no, here i´m using a 30 meters without resistor i´m not using parasite power, all ds1820 are powered
2011/2/15 Mick Sulley <[email protected]>: > I would guess the longest cable distance from adapter to sensor is about > 30-40 metres. I currently have 20 temperature sensors, a mix of DS18S20 > and DS18B20 and a couple of DS2406. I use a DS9097U adapter plugged > into a genuine serial port. > > The topology is basically a Cat5 backbone with branches off to the > sensors in 2 pair telephone cable, the branches being a few metres only. > > The system runs on an Ubuntu server at one end of the backbone, running > python code using pyowfs. I use a desktop for development and to test > out stuff I unplug from the server and plug in the desktop, but that is > roughly in the middle of the backbone, so that really creates a slightly > different topology. The system seems to run reliable on the server, but > then I don't plug stuff in and out when running that. > > I have seen in the docs for one device that you should have a 150ohm > resistor in each sensor line. I don't have that at present, could that > cause any problems? > > Cheers > Mick > > On Tue, 2011-02-15 at 09:47 +0100, Markus Gaugusch wrote: >> Hi Mick! >> >> I've experienced such problems as well, but it only occurs if the network >> gets too large. E.g. if I connect (even an empty!) cable with 20 meters, >> my network breaks down completely. How large is your network, which >> topology (bus, star, ...), which adaptor do you use, etc.? >> >> br, >> Markus >> >> On Feb 14, Mick Sulley <[email protected]> wrote: >> >> > Hi, >> > >> > If I run owhttp I can see the devices on my network. If I then plug >> > some more devices into the network and refresh the screen it seems to >> > screw up, sometimes I can just see the original sensors, sometimes I see >> > nothing at all. >> > >> > What is the official expectation here? Should I be able to 'hot plug' >> > sensors on the network or is it expected that I should need to shut down >> > and restart? >> > >> > I am running owhttp in debug mode and when I loose all devices I am >> > seeing connection timeouts on my serial port. I don't know if the root >> > cause is a hardware problem with my serial port, so I would appreciate >> > feedback on what I should be seeing. >> > >> > Thanks >> > Mick >> > >> > >> > ------------------------------------------------------------------------------ >> > The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE: >> > Pinpoint memory and threading errors before they happen. >> > Find and fix more than 250 security defects in the development cycle. >> > Locate bottlenecks in serial and parallel code that limit performance. >> > http://p.sf.net/sfu/intel-dev2devfeb >> > _______________________________________________ >> > Owfs-developers mailing list >> > [email protected] >> > https://lists.sourceforge.net/lists/listinfo/owfs-developers >> > >> > >> > >> > > > > ------------------------------------------------------------------------------ > The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE: > Pinpoint memory and threading errors before they happen. > Find and fix more than 250 security defects in the development cycle. > Locate bottlenecks in serial and parallel code that limit performance. > http://p.sf.net/sfu/intel-dev2devfeb > _______________________________________________ > Owfs-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/owfs-developers > > -- Roberto Spadim Spadim Technology / SPAEmpresarial ------------------------------------------------------------------------------ The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE: Pinpoint memory and threading errors before they happen. Find and fix more than 250 security defects in the development cycle. Locate bottlenecks in serial and parallel code that limit performance. http://p.sf.net/sfu/intel-dev2devfeb _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
