RS-485 wiring information

FAQ #100152

There are confusing screw terminal identifier terminologies around. Depending on the manufacturer the identifiers used are in conflict to the identifiers you can find in SBC manuals.

 

General
RS-485 is a Bus-system, therefore the signal wires shall not be crossed.

Converter
PCD
Rx-Tx (or D)
 Rx-Tx
/Rx-/Tx/ (or /D) 
 /Rx-/Tx

Sometimes "+Data" and "-Data" can be found on devices. Then "+Data" propably has to be connected to "/Rx-/Tx" (or /D) and "-Data" to "Rx-Tx" (or D).

Converters
Some products form other manufacturers (p.e. RS232 - RS485 converters) are often inversly indicated. Therefore it is sometimes necessary to cross the wires.

Converter
PCD
Rx-Tx 
 /Rx-/Tx/
/Rx-/Tx/
 Rx-Tx


Profibus and Profi-S-I/O 

Profibus
Colour
PCD7.T160 D-Sub 9pin on PCDPort 2 on PCD3.M3 and M6
A=RxD /TxD-N
 green
 D
pin 8 
D
B=RxD /TxD-P
 red
 D/
pin 3
/D


Example for the port 3 of the PCD3.M5540 as Serial-S-Bus
RS485 connection (Serial-S-Bus) between PCD3.M5540 port 3 (S-Net D-Sub used as RS485 Serial-S-Bus) and PCD2.M5540 port 2 (connector block X3):

PCD3.M5540 (D-Sub "S-Net", port 3)
PCD2.M5540, X3, port2  equipped with a PCD7.F110
pin 3
terminal 2
pin 8
terminal 1


 

Categories

PCD7 / Txxx

PG5 2.0 / Profibus FMS

PG5 2.0 / Profibus DP

PG5 2.0 / Serial-S-Bus

PG5 2.0 / Profi-S-I/O

Last update: 29.05.2015 10:31

First release: 17.06.2004 13:42

Views: 22598

The requested software / document is no longer marketed by Saia-Burgess Controls AG and without technical support. It is an older software version which can be operated only on certain now no longer commercially available products.

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