Computer Interfacing
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RS 485 nodes

adding rs 485 nodes increases noise


       Computer Interfacing Forum Index -> RS422 and RS485
Author Message
New User

Joined: 26 Oct 2010
Posts: 1

Oct 26, 2010 5:48 pm

i am trying to build an RS485 network using microcontrollers. i am using PC and a Rs232-Rs485 converter as my Master. when i add one microcontroller based circuit as node the communication is OK. When i add the second node the communication is ok but the data is noisy. But when i add the third node the whole communication halts. As i am testing in lab so i have not used twisted pair as the distance is also small (hardly i foot). i am also not termination because data rate is small enough, only 2400bps. can any body suggest something.


Oct 19, 2011 2:37 pm

Termination resistors and twist the cable. Are you driving a transmission line or a two wire capacitive pair? . . . <rhetorical>

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