Communication protocols define how field devices—sensors, actuators, or robots—exchange data with controllers like PLCs or edge computers. They reduce wiring, save installation time, and lower error risks while enabling smarter, more reliable machines. With protocols, devices share diagnostics, I/O status, and performance data, supporting remote monitoring, AI-driven analytics, cloud services, and new business models that drive efficiency and service innovation.
PLCs first relied on RS232 serial links to connect devices like monitors or printers. In the late 1980s, fieldbus technology replaced complex parallel wiring with digital transmission, later standardized in IEC 61158. Since 1999, diverse fieldbus systems have been widely used, with Ethernet-based, partly real-time protocols forming the next generation. Today, cloud connectivity, data lakes, and IT/OT convergence define modern industrial communication—with security now a core concern.
Information Technology (IT) manages data and applications, such as information systems, office computers, and networks. Operational Technology (OT) monitors and controls physical devices like production equipment. IT/OT convergence integrates both, often via common protocols. However, the technologies differ: Industrial Ethernet must withstand harsher conditions like vibrations, dust, and heat, requiring greater robustness. It’s designed to prevent errors and quickly respond to disruptions, using protocols built for high data rates, collision management, and — most importantly — deterministic communication to ensure data is transmitted on time and production failures are avoided.
But what are the top 10 technologies shaping industrial automation today?
Over 30 protocols were developed in the first generation, but standards like Profibus, Interbus, CANopen, DeviceNet, and CC-Link soon narrowed the field to a few key players.
1. Profibus. Profibus was standardized internationally (e.g., EN 50170) and connected controllers, sensors, and actuators. Variants like Profibus DP and PA served different automation needs. It was one of the most widely used early automation protocols.
2. Interbus. Interbus, an early industry standard, connected devices in a ring topology for fast, reliable data transmission in industrial settings.
3. CANopen and 4. DeviceNet. Both are CAN-based which was originally developed for automotive networking. DeviceNet enabled simple, fast integration, popular in the US, while CANopen offered greater flexibility and advanced management features.
5. CC-Link. CC-Link is a high-speed, real-time open fieldbus widely used and standardized in Asia.
6. Profinet. Profinet is widely used in industrial automation for its high performance, scalability, and Ethernet compatibility. It supports standard TCP/IP, real-time (RT), and isochronous real-time (IRT) data transfer, ideal for complex, time-critical applications. Profinet also enables Industry 4.0 by integrating automation with IT systems, supporting diagnostics, configuration, and maintenance.
7. EtherNet/IP. EtherNet/IP is widely used in industrial automation for its interoperability, scalability, and reliance on standard Ethernet (TCP/IP). Built on the Common Industrial Protocol (CIP), it offers a consistent communication framework for devices like sensors, actuators, and controllers. Supporting both real-time and non-real-time communication, it suits applications from simple control to complex manufacturing.
8. EtherCAT. EtherCAT (Ethernet for Control Automation Technology) is a high-performance, real-time Ethernet fieldbus designed for industrial automation. It processes data on the fly as frames pass through devices, minimizing delays and maximizing efficiency. Known for low latency, precise synchronization, and scalability, EtherCAT is ideal for motion control, robotics, and high-speed manufacturing.
9. Powerlink. Powerlink is an open, real-time Ethernet protocol for industrial automation, offering deterministic, high-speed communication. It uses a time-scheduled, master-slave mechanism to ensure precise data exchange with low latency and jitter, ideal for tasks like motion control and robotics.
10. CC-Link IE. CC-Link IE is an open, high-speed Ethernet-based fieldbus developed by the CC-Link Partner Association. It offers gigabit speeds and real-time, deterministic communication for industrial automation. Widely used in Asia, it enables seamless device integration across complex networks and supports Industry 4.0 applications like smart factories and IIoT.
Beyond the top 10 industrial automation protocols, four key additions stand out.