On Tue, Dec 09, 2003 at 06:04:19AM -0800, Edi Im Hof enlightened us thusly > > Hi all > > The RS485 is defined to a maximum lenght of 1200m at 400kbps. I don't > need 400kbps, but up to 2500m of cable. Is it possible to extend to > this lenght with 9600bps? Yes. I would feel that cable quality would be important. The phones use twisted pairs to eliminate crosstalk over long distances.
> > Are there other standards for data transmission? Zillions. Network, usb, opto, & ieee1394 transmissions spring to mind as alternatives, but I'm sure to get shot down for saying that.
None of them works with 2500m on a bus...
> I have two wires > (plus power and ground), one master and up to 20 slaves. The maximum > distance between two slaves is 500m. A multimaster bus would be nice, > but is not a must. > > The network should also work if the cable is broken (up to the break). > With RS485, I would switch the termination with a relais.
There is the 'paperwork'side of this: Once you depart from the standard, your design will have to be tested more thoroughly by standards bodies (e.g CE approval testing) than if you are doing it by the book. The question of EMI also surfaces.
No CE needed, neither EMI is a great concern. See below.
> What else... Oh yes, the system is battery powered and should work > fron 25�C to -40�C. > > Any ideas? > > Edi Im Hof >
I'm intruiged by the temprature range. -40 I can imagine if your backside is frozen but how come it doesn't go above 25�C?
It's used in a glacier in the antarctic. The ice is about 0�C in a depth of 2500m and arround -40�C on the surface.
I have to test the units in the office and I don't like to cool it down to 0�C or go to the climate chamber for every test...
Edi Im Hof
--
With best Regards,
Declan Moriarty. -- Author: Declan Moriarty INET: [EMAIL PROTECTED]
Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ + IH electronic + Phone: ++41 52 320 90 00 + + Edi Im Hof + Fax: ++41 52 320 90 04 + + Doernlerstrasse 1, Sulz + URL: http://www.ihe.ch + + CH-8544 Rickenbach-Attikon + E-Mail: [EMAIL PROTECTED] + + Switzerland + + ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-- Author: Edi Im Hof INET: [EMAIL PROTECTED]
Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
