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Field Bus Communication
PROFIBUS
The plugs 750-960, 750-970 offered by WAGO provide the possibility that
arriving and departing data cables can be directly connected to the plug. In
this manner drop cables are avoided and the bus plug can be connected to or
disconnected from the bus at any time without interrupting the data traffic. A
cut-in type bus connection is integrated in these plugs. Due to the capacitive
load of the subscribers and the resulting generated line reflection the
connection plugs used should have integrated length inductivity. This is
indispensable for transmission rates of > 1.5 MBaud.
9 pole D-SUB
Connector
Fig. 4-1: Bus connection
Note
When connecting the subscriber ensure that the data lines are not mixed up.
The bus termination at the start and end of the bus line must be installed. The
bus connection requires the supply voltage VP from the device. For this
reason ensure that the slave unit installed on the bus termination, is always
supplied with voltage.
Due to the integrated length inductivity in the connection plug ensure that the
plug is installed without connected field devices as the missing capacity of
the device could cause transmission faults.
In order to achieve a high disturbance resistance of the system against
electromagnetic radiated interference ensure that a screened PROFIBUS cable
is used. Where possible connect the screen at both ends with good conduction
and using large surface area screen clips. In addition ensure that the cables are
laid separated from all power line cables if possible. With a data rate of
≥ 1.5 Mbit/s ensure that spur lines are avoided.
Further
Fieldbus Nodes
6
2
RxD/TxD-P
3
RTS
4
1
9
RxD/TxD-N
8
7
5
Series inductance = 110 nH
Pin 3 - B Line
Pin 8 - A Line
9 pole D-SUB
Connector with
Terminating Resistor
VP
6
2
RxD/TxD-P
3
RTS
4
1
9
RxD/TxD-N
8
7
DGND
5
WAGO-I/O-SYSTEM 750
Bus System
g1xx302e
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