Sorry. No I did it in software written in Delphi....

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Vasile Surducan
Sent: Wednesday, 7 February 2001 10:41 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC]: LM335


Peter, I presume you've done that using a C compiler isn't it ?
If you have something in asm to share I would be interested...
Thank's Vasile


On Wed, 7 Feb 2001, Peter May wrote:

> Well what I do is my reff voltages are 0 and 5 volts. I store the analogue
> input into a word. I feed the word value to a computer and calculate the
> voltage from there. Multiply that by 1000 and then dived that by 10 gives
> you the degrees Kelvin. Take of 273.15 and that should give you degrees
> Celsius.
>
> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Vasile Surducan
> Sent: Wednesday, 7 February 2001 2:50 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [PIC]: LM335
>
>
> Thys, can you tell me how do you scale the output signal of LM35 to obtain
> full AD pic resolution and how do you convert for displaing celcius
> degrees. AT 0C LM35 output is about 2.7315V and depends of biasing
> current. At 100C will be about 3.73V For a 0..5V AD input, probably you
> need a diferential amplifier or for a pic16F877 to set -ref at 2.73 and
> +ref at 3.73 but in this case you will not have 10 bit AD resolution.
> Is there any more simple method to do that without external amplifiers
> and of course without any one wire or i2c temperature measurement devices.
> Thank's very much,
> Vasile
>
>
> On Wed, 7 Feb 2001, Thys Van Tonder wrote:
>
> > Hi there Peter
> >
> > The LM335 gives you 10mV/0K. So you better use shielded cable. I used
the
> > LM35 with about 4m
> > of cable and it worked fine for our application, a bit of switching
noise
> > from the motors we were probing. You can average out your reading in the
> > software.
> >
> > Regards
> > Thys
> >
> > -----Original Message-----
> > From: pic microcontroller discussion list
> > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Peter May
> > Sent: 07 February 2001 08:13
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: [PIC]: LM335
> > Importance: Low
> >
> >
> > I gave up on the DS18S20's and went to a simple LM335. It says in the
data
> > sheet I can run a long cable to it and use it remotely. In the finished
> > product it will be within a couple of inches of the PIC but for bench
> > testing I want about 20 feet of cable. Would this introduce much noise
> into
> > the analogue input?
> >
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