Checking The Connections - Siemens siprotec 7SA522 User Manual

Installation and Commissioning
8.2

Checking the Connections

8.2.1 Data Connections
PC Operating Inter-
face at Front
System (SCADA)
Interface
8-20
The following tables list the pin-assignments for the various serial interfaces of the de-
vice and the time synchronization interface.
When the recommended communication cable is used, correct connection between
®
the SIPROTEC device and the PC is automatically ensured. See the Appendix, Sub-
section A.1.3 for an ordering description of the cable.
When a serial interface of the device is connected to a central substation control sys-
tem, the data connection must be checked. A visual check of the transmit channel and
the receive channel is important. Each connection is dedicated to one transmission di-
rection. The data output of one device must be connected to the data input of the other
device, and vice versa.
The data cable connections are designated in sympathy with DIN 66020 and ISO
2110 (see also Table 8-8):
− TxD
data transmit
− RxD
data receive
− RTS
request to send
− CTS
clear to send
− DGND
signal/chassis ground
The cable shield is to be grounded at only one end so that potential differences cannot
cause circulating currents to flow along the shield.
The physical arrangement of the connectors is illustrated in Sub-section 2.1.5, Figure
2-15.
Table 8-8 Installation of the D-subminiature ports
Pin No. Operating
interface
1
2 RxD
3 TxD
4 –
5 DGND
6 –
7 RTS
8 CTS
9 –
*) Pin 7 also may carry the RS232 RTS signal to an RS485 interface. Pin 7 must therefore
not be connected!
RS232 RS485
Shield (with shield ends electrically connected)
RxD –
TxD A/A' (RxD/TxD–N)
– –
DGND C/C' (DGND)
– –
RTS –*)
CTS B/B' (RxD/TxD–P)
– –
Profibus FMS Slave, RS485
–
B/B' (RxD/TxD–P)
CNTR–A (TTL)
C/C' (DGND)
+5 V (max. load 100 mA)
–
A/A' (RxD/TxD–N)
–
7SA522 Manual
C53000-G1176-C119-2