—
Figure 17. Self-healing 
Ethernet ring solution
All communication connectors, except for the front 
port connector, are placed on integrated optional 
communication modules. The relay can be con-
nected to Ethernet-based communication systems 
via the RJ-45 connector (100Base-TX) or the fiber 
optic LC connector (100Base-FX). If connection to
serial bus is required, the 9-pin RS-485 screw-ter-
minal can be used. An optional serial interface is 
available for RS-232 communication.
Modbus implementation supports RTU, ASCII and 
TCP modes. Besides standard Modbus functional-
ity, the relay supports retrieval of time-stamped 
events, changing the active setting group and up-
loading of the latest fault records. If a Modbus TCP 
connection is used, five clients can be connected to 
the relay simultaneously. Further, Modbus serial 
and Modbus TCP can be used in parallel, and if re-
quired both IEC 61850 and Modbus protocols can 
be run simultaneously.
DNP3 supports both serial and TCP modes for con-
nection up to five masters. Changing of the active 
setting and reading fault records are supported. 
DNP serial and DNP TCP can be used in parallel. If 
required, both IEC 61850 and DNP protocols can be
run simultaneously.
When the relay uses the RS-485 bus for the serial
communication, both two- and four wire connec-
resistors can be configured with jumpers on the 
communication card so external resistors are not 
needed.
The relay supports the following time synchroniza-
tion methods with a time-stamping resolution of 1 
ms.
Ethernet-based
• SNTP (Simple Network Time Protocol) 
With special time synchronization wiring
Code Format B)
Managed Ethernet switch
with RSTP support
Managed Ethernet switch
with RSTP support
Client BClient A
Network A
Network B
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