How do RS485 2-wire link?

[gemstone]

I want to use a rs232/485 convertor to communicate pc with a device.But i do not know how to link the two machines in rs485 2-wire mode?
who could tell me?
Thanks.
stone

[Mads]

Connect A to A and B to B...(A is normally - and B is +...but that may vary, try crossing if it does not work..incorrect polarity will not harm the equipment)

Make sure all units have been configured for 2-wire (often there is a dip-switch to do that...).

This is a nice web-site for more info about RS485:

http://www.bb-elec.com/tech_articles/rs422_485_app_note/table_of_contents.asp

[gemstone]

MADs,
First thank u for your help.
I think there are double A and double B pins(i.e.pin 4 and 8,pin 5 and 9)in a 485 device.the 232/485 connector has three pins(+,-and GND).I connect PIN 4and 8(shorten them) as B,5 AND 9 (shorten them)AS A in the device.then connect A to the "-" pin of the 232/485 connector,B to "+" and pin 1 to GND of the connector.If it does not work,then exchange them.Is it right?I wonder if I have clarified the answer.

[gemstone]

MADs,
First thank u for your help.
I think there are double A and double B pins(i.e.pin 4 and 8,pin 5 and 9)in a 485 device.the 232/485 connector who connected in the pc has three pins(+,-and GND).I connect PIN 4and 8(shorten them) as B,5 AND 9 (shorten them)AS A in the device.then connect A to the "-" pin in the 232/485 connector,B to "+" and pin 1 to GND of the connector.If it does not work,then exchange them.Is it right?I wonder if I have clarified the answer.

[Mads]

Correct.

[gemstone]

Dear MADS,
success!!!!!!!!!!! The reason is not the connecting but the command in the mannaul is incorrect.Thank u very much!!

[bo]

I am using Labview OPC server, rs232-485 converters, works well & easy if
you have the the server sotfware.

gemstone wrote in message
news:506500000008000000347F0000-1042324653000@exchange.ni.com...
> I want to use a rs232/485 convertor to communicate pc with a
> device.But i do not know how to link the two machines in rs485 2-wire
> mode?
> who could tell me?
> Thanks.
> stone

[gemstone]

Hi,bo
I have never heard the software you are using.How do u link the pc to a serial device?Have u shorten a couple of pins(4-8,5-9)or have u used only pin 4 and 5/(pin 8 and 9)? PLS let me know if u have time.
Thanks again.
gemstone