Re: Re: Tell me about 1-wire...

[Simon Haslam <simon_haslam@xxxxxxxxxxx>]

Lee

I'm working on a similar thing - primarily using 1-wire for monitoring and
=
managing my central heating.

I spoke to HomeChip and they convinced me that it was better to go for the
=
LinkUSB 1-wire controller (http://www.homechip.com/catalog/product_info.php=
?cPath=3D22&products_id=3D158) as it's supposed to be more reliable due
to =
the way serial to USB is implemented, plus some network reliability
enhance=
ments. The HomeChip chap was very helpful so I've no reason to think this
w=
as just a =C2=A310 up-sell. I've been using that for about a month without
=
problems - it was recognised fine by Ubuntu linux. At the moment I'm using
=
Digitemp to read the sensors and RRDtool to graph them, though intend to
mo=
ve to owfs.

I'm using Clipsal pink CAT5 cable for my 1-wire network and will probably
u=
se RJ45 plugs (rather than RJ11/12) as they seem to be more common even
tho=
ugh they are bulkier. From the start I have used the 5V supply from the
Lin=
kUSB too, rather than relying on parasitic power. I did increase the poll
t=
ime (up to 1.2s I think) which reduced the number of failed readings.

Last week I've just received an I/O board (http://www.hobby-boards.com/cata=
log/product_info.php?products_id=3D1554) which I'm planning to use to
contr=
ol 24V actuators on a 7 port manifold connected to the radiators.

I immediately found the solar cylinder temperature measurements very
useful=
- in fact I've just re-plumbed the outlets to try to reduce thermo-syphoni=
ng and standing heat losses.

You say you've got 3 networks due to the natural layout. Though not
recomme=
nded, a star topology may work if there aren't too many devices, I don't
kn=
ow. Otherwise have you considered running the data/ground "back"
through a =
spare pair so that you don't need a hub? Then your network becomes one
long=
one that goes "up and down" 3 legs (if you see what I mean!).
That would s=
ave the hub and so should reduce complexity. There's also a paper on
Maxim'=
s site about designing long 1-wire networks, which I take to also mean
what=
to do to get shorter networks to run most reliably.

Good luck!


Simon

--- On Tue, 26/10/10, ben_mccormack2000 <yahoogroup@xxxxxxx> wr=
ote:

From: ben_mccormack2000 <yahoogroup@xxxxxxx>
Subject: [ukha_d] Re: Tell me about 1-wire...
To: ukha_d@xxxxxxx
Date: Tuesday, 26 October, 2010, 16:02







=C2=A0



=20=20


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=20=20=20=20=20=20
=20=20=20=20=20=20
Couple of pointers that may help. I have a load of 1-wire is the hous=
e but never managed to wire it all up!!



http://www.klein.com/thermd/ - Guy
doing similar to you and using linux bac=
kend



I use the HA7NET for the hub.



If you also search for my mails I asked similar questions about 1-2 years
a=
go



Ben



--- In ukha_d@xxxxxxx, "leewild80" <muddyboots@...> wrote:

>

> Afternoon all

>=20

> Am trying to read up about the use of 1-wire networks & sensors
for tempe=
rature monitoring.

>=20

> Tried to search this list, but as someone has the text
"1-wire" embedded =
at the end of all their posts, I couldn't see wood for't trees... :)

>=20

> I'd quite like to monitor temps in several places, for example:

> 1) At various points on my thermal store & associated pipework

> 2) On my UFH manifold, eg F&R temps to the manifold itself and
also to ea=
ch zone

> 3) Same as 2) but on the manifold I'll soon be installing to run all
my r=
ads off.

>=20

> Each of the above are in quite separate locations in the house, so I
fors=
ee having 3 separate networks, one to each area, running back to a PC.

>=20

> I have a Linux PC that's running most of the time for file storage and
in=
tend to use OWFS to get the data back from the sensors. It has USB ports
bu=
t no older style serial port.

>=20

> I guess what I'm wanting to know is:

> 1) How can I cater for the 3 separate networks ? I have read about
1-wire=
hubs but haven't yet seen where I could buy these from. I guess I can't ju=
st "star" 3 long legs together, or can I ?

> 2) I presume I can use Cat5 UTP to run the networks, and hang the
sensors=
off this ? Route the cat5 around all the sensor locations and attach them =
to it via short tails ?

> 3) Would I need to provide additional power to the networks to power
the =
sensors, or is there some kind of hub device that will do this for me ?

> 4) Will the DS9490R USB interface from Homechip be all I need to hook
up =
to my PC and be useable with OWFS ?

> (http://www.homechip.com/catalog/product_info.php?cPath=3D22&products_id=
=3D30)

>=20

> If there's a handy guide that tells me all of this, feel free to point
me=
at it !

>=20

> Many thanks

> Lee

>





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