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CHAPTER 3
WIRING, CONNECTING
3.1 Physical interface
Isolation: The bus is galvanically separated from the other electronics with an on board DC/DC converter. Bus
signals (A-line and B-line) are isolated via photo couplers.
Profibus-DP communication ASIC:
Bus connection: The SJ-PB2 connects to the Profibus network with a 9-pin female DSUB connector. For the pin
layout, refer to Table 3-1.
Pin
Name
Housing
Shield
1
Not Connected
2
Not Connected
3
B-Line
4
RTS
5
GND BUS
6
+5V BUS
7
Not Connected
8
A-Line
9
Not Connected
(note 1) +5V BUS and GND BUS are used for bus termination. Some devices, like optical transceivers (RS485
to fiber optics) might require external power supply from these pins. RTS is used in some equipment to
determine the direction of transmission. In standard applications only A-Line, B-Line and Shield are used.
The SJ-PBT2 connects to the Profibus network with a 6-poles 2pieces connector. For the pin layout, refer to
Table 3-2.
Pin
Name
1
B-Line(in)
2
A-Line(in)
3
Shield
4
B-Line(out)
5
A-Line(out)
6
Shield
(note 2) There is no PE connection on the SJ-PB2/SJ-PBT2 option board. For proper grounding the shield of
the bus cable should be grounded by clamping it to a metal surface connected to PE. It's important that the
shield is grounded in order to avoid noise problems.
3.2 Profibus connectors
On the SJ-PB2/SJ-PBT2, any standard Profibus connector can be used. Depending on baudrate, IP-classing
and physical size of connector there are several different manufacturers and models, the prizing may also vary.
For more information it is recommended to contact the manufacturer, e.g., Siemens or Erni.
SJ-PBT2: In this case, the network connector is attached with SJ-PBT2 option board.
NP30
chip from ProfiChip.
Table 3-1 Pin Layout of SJ-PB2
Function
connection to PE(note 2)
-
-
Positive RxD/TxD according to RS 485 specification
Request To Send
Isolated GND from RS 485 side
Isolated +5V from RS 485 side
-
Negative RxD/TxD according to RS 485 specification
-
Table 3-2 Pin Layout of SJ-PBT2
Function
Positive RxD/TxD according to RS 485 specification
Negative RxD/TxD according to RS 485 specification
connection to PE(note 2)
Positive RxD/TxD according to RS 485 specification
Negative RxD/TxD according to RS 485 specification
connection to PE(note 2)
(note 1)
(note 1)
(note 1)
6
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