In order to increase the availability of the EtherCAT system and provide for failure scenarios, a second fully redundant Master system can be added to the network via acontis' Master Redundancy feature. This new feature will create an ACTIVE Master and an INACTIVE Backup Master. In normal operation the INACTIVE Backup Master simply forwards frames through and back onto the network using acontis' optimized Ethernet drivers for fast packet forwarding:

Data Synchronization and Inter-Master Communication

By means of fast packet forwarding the ACTIVE Master still receives all the frames in time for the next cycle.
The INACTIVE Backup Master has access to all Process Data. It parses and modifies received frames and adds frames itself after cyclic slave frames. The ACTIVE and INACTIVE Backup Master can communicate with each other using Ethernet-over-EtherCAT (EoE).

Failover

If the ACTIVE Master fails, the INACTIVE Backup Master can takeover and become ACTIVE. Due to the fact that the INACTIVE Backup Master has been connected to the network the whole time, it can control the bus after getting ACTIVE in the case of a failover:

Cable Redundancy with Master Redundancy

Cable Redundancy can be combined with Master Redundancy. The ACTIVE Master communicates directly to one segment of the EtherCAT slave network and indirectly to the other segment of the EtherCAT slave network through the INACTIVE Backup Master: