SERCOS Safety -- The Safety Protocol for SERCOS interface

The SERCOS safety concept, which allows a safe data transfer based on SERCOS interface, was approved by TÜV Rheinland in December 2005 and can now be implemented in SERCOS devices. TÜV Rheinland is an international technical service provider that evaluates, tests and certifies the safety and quality of products. 

SERCOS safety is a protocol extension that is compatible with the established transmission mechanisms of the SERCOS interface. Thus, the SERCOS interface can be used within safety applications up to SIL 3 (Safety Integrity Level) according to IEC61508, even with the shortest cycle times. 

Independent of the type of data -- command values, logical signals or safe logic or process information -- the SERCOS interface provides a homogeneous, continuous solution for modern automation concepts. 

SERCOS safety is independent of the transport layer, so that any transmission physics can be used. Thus, the extension is available both for SERCOS II and SERCOS III and also for other transmission physics, as no special requirements for transmission components need to be fulfilled. Due to the routing capability of the protocol, a safety network may even be extended over several subordinate SERCOS networks. The safe data container, which is embedded in the SERCOS III data telegram, may transfer up to 64 bits of safe user data.

SERCOS safety achieves its best performance when used in combination with SERCOS III. Safe data can be exchanged between slaves directly using the peer-to-peer cross-communication capabilities of SERCOS III, without collection and re-distribution of data by a central master (safety control).

The SERCOS safety specification is available on request.

Specification for SERCOS Controller-to-Controller Profile Released

At the Hannover Fair 2006, the SERCOS trade organizations announced the release of the specification for the Controller-to-Controller (C2C) Synchronization and Communication Profile, a profile for interconnecting motion controllers using the new SERCOS III Industrial Ethernet-based standard for motion control. 

The profile defines mechanisms to interconnect distributed control functions and to synchronize distributed motion controls in modular machines and systems via the SERCOS III interface. The specification takes into consideration innovative SERCOS III features, such as hardware redundancy, hot-plugging and cross communication.

This effort addresses the increasing need in manufacturing systems engineering in which individual machine modules not only need to be connected mechanically, but also need to be integrated into communication networks and coupled in hard real-time. Typical applications for this profile are in printing, packaging and processing machines; as well as machine tools with special requirements for control systems and synchronization, e.g., machine concepts with gantry axes or rotary transfer tables. 

Manufacturer-specific solutions -- based on available SERCOS interface physics -- presently exist for synchronization between distributed motion controls. With the C2C profile, this type of communication has now been standardized.

The C2C specification is available on request.

SERCOS I/O Profile in Progress

As reported in the last SERCOS news, the SERCOS I/O Technical Working Group is preparing a specification for an extended device profile for I/O, based on the existing SERCOS communication protocol. The specification is expected to be released by the end of June 2006.