Figure 6-5 System Information Icon - Siemens 7SR105 Rho User Manual

6.1.1.2 RS485 Interface
The RS485 communication port is located on the rear of the relay and can be connected using a suitable RS485
120 ohm screened twisted pair cable.
The RS485 electrical connection can be used in a single or multi-drop configuration. The RS485 master must
support and use the Auto Device Enable (ADE) feature. The last device in the connection must be terminated
correctly in accordance with the master device driving the connection. The relays are fitted with an internal
terminating resistor which can be connected between A and B by fitting an external wire loop between terminals
X2: TERM and X2: B terminals.
The maximum number of relays that can be connected to the bus is 64.
The following settings must be configured via the relay fascia when using the RS485 interface. The shaded
settings are only visible when DNP3.0 is selected.
Setting name Range
0 ... 254
(IEC60870-5-103)
Station Address
0 ... 247 (MODBUS)
0 ... 65534 (DNP3)
OFF, IEC60870-5-103,
COM1-RS485
MODBUS-RTU, DNP3.0
Protocol
75 110 150 300 600 1200
COM1-RS485 Baud
2400 4800 9600 19200
Rate
38400
COM1-RS485 Parity NONE, ODD, EVEN
COM1-RS485 Mode Local, Remote, Local Or
Remote
©2018 Siemens Protection Devices
Figure 6-5 System Information Icon
Default
0
IEC60870-5-103
19200
EVEN
Remote
7SR105 Rho Description of Operation
Setting Notes
An address must be
given to identify the
1...
relay. Each relay must
have a unique address.
Sets the protocol used
As Required
to communicate on the
RS485 connection.
The baud rate set on all
of the relays connected
to the same RS485 bus
As Required
must be the same as
the one set on the
master device.
The parity set on all of
the relays connected to
the same RS485 bus
As Required
must be the same and
in accordance with the
master device.
Remote Selects whether the
port is Local or Remote.
Chapter 1 Page 51 of 57