From owner-freebsd-questions@FreeBSD.ORG Fri Oct 13 11:29:06 2006 Return-Path: X-Original-To: freebsd-questions@FreeBSD.org Delivered-To: freebsd-questions@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5FD4E16A403 for ; Fri, 13 Oct 2006 11:29:06 +0000 (UTC) (envelope-from bsam@ipt.ru) Received: from mail.ipt.ru (mail.ipt.ru [80.253.10.82]) by mx1.FreeBSD.org (Postfix) with ESMTP id D99A743D45 for ; Fri, 13 Oct 2006 11:29:05 +0000 (GMT) (envelope-from bsam@ipt.ru) Received: from admin.sem.ipt.ru ([192.168.12.1] helo=ipt.ru) by mail.ipt.ru with esmtp (Exim 4.62 (FreeBSD)) (envelope-from ) id 1GYLDs-000LvL-IQ; Fri, 13 Oct 2006 15:29:04 +0400 Received: from bsam by ipt.ru with local (Exim 4.63 (FreeBSD)) (envelope-from ) id 1GYLEu-00015X-1V; Fri, 13 Oct 2006 15:30:08 +0400 To: phil@primeradesigns.com References: <1160735521.15042.7.camel@sled10.27sjcr> <81769636@srv.sem.ipt.ru> <1160738078.15042.17.camel@sled10.27sjcr> From: Boris Samorodov Date: Fri, 13 Oct 2006 15:30:08 +0400 In-Reply-To: <1160738078.15042.17.camel@sled10.27sjcr> (Philip M. Brown's message of "Fri, 13 Oct 2006 12:14:37 +0100") Message-ID: <15688191_-_@srv.sem.ipt.ru> User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: freebsd-questions@FreeBSD.org Subject: RS-485 net (was: Re: moxa multiport serial cards) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 13 Oct 2006 11:29:06 -0000 On Fri, 13 Oct 2006 12:14:37 +0100 Philip M Brown wrote: Please, keep CC to freebsd-questions for archieves sake so others may find that info. And, please don't top-post. Thanks for your patience. > On Fri, 2006-10-13 at 15:06 +0400, Boris Samorodov wrote: > > > > If your hardwares use RS-485 ports than you can connect (up to > > 32/64/.. -- depends on port chips) to RS-485 net and control them > > through one master device (one RS-485 port at your server). Setting up > > an RS-485 net has it own tips and tricks which you may find at > > Google. > ok, thanks for super quick response. You are welcome. ;-) > it seems my hardware i need to connect to is rs-232. You may check the documentation for your hardware. > however as I am bemused with 485 can you please explain, is it as i > expected, where one of the db25 leads from the card could the be split > into multiple devices or do i need another box in between. All RS-485 devices should be connected to one line (2/3/4/5 wires possible). Maximum number of those devices depends on their chip properties. Maximun line length (as for standart) is 1200 meters at maximum speed. The line should be terminated with 120 Ohm resistor at both ends. Only one device is a master and should initiate a conversation. All others are slaves and only answer when asked. Slave devices are addressed by their net address. And so on... More info is available at Google. WBR -- Boris Samorodov (bsam) Research Engineer, http://www.ipt.ru Telephone & Internet SP FreeBSD committer, http://www.FreeBSD.org The Power To Serve