Advantages of Sercos III

Summary of Sercos

The latest Sercos is the third and thus the newest model of the Sercos Interface Automation bus series, marketed first in 1985. Since then, the Sercos series has developed into a worldwide standard in automation technology, based on good quality as well as low interference susceptibility of the product innovation. In 1995, Sercos Interface was named as worldwide standard for communication for Motion Control. Today, Sercos has more than 3 million installed Sercos nodes in approximately 350,000 applications.

Innovations in the third generation of the Sercos Series

As the newest and most innovative model of the Sercos series, Sercos III is leading the way in real-time communication in the automation technology. Among other factors, the number of new functions and the high efficiency and performance are distinguishing features of the automation bus.
The following gives a short overview of the new developments:

  • Standard Ethernet is currently being used for transfer.
  • Faster operation because of a higher bandwidth
  • Better synchronization by line delay compensation
  • New communication mechanisms and device profiles for versatile application
  • Cross traffic and other innovative opportunities for communication
  • Quick-acting media redundancy guarantees a higher machine availability.
  • Simplified implementation

The Advantages of Sercos III in Detail

Versatile application

  • Any number of automation devices can communicate via one and the same network, which is based on the Ethernet technology for automation technology.
  • The safety technology of the network is not impaired by any participant - no matter whether it is considered as safe or not.
  • Protocol data can be transferred at the same time as real-time data without affecting the data.

Higher Transfer and Operation Speed

  • Sercos III operates with 100 Mbps, which corresponds to the speed of the Fast Ethernet.
  • Short transfer times, because of the extremely efficient and fast processing of the received telegrams, even while passing through the devices. Furthermore, additional network components (like for example switches) can be dispensed with.
  • Any participants can communicate with each other and directly by cross traffic.


  • The multiplexing process uses the bandwidth optimally.
  • Any cycle time for the communication can be selected, and it can vary between 31.25 microseconds and 65 milliseconds.


  • Synchronization can be realized down to the sub-microsecond range.

Consistent Communication

  • Protocols of the office communication can be transferred even during real-time communication of Sercos III without influencing or impairing each other.
  • Redundancy and synchronization can be realized at the same time.
  • Sercos-III-enabled devices can communicate directly by standard Ethernet via MAC or IP addresses, so that a tunnel becomes unnecessary. Examples of such communications are e-mail and Web services. These occur in the Unified Communication Channel (UCC).
  • Diagnosis and start of operation are possible via standardized interfaces.


  • CIP Safety on Sercos guarantees secure communication with Sercos III by routing even beyond the network boundaries. This eliminates an additional safety bus that normally would assume this function. CIP Safety On Sercos transfers the data in the same way as normal standard data, namely on the same medium. With this, the functionality of the safety protocols lies in the terminal devices. This enables simultaneous operation of standard and safety devices in the Sercos Interface network. This safety is guaranteed for all communication levels and channels.

Always available by variable Topology

  • With the ring topology, communication is maintained even in the case of a node failure or a wire break.
  • Sercos III requires only max. 25 microseconds for recognition of a node failure, so that, at worst, the data of the last cycle is lost before data transfer can be continued without impairment.


  • Control can be centralized as well as decentralized.
  • There are no limits for the architecture of the network, as free arrangement of the participants is possible.
  • Ring topology as well as line topology can be used, as well as hierarchical, synchronized networks coupled in real-time.
  • Hot plugging can be used without impairment of the other functions.

Simplified Configuration and Handling

  • Because of consistent device models and device profiles, the Sercos III devices can be put into operation and can be configured to the respective requirements.
  • The protocol can recognize automatically where which device was connected, which facilitates localization of a fault considerably.
  • The connection sequence of the two ports on the device plays no role.

Cost Savings

  • Additional network components are no longer required (for example switches).
  • The master can be implemented as pure hardware, as hardware and software, or as pure software.
  • The slaves are connected via multi-protocol chips.


  • Sercos III is recognized as the international standard for real-time communication and is standardized as real-time Ethernet protocol Sercos III.

Manufacturer-independent technology

  • All specifications are freely accessible.
  • A membership is not mandatory for use of the Sercos III technology.

Future-oriented technology

  • Sercos products are international standard.
  • The technology is being continuously improved and developed further so as to be able to react to the changed market requirements.
  • Backward compatibility offers a more secure return on investment than conventional products.

Proven on the market through quality

  • Sercos innovations are used in widely differing areas of the automation industry, especially for demanding processes.
  • Sercos products are used and supported worldwide by leading automation manufacturers.