The HSR topology presented here is a reference system for process bus usage with switches supporting HSR and IEEE 1588 v2. This topology includes an HSR ring with protection relays where IEEE 1588 v2 clock masters are connected to the ring using Ethernet switches. The HSR ring is presented with light blue lines and normal Ethernet connections with dark blue.
Each connected node in the HSR ring must support the HSR protocol. Single attached nodes can be connected to an HSR ring with a separate redundancy box (RedBox).
Note: Use correct Ethernet ports in the protection relay with HSR. Protection relays with HSR support have three Ethernet ports and redundant Ethernet ports are marked as LAN A and LAN B.
Note: The maximum number of IEDs supported in the HSR ring is 30. This is to keep the ring delay as small as possible for protection applications using the communication channel. When using IEEE 1588 time synchronization and SMV, 15 hops from the clock master to the IED is the maximum to reach 1 μs accuracy in measurements according to the IEEE 1588 v2 standard.
Note: HSR bandwidth is 50 Mbit/s as all messages are doubled for both directions of the ring.