PROFINET’s Real-Time Communication

PROFINET seamlessly integrates IT and industrial automation needs through three distinct communication methods:

  1. Standard TCP/IP Communication: Ideal for non-deterministic tasks such as parameterization, audio/video streaming, and data exchange with higher-level IT systems.

  2. Real-Time (RT) Channel in PROFINET: This approach circumvents standard TCP/IP layers to provide deterministic communication, typically within 1-10 ms, making it suitable for automation. It’s a software-centric solution fitting for standard I/O tasks, motion control, and demanding performance scenarios. Notably, this is the mode in which the RT-Labs P-Net Profinet IO device stack operates, ensuring efficient and reliable performance for various applications.

  3. Isochronous Real-Time (IRT) Communication: Focused on high precision and synchronization, especially in motion control tasks, this method achieves cycle times under a millisecond with minimal jitter. It necessitates specialized hardware, usually in the form of ASICs, to function effectively.

  4. Time-Sensitive Networking (TSN): An emerging solution based on relevant IEEE Ethernet standards, currently in development for specific applications.

These communication channels operate concurrently, with bandwidth allocation ensuring that at least half of each I/O cycle is reserved for TCP/IP communications. Paired with durable cabling, connectors, and Ethernet switches, PROFINET addresses a wide range of automation demands.

Significantly, PROFINET adheres to global Ethernet standards, unlike some Industrial Ethernets that deviate from these norms and lack compatibility with conventional office systems. Networks not conforming to these standards often encounter interoperability issues within broader enterprise structures and other fully compliant Industrial Ethernets.