Drives and Controls Magazine
Sercos module carries Ethernet and safety data on one cable
Published:  18 August, 2014

Rexroth has developed a PC plug-in card that simplifies machine automation by carrying Sercos, Ethernet/IP, TCP/IP and safety functions on one Ethernet cable. The Sercans master-module can combine real-time, non-real-time and safety communications on a single cable.

The card allows engineers to combine devices from different manufacturers that support Sercos, EtherNet/IP or TCP/IP. It avoids the need for separate sensor and safety buses.

The card supports dual master operation, allowing Ethernet/IP, TCP/IP and Sercos devices to be operated together without needing any extra hardware. Sercos is said to provide enough bandwidth for the parallel exchange of real-time and non-real-time data.

A Sercans master module with a PCI or PCI Express interface can link up to 128 Sercos participants with each other. Up to four Sercos masters can run on one PC, increasing the number of participants to 512.

Rexroth says that the cross-communications between peripheral devices will increase productivity and shorten cycle times, because it provides fast axis couplings and I/O communications. A wizard simplifies the engineering of the cross-communications.

Rexroth's Sercans module plugs into a PC and allows real-time, non-real-time and safety functions to be carried on the same Ethernet cable

A structured memory interface manages systems and cycles and diagnoses HMI configuration data, motion logic and standard Ethernet data. Even before the master has initiated Sercos III communications, network participants can exchange data via TCP/IP, EtherNet/IP and the S/IP protocol. Sercos also supports hot plugging of participants.

The Ethernet cable transfers safety signals using CIP Safety on Sercos – a protocol defined by Sercos in cooperation with ODVA that is certified to SIL3. Additional wiring for a safety bus is eliminated, because safety signals are transferred along with the real-time data on the Sercos network. For example, the Sercans module allows Rexroth’s SafeLogic compact safety control to monitor more than 400 drives with their certified safety functions via a single Ethernet cable.