We've attempted to do this for our own uses (somewhat similar). Unfortunately, owfs appears to have bugs in this area and does not perform correctly. I hope to have time to do some low-level debugging with the 2450 datasheet to figure out where the problem is and submit a specific bug report.
In general, you need to set the alarm criteria for the high and low, then you have to do an "ls" in the alarming folder (preferably in the uncached folder). We use alarming extensively on the 2406 for detecting pio transitions (used to detect relay-based motion detector's activity). Alarming has made the onewire system a feesable bus for our purposes, and we have run into major issues trying to simulate alarming on 2450's with bus saturation. As soon as I have time to look into this more, I will post my findings to this list. As far as we've been able to extrapolate so far, the 2450 is not properly "set up" for alarming by owfs. --Jim On Thu, Feb 25, 2010 at 4:15 PM, Paul Alfille <paul.alfi...@gmail.com> wrote: > When in alarm condition, the device should appear in the /alarm directory. > > OWFS won't automatically poll the device, you need to do this in your > program. (It can be as simple as a shell script with a loop and a "sleep" > command). > > Paul Alfille > > On Thu, Feb 25, 2010 at 6:40 PM, Alessio Sangalli <ale...@manoweb.com> > wrote: >> >> Just a question: in what way I can use DS2450's alarm threshold feature? >> >> Basically, I want to "monitor" and "detect" overvoltages coming on the >> Vin. Say I want to "report" everytime the voltage goes above 20VDC (when >> the nominal is 14VCD). >> >> I could setup a voltage divider so that I can measure up to say, 75V and >> still be in the range of the 5.12VDC the DS2450 can sample from. >> >> And this is all under control. >> >> How do I use the software to notify when I get this overvoltage? This is >> what I do not understand, right now :( >> >> Thank you >> Alessio >> >> >> >> >> ------------------------------------------------------------------------------ >> Download Intel® Parallel Studio Eval >> Try the new software tools for yourself. Speed compiling, find bugs >> proactively, and fine-tune applications for parallel performance. >> See why Intel Parallel Studio got high marks during beta. >> http://p.sf.net/sfu/intel-sw-dev >> _______________________________________________ >> Owfs-developers mailing list >> Owfs-developers@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/owfs-developers > > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > Owfs-developers mailing list > Owfs-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/owfs-developers > > ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
