Re: LM35 - Length of cable ?

["Frank Mc Alinden" <armagh@xxxxxxx>]

Thanks Dave
                   
I wouldnt mind having a look even though you could write
what i know about C on the back of a postage stamp in caps. Please do.
www.armagh@xxxxxxx
Thanks

Frank
----- Original Message -----
From: "Dave McLaughlin" <dave@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Friday, May 31, 2002 10:40 PM
Subject: Re: [ukha_d] LM35 - Length of cable ?


> 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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