Siemens SIPROTEC 6MD665, Manual

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3.2 Checking Connections
113
6MD665 Manual
C53000-G1876-C103-3
• CTS = clear to send
• GND = Signal/Chassis Ground
The cable shield is to be grounded at both line ends. In areas of extremely strong
EMC interferences, the interference immunity factor can be improved by leading the
ground wire in a separate shielded pair of strands. The following tables list the assign-
ments of the D-subminiature connector for the various serial interfaces.
Table 3-6 The assignments of the subminiature socket for the various interfaces
1)
Pin 7 also carries the RTS signal with RS232 level when operated as RS485 interface. Pin 7
must therefore not be connected!
3.2.5 Termination
For bus-capable interfaces a termination is necessary at the bus for each last device,
i.e. termination resistors must be connected for RS485 or PROFIBUS interfaces.
The termination resistors are located on the RS485 and PROFIBUS interface module,
which is located on the CPU processor module.
If the bus is extended, make sure again that only the last device on the bus has the
terminating resistors switched-in, and that all other devices on the bus do not.
3.2.6 Time Synchronization Interface
It is optionally possible to process 5–V–, 12– V– or 24–V–time synchronization sig-
nals, provided that they are carried to the inputs named in the following table.
Pin No. Operator
interface
RS232 RS485 PROFIBUS FMS Slave, RS485
1
2 RxD RxD — —
3 TxD TxD A/A’ (RxD/TxD–N) B/B’ (RxD/TxD–P)
4 — — — CNTR–A (TTL)
5 GND GND C/C’ (GND) C/C’ (GND)
6 — — — +5 V (max. load < 100 mA)
7 — RTS —
1)
—
8 — CTS B/B’ (RxD/TxD–P) A/A’ (RxD/TxD–N)
9 — — — —