![ABB REF615 ANSI 5.0 FP1 Скачать руководство пользователя страница 31](http://html.mh-extra.com/html/abb/ref615-ansi-5-0-fp1/ref615-ansi-5-0-fp1_product-manual_4777031.webp)
—
Figure 15. Parallel
redundancy proto-
col (PRP) solution
HSR applies the PRP principle of parallel operation
to a single ring. For each message sent, the node
sends two frames, one through each port. Both the
frames circulate in opposite directions over the
ring. Every node forwards the frames it receives
from one port to another to reach the next node.
When the originating sender node receives the
frame it sent, the sender node discards the frame
to avoid loops. The HSR ring with 615 series relays
supports the connection of up to 30 relays. If more
than 30 relays are to be connected, it is recom-
mended to split the network into several rings to
guarantee the performance for real-time applica-
tions.
Ethernet switch
IEC 61850 PRP
Ethernet switch
REF615
REF620
RET620
REM620
REF615
SCADA
COM600
31