3.2 Checking Connections
255
7UM61 Manual
C53000-G1176-C127-3
3.2
Checking Connections
3.2.1
Checking Data Connections of Serial Interfaces
Pin assignments
The following tables illustrate the pin assignment of the various serial device interfaces
and of the time synchronization interface. The position of the connections can be seen
in the following figure.
Figure 3-13
9-pin D-subminiature female connectors
Operator Interface
When the recommended communication cable is used, correct connection between
the SIPROTEC
®
4 device and the PC is automatically ensured. See the Appendix for
an ordering description of the cable.
System Interface
When a serial interface of the device is connected to a central substation control
system, the data connection must be checked. A visual check of the transmit channel
and the receive channel is important. With RS232 and fibre optic interfaces, each con-
nection is dedicated to one transmission direction. 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
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.
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