ETHERNET Powerlink (www.ethernet-powerlink.org/) is an open network protocol extended from standard Ethernet to offer real-time deterministic bus access for distributed automation systems, such as drive control systems. ETHERNET Powerlink (EPL) is suitable for applications with hard real-time requirements in the range of microseconds, or guaranteed transmission of larger quantities of data within a defined period of time. EPL features producer-consumer services that allow users to simultaneously control, configure and collect data from intelligent devices over a single network or use a single network as a backbone for multiple distributed networks.

EPL is patent-free technology developed by the ETHERNET Powerlink Standardization Group (EPSG), which has more than 50 members and more than 80,000 V1 nodes installed worldwide.

EPL supports full compliance with Fast Ethernet (maximum 100 Mbps transmission rate), is compatible with Gigabit Ethernet, standard Ethernet controllers, and Internet Protocol (IP) based protocols (TCP, UDP, and others). It offers hard real-time communication features such as:

• Cycle times as low as 200 microseconds
• Jitter below one microsecond
• Central bus arbitration in the managed node (MN) and collision avoidance on the Ethernet to optimize Ethernet bus capacity utilization
• Up to 1.5 kilobytes of process data per message, with a maximum message rate approximately 100,000 messages per second

The application interface of ETHERNET Powerlink version 2 (V2 completed in 2003) is based on the mechanisms defined in the CANopen communication profile DS301 of Controller Area Network (CAN) in Automation (or EN50325-4). This supports easy migration and integration from/with CANopen. CANopen Mechanisms such as PDO, SDO, OBD and NMT are fully transferred to EPL to ensure interoperability between CANopen and EPL systems and ease migration from CANopen to ETHERNET Powerlink at the software level. This offers customers potential for more technology sources and more vendor-independent system design.