Sercos III is on the chips - and distributed control is on the way
The first chips to support the Ethernet-based version of the Sercos interface were launched at the recent Hannover Fair. At the same time, the Sercos organisation announced plans for a new profile to support distributed control functions in modular machines and systems.
The Sercos community has been working on Sercos III since October 2003 and the specification was submitted to the IEC for approval late last year. Sercos III uses the same real-time mechanisms of the original Sercos interface, based on cyclic data transfer with deterministic timing. It allows standard IP telegrams (such as TCP/IP) to be transmitted in non-real-time slots in parallel with the real-time processing.
Now, Sercos III has been implemented on a chip (above) developed by Xilinx, which incorporates hardware functions such as timing, synchronisation and processing of cyclic and non-cyclic data. The availability of these chips should make it relatively cheap and easy for manufacturers to add Sercos III support to their equipment.
The Sercos community has also formed a technical working group to draw up a profile that will use Sercos III for distributed control duties. The C2C (controller-to-controller) profile will allow distributed motion controls to be synchronised via the Sercos interface. Although some manufacturers have already developed proprietary communications of this type, the new profile will standardise these links as a supplement to existing device profiles for servo drives and remote I/O.
The work is intended to converge with the ODVA`s CIP Motion Profile and a Sercos-CIP gateway is planned. The C2C profile should be available by next year`s Hannover Fair.