Re: 1-Wire Headache

["marcrfuller" <groups@xxxxxxxxxxxxxxxxxx>]

Hi Quinten,

The sensors are DS18B20's

If I understand the term parasitic power correctly then yes they are
using parasitic power - e.g the power is taken from the TEMP08 via the
comms line.

Cheers,

Marc

--- In ukha_d@xxxxxxx, Quinten Uijldert <yahoogroups2@...> wrote:
>
> And another question is if you are using parasite power or not?  And
> what Dallas sensors they are?  DS1820 or DS18S20?
>
> On 17 Jul 2007, at 19:42, Stuart Poulton wrote:
>
> > Marc,
> >
> > 85c is the reading that is returned as an error, normally that a
> > conversion wasn't able to be made.
> >
> > 2 questions
> >
> > 1 - Are you making connections to all 3 legs of the sensors ?
> > 2 - What sort of cabling are you using.
> >
> > I've successfully run 1-wire over 100m of cat5, using modules
that
> > daisy chained (modules of my own design)
> >
> > Cheers
> >
> > Stuart
> >
> > On 17 Jul 2007, at 17:49, Marc Fuller wrote:
> >
> >> Hey Guys,
> >>
> >> Just bought myself a TEMP08 to replace my Quasar logger. It's
all
> >> up and
> >> running and 3 of the sensors are working perfectly. My
problem is
> >> with
> >> the fourth.
> >>
> >> For some reason the fourth sensor that is at the end of the
bus,
> >> keeps
> >> showing a temperature of 85c, which is obviously not correct.
> >> Occasionally it will show the correct temperature, but mostly
it
> >> shows
> >> 85c. I replaced the probe with a new one and am getting the
same
> >> thing !
> >>
> >> Now I must admit I don't totally understand 1-wire yet.. this
is my
> >> first proper jump into it. So it could be that I have set up
the bus
> >> incorrectly ? or what else is likely to cause this problem ?
> >>
> >> The probes are wired in series and the farthest one is only
about 10
> >> meters away.
> >>
> >> Anyone got any ideas ? Could I just be really unlucky and
have two
> >> probes shorting out ?
> >>
> >> Any help appreciated
> >>
> >> Marc
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
> >
> >
> >
>