Paul, Ah, thanks for the description, very helpful. I'm almost there.
I think I found a possible bug when reading the alarm values through the perl interface. I can read the voltage, but not the alarm. When I do a perl get on "volt.X", all is good. When I do a perl get on "alarm/low.X", I get a directory listing of the alarm directory. From my print logs (perl): 06/10/06 09:49:27 AM Owfw_Item::get /20.DB2506000000/volt.B data: 1.84003 06/10/06 09:49:27 AM Owfw_Item::get /20.DB2506000000/alarm/low.B data: high.ALL,high.A,high.B,high.C,high.D,low.ALL,low.A,low.B,low.C,low.D However, when I "cat 20.DB2506000000/alarm/low.B" via the file system, I get the proper value of "0". Jim Paul Alfille wrote: > On 6/9/06, Jim Duda <[EMAIL PROTECTED]> wrote: > >>I measured the DC voltage, and discovered a cold solder joint on the >>PCB. The DS2450 is reading voltage correctly now. >> >>Do the Alarms work? I don't follow how to set and/or detect an alarm. >>I want to know if the voltage drops below 1V DC. > > I think they work -- easy enough to check. > >>I read the documentation, but it wasn't quite obvious what I should >>be doing. > > > I can see why the documentation was dissapointing. It hasn't been updated. > I'll do that today and it can be read at > http://www.owfs.org/index.php?page=ds2450 > > I believe the steps are > > 1. Set alarm limits, alarm enable and powered mode > echo "1.0" > set_alarm/voltlow.A > echo "1" > set_alarm/low.A > echo "1" > power > > 2. Loop: > while : ; do > echo "1" > simultaneous/voltage > ls alarm > and look for it there > done > > 3. Actually, all that is a rather silly way to do it if you don't have > a lot of other 1-wire activity. > Acording to my reading of the datasheet: > http://pdfserv.maxim-ic.com/en/ds/DS2450.pdf > Even powered, the DS2450 doesn't do continuous conversion, just allows > other activity during conversion and speed up converions by .16 > millseconds > > So you have to trigger a read. > > You can just poll the DS2450 and read the voltage and test. > The real advantage of the scheme above with the "simultaneous" is that > you don't need to pause during the conversion. > I suspect the "alarm" directory would reflect a prior "simultaneous" > since only a read would pause for it to be done, but that's ok. > > Does this answer your questions? > > Paul Alfille > > set "set_alarm/volthigh.A to "5.0" (so it won't trigger) > for A through D, os use > set "set_alarm/voltlow.ALL to "1.0,1.0,1.0,1.0" > set "set_alarm/volthigh.ALL to "5.0,5.0,5.0,5.0" > > > >>I do have the DS2450 locally powered. I've set the POWER bit checkbox. >>I also have the PIO check box set for the channels I want to monitor. >> >>Do the conversions happen continuously when power is set to true? Or, >>only when I attempt to read the voltage? >> >>Thanks, >> >>Jim >> >>Paul Alfille wrote: >> >>>Can you test a DC voltage? It's always possible that we aren't reading >>>voltages correctly. >>> >>>Paul Alfille >>> >>>On 6/9/06, Jim Duda <[EMAIL PROTECTED]> wrote: >>> >>> >>>>Yes, 60 Hz. I would expect the capacitor to remain at some steady state >>>>voltage, somewhere around 1.5V. I don't have access to an oscillosope at >>>>home. >>>> >>>>Jim >>>> >>>> >>>>"Paul Alfille" <[EMAIL PROTECTED]> wrote in message >>>>news:[EMAIL PROTECTED] >>>>Not at all off-topic. >>>>I'm no expert, but the schematic is at >>>>http://www.hobby-boards.com/catalog/links/hvac2-r1/HVAC%20Monitor%20v2.0%20Schematic.pdf >>>> >>>>With 1M resitor and 1uF capacitor, the time constant is 1 second. What is >>>>the frequency of your AC? 60Hz? >>>> >>>>Paul Alfille >>>> >>>> >>>>On 6/7/06, Jim Duda <[EMAIL PROTECTED]> wrote: >>>> >>>> >>>>>I apologize if this is off topic, since owfs seems to handle DS2450 just >>>>>fine, as best I can surmise. >>>>> >>>>>I purchased a "HVAC Monitor Kit" from Hobby Boards. The description of >>>>>the board states that it can measure any voltage up to 28V AC or DC. >>>>>The design has a diode and a resistive voltage divider (100K/1M) on the >>>>>front-end of the DS2450 voltage inputs. >>>>> >>>>>For the signal I want to monitor, my DVM measures 15V AC at the terminal >>>>>lug of the HVAC Monitor. However, via owfs HTTP, I see various voltages >>>>>between 240 mV and 1.5V, seems to be all over the place, like maybe a >>>>>sinusoid :-) >>>>> >>>>>Can anyone offer any tips on how I might measure an AC voltage with this >>>>>thing? >>>>> >>>>>Jim >>>>> >>>>> >>>>> >>>>>_______________________________________________ >>>>>Owfs-developers mailing list >>>>>[email protected] >>>>> >>>> >>>>https://lists.sourceforge.net/lists/listinfo/owfs-developers >>>> >>>> >>>> >>>> >>>>________________________________ >>>> >>>> >>>> >>>> >>>>________________________________ >>>> >>>> >>>>_______________________________________________ >>>> >>>>Owfs-developers mailing list >>>>[email protected] >>>>https://lists.sourceforge.net/lists/listinfo/owfs-developers >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>>_______________________________________________ >>>>Owfs-developers mailing list >>>>[email protected] >>>>https://lists.sourceforge.net/lists/listinfo/owfs-developers >>>> >>>> >>>> >> >> >> >>_______________________________________________ >>Owfs-developers mailing list >>[email protected] >>https://lists.sourceforge.net/lists/listinfo/owfs-developers >> _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
