Re: LM35 - Length of cable ?

["Dave McLaughlin" <dave@xxxxxxx>]

Hi Frank,

I can supply you with C source code for the AVR devices (only the SPI
is
done in assembler) so you can see how to setup the devices. It is
fairly
easy to get working, Took me only about 15mins the first time I tried to
get
2 devices talking.

Dave...

----- Original Message -----
From: "Frank Mc Alinden" <armagh@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Friday, May 31, 2002 1:25 PM
Subject: Re: [ukha_d] LM35 - Length of cable ?


> Thanks Dave
>                    
I have downloaded and read up a while back on the pic
> chip you refer to and the can bus protocol .It was using the Allen
Bradley
> stuff at work that drew my attention to it . I dabble with the pic,s
and
> thought about using the can system but thought it was out of my depth.
Im
> going to have to have another look at it. How do you set message
priority
> level ? Is it hard to get up and running. Im only a novice when it
comes
to
> comms.
> Frank Mc
> ----- Original Message -----
> From: "Dave McLaughlin" <dave@xxxxxxx>
> To: <ukha_d@xxxxxxx>
> Sent: Friday, May 31, 2002 10:10 PM
> Subject: Re: [ukha_d] LM35 - Length of cable ?
>
>
> > Hi Frank,
> >
> > Multi master is the greatest thing I like about it. Works very
similar
to
> > the way Ethernet talks on the bus as regards detecting
collisions,
> priority
> > etc.
> >
> > Go to www.kvaser.se and have a look at the documentation section
as
there
> is
> > loads to read.
> >
> > The Microchip MCP2510 is what I currently use and is easy to
interface
> being
> > SPI. You only need 2 chips (plus the CPU of course) and you then
have a
> CAN
> > bus interface. There are microcontrollers with built in CAN
and
Microchip
> > and others do them but the costs of the dev kits put me off using
them.
I
> > use the Atmel AVR with the MCP2510 and I can then design whatever
I need
> as
> > I already have the code to talk to them.
> >
> > The nice thing about CAN that I like, is that you can get the
device to
> > transmit anytime without being requested to, as when using a
Master-Slave
> > setup with RS485. The message with the highest priority gets the
bus and
> the
> > other has to wait (meaured in uS in some cases) till the current
device
> > completes transmission.
> >
> > Even the lowly Skoda Octavia uses CAN bus these days.
> >
> > Once you have played with CAN it opens up some serious
control
> > possibilities. I am currently wiring up my garage with CAN to
detect and
> > control my central heating boiler and the open/closed state of
the
garage
> > door. All on the same twisted pair. I have other ideas to add and
the
> beauty
> > of CAN is the ability to add devices without having to change any
code
on
> > the existing devices, other than the one that is going to receive
the
new
> > data.
> >
> > A bit long winded but you should checkout the link above as it
has some
> very
> > interesting reading.
> >
> > Regards
> > Dave...
> >
> > ----- Original Message -----
> > From: "Frank Mc Alinden" <armagh@xxxxxxx>
> > To: <ukha_d@xxxxxxx>
> > Sent: Friday, May 31, 2002 1:01 PM
> > Subject: Re: [ukha_d] LM35 - Length of cable ?
> >
> >
> > > Hi Dave
> >
>            
Whats the difference between rs485 comms and the Can bus ?
> is
> > it
> > > the protocol . I see Microchip have can bus chips. Are they
easy to
use?
> > > Some of the industrial (Allen Bradley) plc suppliers use the
can bus
> > system.
> > > What are the advantages?
> > >
> > > Frank Mc
> > > ----- Original Message -----
> > > From: "Dave McLaughlin" <dave@xxxxxxx>
> > > To: <ukha_d@xxxxxxx>
> > > Sent: Friday, May 31, 2002 9:55 PM
> > > Subject: Re: [ukha_d] LM35 - Length of cable ?
> > >
> > >
> > > > Mark,
> > > >
> > > > My weather station has about 20ft or so of 4 core
unscreened and it
> > works
> > > > fine. There is a small amount of noise but by averaging
samples I
get
> a
> > > > better readout. Only changes by about 0.1 of a degree
and
considering
> > the
> > > > accuracy of the LM35 this is acceptable anyway.
> > > >
> > > > Once I get my act together I will have a CAN bus based
sensor
> interface
> > > that
> > > > should alleviate this problem and allow you to make
runs as long as
> 500m
> > > > without problems of noise. I already have designs that
can read
> digital
> > > data
> > > > but not yet with the analog.
> > > >
> > > > Dave...
> > > >
> > > > ----- Original Message -----
> > > > From: "Frank Mc Alinden"
<armagh@xxxxxxx>
> > > > To: <ukha_d@xxxxxxx>
> > > > Sent: Friday, May 31, 2002 12:30 PM
> > > > Subject: Re: [ukha_d] LM35 - Length of cable ?
> > > >
> > > >
> > > > > Mark
> > > > >         If
its only 20 ft  the 4 core security cable would work .
I
> > dont
> > > > > imagine you would be that unlucky .
> > > > >
> > > > > Frank Mc
> > > > > ----- Original Message -----
> > > > > From: "Mark Marooth"
<MMarooth@xxxxxxx>
> > > > > To: <ukha_d@xxxxxxx>
> > > > > Sent: Friday, May 31, 2002 9:19 PM
> > > > > Subject: Re: [ukha_d] LM35 - Length of cable ?
> > > > >
> > > > >
> > > > > >
> > > > > >
> > > > > > Hi Frank,
> > > > > >
> > > > > > Runs should be no longer than 20 feet through
the roof space.
> > You've
> > > > also
> > > > > > confirmed what I suspected about noise, as I
am running thorugh
> roof
> > > > > space,
> > > > > > think I'll use something shielded.
> > > > > >
> > > > > >
> > > > > > Mark
> > > >
> > > >
> > > >
> > > >
> > > > For more information: http://www.automatedhome.co.uk
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> > > >
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> > > >
> > >
> > >
> > >
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