ETHERNET FOR ISOCHRONOUS, REAL-TIME COMMUNICATION

In recent years the trend in industrial automation has seen high performance networking of distributed drives and motion controllers becoming much more common. Technologies from the IT world are being increasingly used in industrial automation applications, one such standard is Ethernet.

Some complex industrial automation tasks require hard real-time. However, conventional fast Ethernet switches are not capable of delivering data fast enough for motion control applications.

Combine isochronous real-time and IT data without compromise

NEC Electronics’ new ERTEC devices give the opportunity to have one Ethernet Switch to handle all the Ethernet traffic both conventional and real-time.

In order to cover the requirements of automation to their full extent, the PROFINET standard specifies real-time features at two levels, Real-time (RT) and Isochronous Real Time (IRT).

Using standard Ethernet switches RT performance can be obtained but to get reaction times well below 1 millisecond IRT must be running and this is where the ERTEC devices come into their own.

click to enlarge ...

ERTEC the ENHANCED REAL-TIME ETHERNET CONTROLLER

To be able to take advantage of PROFINET with IRT running NEC Electronics offer two new devices, called the ERTEC 200, which is a 2 port switch with integrated PHY, and the ERTEC 400, a 4 port switch with Reduced Media Independent Interface (RMII) and PCI interfaces.

These devices can far outperform standard Ethernet switches and guarantee data throughput for hard real-time critical motion control devices and still leave 50% of the bandwidth for IT communication. The performance matrix for the ERTEC real-time switches allows for up to 150 control nodes at a cycle time of 1 millisec, with 6 MB/sec of simultaneously transferable TCP/IP data.

Based on the IEEE 802.3 transmission standard, the ERTEC hardware is designed to work with the PROFINET Real Time protocol. The ERTEC hardware also supports the time stamping for IEEE 1588.