SmartFlex SR304
Figure 42: RS232 connector
Connection of RS485 connector:
Pin
Signal
Description
Direction
1
TxRx+
RS485 B (+)
Input/Output
2
TxRx-
RS485 A (-)
Input/Output
3
TxRx+
RS485 B (+)
Input/Output
4
TxRx-
RS485 A (-)
Input/Output
Table 22: Connection of RS485 connector
The termination resistor can be activated directly on the port board using a jumper (termination
resistor is part of the port board).
Connection of RS422 connector:
Pin
Signal
Description
Direction
1
RxD+
RS422 (+)
Output
2
RxD-
RS422 (-)
Output
3
TxD+
RS422 (+)
Input
4
TxD-
RS422 (-)
Input
Table 23: Connection of RS422 connector
Figure 43: RS485/422 connector
The selection of either RS485 or RS422 can be performed by using jumpers on the
board. The points where jumpers have to be mounted are shown on the port (see the fig-
ure below). Three jumpers are required for the RS485 interface or one jumper for the RS422
interface.
The default configuration is RS485 with termination off.
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