Biasing Resistor for Rs-485 transmission line

[boogie]

Hello.
I want to ask how to calculate biasing resistor for RS-485 transmission line.
can you give me some references or some links to solve my problem.

Thanx in advanced

 

[IanP]

Typical values of bias resistors are between 1kΩ and 4.7kΩ ..
I use 2.2kΩ ..
Some more info here:
**broken link removed**
**broken link removed**

 

[vdaniel]

You can find very useful application notes for the RS485 in the National Semiconductor. www.national.com

Varuzhan

 

[7rots51]

you can pull up the A line with 470 ohm to vcc=5v at one device,and pull down the B line to GND with 470R also at same device.other nodes do not need pullup and pulldown.(one node is sufficient).

But you can use 4.7K for each node and all nodes have pullup/down.

 

[Azka]

I'm also find the solution to calculate best value for resistor in modbus communication.
i got problem sometime the communication is "hang". Master and Slave cannot communicate.
Hope others forumer can help.