Siemens 7XV5655-0BB00 Manual page 12

English
Fig. 4: Connectors and DIP switches / RS485
Fig. 5: Connectors and DIP switch positions FO
12 / 77
RS485 Interface
The bus-capable RS485 interface provides a
more noise-immune link than the RS232
interface. The data transfer rate is identical
for both interfaces. The terminal device (e.g.
SIPROTEC 4 device) to be operated or up
®
to 30 further bus-capable SIPROTEC
devices are connected directly to the RS485
port.
To use the RS485 interface, DIP switch S2-1
must be set to RS485. The position of DIP
switches S1-1+2 depends on whether a
RS485 termination is required or not (the
termination is set to ON as the first or last
device on the RS485 bus).
The DIP switch for the FO idle state (S2-2)
must be OFF (idle state = OFF). For RS485
mode, half-duplex mode must be set using
the configuration tool (see p. 40 Modem
Settings)!
FO Interface
The FO interface has a transmitter and
receiver port with an ST connector. It is a
noise-immune link and is used whenever
especially high interference levels are to be
expected in the operating environment or
when equipotential bonding with the
terminal device has to be avoided. The data
transfer rate is that of the RS232 interface.
The terminal device (e.g. a SIPROTEC
unit) or a further device from the Siemens
accessory program (e.g. 7XV5300 or
7XV5450 star coupler for operating two or
more SIPROTEC
®
connected directly to the FO port.
Note: The FO interface is always active
with the RS232 interface; the DIP switch
(FO-OFF/FO-ON) only sets the idle state.
C53000-G1176-C175-2
7XV5655-0BB00
®
devices) can be
4
®