Paul I do have that thanks anyway. I know that open stubs can create problems but I used it to see if it was the sensor I connected to it or the cable or whatever it might be. If I connect a temperature sensor on a 1 meter RJ45 cable it is fine and works as expected. If I use a cable say 5 meters long with the same sensor connected it is not seen, the light on the LinkUSB stays on all the time dimly and glows brigher when my script checks the bus for the sensors temperature. I have had this issue since the lightning strike 3 weeks ago. I am now using a different Raspberry pi, a different LinkUSB or an RPI2 bought new after the strike and new cables. As I say I have tested all the sensors and they work fine all connected in series on 1 meter RJ45 cables. Use a longer new cable to connect another sensor and every sensor on the network disappears.
I am at a loss I have tested all sensors and I have a cable tester which shows all cables are straight through with no shorts or open circuits. They all work fine for gig Ethernet. I have put my scope on the data and return wires at the LinkUSB end and that does not show any noise on the network even with a long cable connected to a sensor, only the calls for the sensor are seen on it. I have built a new sensor to run parasitic and it works on a short cable but not a long one. I have installed owfs on my Linux desktop and it does the same. Any ideas welcome. Colin > > ------------------------------ > > Message: 2 > Date: Wed, 29 Jan 2014 08:32:35 -0500 > From: Ziggy <[email protected]> > Subject: Re: [Owfs-developers] 1-wire network problems > To: "OWFS (One-wire file system) discussion and help" > <[email protected]> > Message-ID: <[email protected]> > Content-Type: text/plain; charset=us-ascii > > Please check out Dallas/Maxim app note 148. Gives a lot of insight into > making things work and why they don't. > > <http://pdfserv.maximintegrated.com/en/an/AN148.pdf> > > Open stubs are a bad thing and cause reflections on the wire, disrupting > communication. They can also act like antennas, picking up noise which could > be the activity you see on the LED - but not sure what drives it since I > couldn't find a schematic for the LinkUSB. > > Paul > > On Jan 28, 2014, at 3:52 AM, Colin Tinker <[email protected]> wrote: > > Eric > > They are truly in series. The LinkUSB light will come on dimly all the > time with a long cable with nothing attached to it and stay on all the > time dimly. The light should only be on when there is traffic on the > network. > > Colin > > > Colin, > > Are your devices truly connected in series or are there some stubs? > > If you have a power injector in the system I?m not sure why the LinkUSB light > would dim at all. > > Eric > > > > ------------------------------------------------------------------------------ > WatchGuard Dimension instantly turns raw network data into actionable > security intelligence. It gives you real-time visual feedback on key > security issues and trends. Skip the complicated setup - simply import > a virtual appliance and go from zero to informed in seconds. > http://pubads.g.doubleclick.net/gampad/clk?id=123612991&iu=/4140/ostg.clktrk > _______________________________________________ > Owfs-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/owfs-developers > > > > > ------------------------------------------------------------------------------ WatchGuard Dimension instantly turns raw network data into actionable security intelligence. It gives you real-time visual feedback on key security issues and trends. Skip the complicated setup - simply import a virtual appliance and go from zero to informed in seconds. http://pubads.g.doubleclick.net/gampad/clk?id=123612991&iu=/4140/ostg.clktrk _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
