ABB RELION 615 Series Applications Manual page 36

Section 2
REF615 overview
30
In case a laptop or a PC workstation is connected as a non-PRP node to one of the PRP
networks, LAN A or LAN B, it is recommended to use a redundancy box device or an
Ethernet switch with similar functionality between the PRP network and SAN to remove
additional PRP information from the Ethernet frames. In some cases, default PC
workstation adapters are not able to handle the maximum-length Ethernet frames with the
PRP trailer.
There are different alternative ways to connect a laptop or a workstation as SAN to a PRP
network.
• Via an external redundancy box (RedBox) or a switch capable of connecting to PRP
and normal networks
• By connecting the node directly to LAN A or LAN B as SAN
• By connecting the node to the protection relay's interlink port
HSR
HSR applies the PRP principle of parallel operation to a single ring, treating the two
directions as two virtual LANs. For each frame sent, a node, DAN, sends two frames, one
over each port. Both frames circulate in opposite directions over the ring and each node
forwards the frames it receives, from one port to the other. When the originating node
receives a frame sent to itself, it discards that to avoid loops; therefore, no ring protocol is
needed. Individually attached nodes, SANs, such as laptops and printers, must be attached
through a "redundancy box" that acts as a ring element. For example, a 615 or 620 series
protection relay with HSR support can be used as a redundancy box.
GUID-207430A7-3AEC-42B2-BC4D-3083B3225990 V3 EN
Figure 8: HSR solution
1MAC109016-MB C
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Application Manual