New Sercos will join forces with Ethernet

Work has started on a new version of the Sercos motion control interface which will link it with Ethernet to boost its facilities and cut its costs. A progress report on the proposed Sercos-III was issued at the SPS/IPC/Drives show in Nuremberg late last year.

The new version, which is expected to reach the prototype stage next year, is based on the established real-time mechanisms of the original Sercos interface, combined with the universal communications of Ethernet.

It will still work on the principle of cyclic data transfer with an exact time pattern. The developers believe that hardware-based synchronisation is essential for reliably implementing applications such as electronic line shafts in printing machines, packaging machines, and multi-axis machine tools.

Sercos-III will allow standard IP telegrams - such as TCP/IP - to be transmitted in non-real-time time-slots, in parallel to the real-time transfer of the data needed for motion control. The controller will be able to exchange these telegrams with devices higher in the network.

Sercos-III is designed to be as compatible as possible with the established Sercos mechanisms, allowing existing software to be upgraded easily and cheaply.

A key goal is to cut the node costs by offering powerful, low-priced hardware components. Options being examined include an FPGA-based controller and a multi-protocol communications controller.