Installing/Mounting
4.4 Connecting a CU240S DP or CU240S DP-F via PROFIBUS DP
Control Units CU240S
Operating Instructions, 07/2008 - FW 3.2, A5E00766042B AD
39
PROFIBUS terminator
Each bus segment must have a resistor network at both ends as shown in the figure below.
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RII
5
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Figure 4-4
PROFIBUS network with bus termination
The bus termination resistor has to be activated via the terminator switch on the
recommended PROFIBUS connector
The switches of the bus terminator provides both the 220 Ω termination and the 390 Ω
biasing. The 390 Ω biasing maintains the potential difference between the signals in the
PROFIBUS network cables.
WARNING
It must be ensured that any node, where the biasing components of the bus are connected,
is powered at all times in which the bus is in operation.
Removing a bus connector
You can remove the bus connector with looped-through bus cable from the PROFIBUS DP
interface at any time without interrupting the data exchange on the bus. Only the final node
must be terminated.
