Comments on: RS-485 interface for connecting multiple devices http://www.scienceprog.com/rs-485-interface-for-connecting-multiple-devices/ ScienceProg serves scientific, embedded, biomedical engineering, physics based contents. If you want your article or scientific project to be on this site, do not hesitate to contact and send to scienceprog@gmail.com. Fri, 08 Aug 2008 01:17:50 +0000 http://wordpress.org/?v=abc By: scienceprog http://www.scienceprog.com/rs-485-interface-for-connecting-multiple-devices/#comment-3239 scienceprog Mon, 27 Nov 2006 10:01:34 +0000 http://www.scienceprog.com/rs-485-interface-for-connecting-multiple-devices/#comment-3239 "When using the default RS485 receivers with an input resistance of 12 kΩ it is possible to connect 32 devices to the network. Currently available high-resistance RS485 inputs allow this number to be expanded to 256." So all depends on receiver input resistance. About constructive discussions - I hadn't chance yet to try RS485 interface, so this is still theoretical subject to me. “When using the default RS485 receivers with an input resistance of 12 kΩ it is possible to connect 32 devices to the network. Currently available high-resistance RS485 inputs allow this number to be expanded to 256.”
So all depends on receiver input resistance.
About constructive discussions - I hadn’t chance yet to try RS485 interface, so this is still theoretical subject to me.

]]> By: Mark http://www.scienceprog.com/rs-485-interface-for-connecting-multiple-devices/#comment-3194 Mark Sat, 25 Nov 2006 15:21:07 +0000 http://www.scienceprog.com/rs-485-interface-for-connecting-multiple-devices/#comment-3194 Thanks for this site and this article. It answered a couple of questions for me I am building this : http://www.pcdimmer.de I know the 2313 chip is obsolete but i have a couple dozen already. I would like to know if this limit of 32 nodes is theoretical or physical? I would plan on chaining these boards and when a board wants to communicate, it will pull the DE/TE line low or high, and that each node would have to check if the line is in the proper state before it tries to send. Each node is addressable so they would ignore data destined for either the master or any other slave. I would like to talk more about this to you if you have time. Thanks again for the good information. Mark Thanks for this site and this article.

It answered a couple of questions for me

I am building this :

http://www.pcdimmer.de

I know the 2313 chip is obsolete but i have a couple dozen already.

I would like to know if this limit of 32 nodes is theoretical or physical?

I would plan on chaining these boards and when a board wants to communicate, it will pull the DE/TE line low or high, and that each node would have to check if the line is in the proper state before it tries to send. Each node is addressable so they would ignore data destined for either the master or any other slave.

I would like to talk more about this to you if you have time.

Thanks again for the good information.
Mark

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