Table of Contents
Advertisement
Mounting and Commissioning
3.2 Checking Connections
System interface
For versions equipped with a serial interface to a control center, the user must check the data connection. The
visual check of the assignment of the transmission and reception channels is of particular importance. With
RS232 and fibre optic interfaces, each connection is dedicated to one transmission direction. Therefore the
output of one device must be connected to the input of the other device and vice versa.
With data cables, the connections are designated according to DIN 66020 and ISO 2110:
• TxD = Data Transmit
• RxD = Data Receive
• RTS = Request to Send
• CTS = Clear to Send
• GND = Signal / Chassis Ground
The cable shield is to be earthed at both line ends. For extremely EMC-prone environments, the earth may be
connected via a separate individually shielded wire pair to improve immunity to interference.
Table 3-20
The assignments of the D-subminiature and RJ45 connector for the various interfaces
Pin No.
Operator in-
terface
1
2
RxD
3
TxD
4
-
5
GND
6
-
7
RTS
8
CTS
9
-
1)
Pin 7 also carries the RTS signal with RS232 level when operated as RS485 Interface. Pin 7 must therefore not be con-
nected!
RS485 Termination
The RS485 interface is capable of half-duplex service with the signals A/A' and B/B' with a common relative
potential C/C' (GND). It is necessary to check that the terminating resistors are connected to the bus only at
the last unit, and not at other devices on the bus. The jumpers for the terminating resistors are on the interface
module (see Figure3-12 or Figure 3-13) or directly on the C-CPU-2 (see Figure 3-5 and Table 3-7). Terminating
resistors can also be implemented outside the device (e.g. in the plug connectors) as shown in Figure 3-6. In
this case, the terminating resistors located on the module must be disabled.
If the bus is extended, make sure again that only terminating resistors at the last device to the bus are switched
in.
208
RS232
RS485
Shield (with shield ends electrically connected)
RxD
-
TxD
A/A' (RxD/TxD-N)
-
-
GND
C/C' (GND)
-
-
1)
RTS
-
CTS
B/B' (RxD/TxD-P)
-
-
PROFIBUS FMS Slave, RS485 DNP3.0 RS485
PROFIBUS DP Slave, RS485
-
B/B' (RxD/TxD-P)
CNTR-A (TTL)
C/C' (GND)
+5 V (max. load 100 mA)
-
A/A' (RxD/TxD-N)
-
C53000-G1176-C159-3, Release date 05.2009
Ethernet
EN100
Tx+
-
Tx-
A
Rx+
RTS (TTL level)
-
GND1
-
VCC1
Rx-
-
-
B
-
-
Disabled
SIPROTEC, 7VK61, Manual
Advertisement
Table of Contents
