Installation
• 19
Fieldbus Dependent I/O Module
PROFIBUS DP
The plugs available on the market offer the possibility that arriving and de-
parting 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 con-
nection is integrated in these plugs. Due to the capacitative load of the sub-
scribers and the resulting generated line reflection the connection plugs used
should have integrated length inductivity. This is indispensable for transmis-
sion rates of > 1.5 MBaud.
The width of the plug can be maximum 16 mm.
6
6
3
3
1
1
9
9
8
7
2
2
4
4
7
8
5
5
VP
390
390
220
RxD/TxD-P
RxD/TxD-P
RTS
RTS
RxD/TxD-N
RxD/TxD-N
DGND
9 pole D-SUB
Connector with
Terminating Resistor
9 pole D-SUB
Connector
Further
Fieldbus Nodes
Pin 3 - B Line
Pin 8 - A Line
Series inductance = 110 nH
Fig. 4-15: Cabling and bus termination
g1xx302e
Attention
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 rea-
son ensure that the slave unit installed on the bus termination, is always sup-
plied with voltage.
Due to the integrated series inductance 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.
