ITEM C 1-02, Руководство по эксплуатации продукта

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Technology modules
Page 150
12.1.4 Termination and bus terminating resistors
Every bus segment of a PROFIBUS network has to be equipped with bus terminating resistors to minimise line reflections and
to adjust a defined rest potential on the line. The bus termination has to be provided at the beginning and at the end of every
bus segment.
Most PROFIBUS connectors come supplied with integrated terminating resistors. For bus connections with connectors without
integrated terminating resistors, the PROFIBUS-DP interface has its own terminating resistors. They can be activated with the
help of the two DIP switches on the module (switch set to ON).
To ensure safe operation of the network, only one bus termination may be used at a time.
The external connection can also be set up discretely (see
Figure 28
). The power supply of 5 V required for the externally
connected terminating resistors is supplied at the PROFIBUS connector of the PROFIBUS-DP interface (see pin assignment in
Table 47
).
GND 5 V
+5 V
A-Line
B-Line
390 Ohm
220 Ohm
390 Ohm
Figure 28: PROFIBUS-DP interface: Connection with external terminating resistors