries embrace the principles of Industry 4.0 characterized by smart manufacturing, interconnected systems and real-time data analytics, PROFINET has emerged as the leading networking standard. This evolution is not merely a shift in technology; it's a response to the need for more flexible, scalable and high-performance communication solutions that can support the dynamic environments of modern production lines. 

PROFIBUS, with its legacy infrastructure and robustness, may still be applicable for certain applications where simplicity and cost-effectiveness are paramount. In contrast, PROFINET, with its ability to handle large volumes of data at high speeds and support for real-time communication, is better suited for complex automation systems that require integrated control and monitoring. 

What is PROFIBUS? 

PROFIBUS (Process Field Bus) is a fieldbus communication standard introduced in the late 1980s. It uses RS-485 twisted pair cabling to enable communication between controllers and field devices such as sensors, actuators and drives. Its cable structure is typically two-wire shielded twisted pair. Standard impedance is 150 ohms. It supports up to 12 Mbps, but real-world speeds are often lower. 

PROFIBUS is widely used in process industries such as oil and gas, chemical and power generation. It is also used in factory automation lines that were built in the 1990s and 2000s. 

Its limitations are that it has slower speeds compared to Ethernet-based systems and limited bandwidth for data-heavy IIoT applications. It is also difficult to integrate with IT systems. 

What is PROFINET? 

PROFINET is an Ethernet-based communication standard developed for industrial automation. Unlike PROFIBUS, it uses Ethernet cabling (Cat5e, Cat6, Cat7) to deliver real-time data transmission across machines and networks. Its cable structure is four-pair copper cables with shielding (foil, braid or combination). Its standard impedance is 100 ohms and it can achieve 100 Mbps and beyond. 

PROFINET applications include: robotics, packaging and motion control systems; high-speed production lines where real-time communication is critical; and environments that demand scalability and Industry 4.0 integration. 

Cabling Differences: PROFINET vs. PROFIBUS 

Performance Comparison 

When comparing network performance, PROFINET delivers significantly higher data transfer speeds, reaching up to 100 Mbps, while PROFIBUS is limited to a maximum of 12 Mbps. PROFINET also provides greater scalability, supporting integration with IT networks, cloud systems and IoT platforms, which allows for more advanced data management and remote monitoring. In terms of real-time capability, PROFINET offers both RT (Real-Time) and IRT (Isochronous Real-Time) modes, giving it a clear advantage for precise motion control applications. However, PROFIBUS can transmit signals over longer distances without repeaters—up to 1,200 meters—whereas PROFINET typically requires switches or repeaters for runs beyond 100 meters. 

Applications in Industry 

PROFIBUS remains the preferred choice in legacy industrial plants that do not require high data throughput, as well as in process automation environments such as water treatment facilities and oil and gas operations. PROFINET, on the other hand, excels in robotics and packaging machinery, high-speed motion control systems and modern factories implementing IIoT and predictive maintenance strategies. Many facilities now adopt hybrid systems that combine both technologies, using PROFINET–PROFIBUS gateways to integrate older infrastructure with newer automation networks seamlessly. 

Migration from PROFIBUS to PROFINET 

Transitioning from a PROFIBUS system to PROFINET involves several key upgrades to ensure compatibility and performance. The cabling infrastructure must shift from traditional RS-485 twisted-pair wiring to Ethernet-based Cat5e, Cat6 or Cat7 cables. Network hardware such as switches and connectors also needs to be replaced with components designed for industrial Ethernet to handle higher data speeds and real-time communication. Additionally, device firmware must be updated or replaced to support Ethernet-based protocols, enabling seamless communication within the PROFINET environment. 

Tips for Choosing Between PROFINET and PROFIBUS 

When deciding which network technology best suits your operation, consider the system’s performance requirements and long-term goals. If your application demands real-time motion control and precise synchronization, PROFINET is the clear choice. In contrast, legacy plants with stable and lower-speed setups may continue operating efficiently with PROFIBUS. For environments with high electromagnetic interference, shielded PROFINET cables should always be used to maintain signal integrity. Type C PROFINET cables are ideal for robotics applications that involve continuous flexing and movement. Finally, any network planning or upgrades should be made with future Industry 4.0 integration in mind to ensure scalability and long-term compatibility. 

Facts Section 

• Over 56 million PROFIBUS devices are still installed globally. 

• PROFINET adoption is growing by over 20% annually, especially in Europe and Asia. 

• Cable-related failures account for nearly 30% of industrial downtime. 

• TKD Kabel is recognized as a leading brand for industrial-grade cabling, ensuring long-term reliability. 

FAQs About PROFINET vs. PROFIBUS 

Q1: What is the main difference between PROFIBUS and PROFINET cabling? 
A: PROFIBUS uses two-wire RS-485 twisted pair, while PROFINET uses Ethernet Cat 5e/6/7 cabling with higher speeds and shielding. 

Q2: Can I use PROFIBUS and PROFINET together? 
A: Yes. Gateways allow hybrid communication, enabling gradual migration. 

Q3: Is PROFINET backward compatible with PROFIBUS? 
A: Not directly. However, many devices support dual interfaces or can connect through gateways. 

Understanding the key differences between PROFINET and PROFIBUS is essential for anyone navigating the landscape of industrial automation. While both protocols serve vital roles in facilitating communication between devices, their distinct cabling requirements and applications can significantly influence project outcomes. PROFINET’s flexibility and speed make it ideal for modern, data-intensive environments, while PROFIBUS remains a reliable choice for legacy systems and simpler applications.  

Explore the full range of TKD Kabel through L-com. We’ll fill your orders fast, with same-day shipping on all qualified, in stock, online orders received Monday through Friday before 5 p.m. EST. For TKD-related inquiries, connect with our U.S-based TKD expert Eileen Harvey at eharvey@infiniteelectronics.com.