PROFINET

PROFINET is an open, Ethernet-based standard for industrial automation communications. It enables real-time data exchange between controllers, sensors, actuators, and other devices over standard Ethernet networks. Developed by PROFIBUS & PROFINET International (PI), PROFINET combines the openness of Ethernet with the determinism required for factory and process automation.

PROFINET defines three main use categories: PROFINET IO for cyclic input/output data between PLCs (IO-Controllers) and field devices (IO-Devices); PROFINET CBA for deterministic data exchange in distributed control applications; and safety over PROFINET (PROFIsafe), which provides safe communication over PROFINET networks to meet safety requirements. The ecosystem is supported by device descriptions in GSDML format to simplify configuration and interoperability.

Real-time behavior is achieved with two primary real-time variants: RT (Real Time) and IRT (Isochronous Real Time). RT handles deterministic cyclic data suitable for most automation tasks, while IRT adds time-critical isochronous synchronization for motion control. Data exchange separates cyclic IO data from explicit data used for configuration, diagnostics, and alarms. Time synchronization relies on IEEE 1588 Precision Time Protocol (PTP), and network redundancy can be provided through methods such as PRP or MRPR, depending on hardware support.

PROFINET runs on standard Ethernet hardware—switches, cables, and network interface cards—and uses GSDML files for device description and automatic configuration. It is standardized within IEC 61158 and IEC 61784, with PROFINET IO defined in IEC 61784-2, and is maintained by PI. It is widely used in manufacturing, automotive, packaging, and process industries, supported by a broad ecosystem of vendors.