Re: Tell me about 1-wire...

["turner228" <kevin@xxxxxxxxxxxxxxxx>]

Gents
Just thinking about the physical network structure, you would be well
advis=
ed to read this application note from maxim, the supplier of the one wire
d=
evices:

Guidelines for Reliable Long Line 1-Wire=AE Networks
http://pdfserv.maxim-ic.com/en/an/AN148.pdf

Stuarts board has 2 RJ45 connectors, these permit the use of ready made,
pr=
e-tested, cables as well as making your own up using the RJ45 connectors.
I=
f you make your own up I would recommend the use of the readily available
R=
J45 network cable tester

The board also has has a 3 way terminal block for the addition of
additiona=
l sensor(s) "dropped off" from this pcb

When installing long or complex networks it is always best to be cautious
a=
nd to install progressively and test the functionality right back to the
in=
terface as you go along.

One of the plus points of the rj45 connectors is it is simple to
disconnect=
parts of the network later when fault-finding

I don't recall right now how much i paid for my boards, but i did not
consi=
der them expensive.

HTH

KevinT


--- In ukha_d@xxxxxxx, "leewild80" <muddyboots@...> wrote:
>
> Stuart
>=20
> I was planning on using owfs on my Linux box.
> Reading the sensor values then looks incredibly simple, I can do
pretty m=
uch anything I want then using scripts, cron and mysql...
>=20
> Lee
>=20
> --- In ukha_d@xxxxxxx, Stuart Poulton <stuart@> wrote:
> >
> > Hi Guys,
> >=20
> > Not sure what plans you have for software for reading your 1-wire
nets =
?
> >=20
> > Cheers
> >=20
> > Stuart
> >=20
> > On 2 Nov 2010, at 20:38, Simon Haslam wrote:
> >=20
> > > I've been pondering this too. I think you'd mainly use them
at physic=
ally separate locations in the 1-wire network - where you've got several
se=
nsors close together it might be overkill (especially given that the
sensor=
chips are so cheap). I've bought some of those 1-wire metal probes which f=
it nicely in the pockets in my solar cylinder, and will have some
flow/retu=
rn etc sensors strapped to pipes - at the moment they're just pushed into
b=
readboard but I think I'll shorten the leads as much as possible and then
j=
oin them all back to a small junction box, which itself may have 2 RJ45
soc=
kets on it (perhaps using one of Stuart's boards).
> > >=20
> > > One concern is creating stars on the network (which wouldn't
be the c=
ase if each sensor was mounted on a twin RJ45 PCB) - hopefully it won't
mat=
ter where the sensor leads are only ~50cm long. For longer leads (e.g. I
ha=
ve one to a DS18B20 I'm planning to install next to the weather
compensatio=
n thermistor for the boiler) I'm planning to run Cat 5 with DQ
"up" to the =
sensor on blue and "back" on orange (and likewise blue/white and
oracle/whi=
te for GND) - I've still not decided how to terminate that though.
> > >=20
> > > This is mostly guesswork for me ;-)
> > >=20
> > > Simon
> > >=20
> > >=20
> > >=20
> > >=20
> >=20
> >=20
> >=20
> > [Non-text portions of this message have been removed]
> >
>




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