Mounting and Commissioning
3.2 Checking Connections
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
439
System Interface
When a serial interface of the device is connected to a control center, the data connection must be checked. A
visual check of the assignment of the transmit and receive channels is important. With RS232 and fiber optic
interfaces, each connection is dedicated to one transmission direction. For that reason the data output of one
device must be connected to the data input of the other device and vice versa.
With data cables, the connections are designated according to DIN 66020 and ISO 2110:
• TxD = Data output
• RxD = Data input
• RTS = Request to send
• CTS = Clear to send
• GND = Signal/Chassis Ground
The cable shield is to be grounded at
both ends
. For extremely EMC-prone environments, the GND may be
connected via a separate individually shielded wire pair to improve immunity to interference.
Table 3-31
Connector Assignment at 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 con-
nected!
Additional Interface (only 7SJ64)
The additional port (Port D), which is only available for device 7SJ64, is used to connect signals from one or
two RTD boxes. The connection according to one of the connection examples given in Appendix A.3 must be
verified. For the assignment of the connectors, see the table above.
Termination
The RS485 interface is bus-capable for half-duplex operation with the signals A/A' and B/B' and the common
reference potential C/C' (GND). Verify that only at the bus of the last device the terminating resistors are con-
nected but not at the bus of the other devices. The jumpers for the terminating resistors are located on the in-
terface module RS485 (see figure 3-20) or the Profibus RS485 (see figure 3-22). With 7SJ64 they are located
directly on the C–CPU-2 (see figure 3-13 and table 3-17). The terminating resistors can also be connected ex-
ternally (e.g. to the connection module, as illustrated in figure 3-14). In this case, the terminating resistors
located on the module must be disconnected.
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.
Pin-
Nr.
RS232
RS485
Profibus FMS Slave, RS485
Modbus RS485
EN 100
electr.
RJ45
IEC 60870–5–103
redundant
RS485 (RJ45)
Profibus DP Slave, RS485
DNP 3.0 RS485
1
Shield (with shield ends electrically connected)
Tx+
B/B’ (RxD/TxD-P)
2
RxD
–
–
–
Tx–
A/A’ (RxD/TxD-N)
3
TxD
A/A’ (RxD/TxD-N)
B/B’ (RxD/TxD-P)
A
Rx+
4
–
–
CNTR-A (TTL)
RTS (TTL Pegel)
–
5
GND
C/C’ (GND)
C/C’ (GND)
GND1
–
6
–
–
+5 V (max. load <100 mA)
VCC1
Rx–
7
RTS
–
–
–
8
CTS
B/B’ (RxD/TxD-P)
A/A’ (RxD/TxD-N)
B
–
9
–
–
–
–
not privided
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