-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Could always just go with a Fluke type-K thermocouple immersion
probe.  Produces a milivolt/degree C or degree F output.  Scale it
with an opamp, and read with a PIC.  Not too tough.  Little bit pricy
though.  I think it would cost about $300USD for the set.  Though if
you're looking at TIG welding, it could also get that high,
considering the rates for professional welding...

- --Brendan

- ----- Original Message -----
From: "Spehro Pefhany" <speff@INTERLOG.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Wednesday, August 14, 2002 11:29 AM
Subject: Re: [PICLIST] [EE]:Measure liquids temperature with 18S20


> At 12:10 PM 8/14/02 +0000, you wrote:
> >Liquid is wine stored in tanks and the range of temp. is from 10
> >to 30 degrees.
>
> Be *very* sure that the closed end of the tube is made by TIG
> welding or some other NSF* approved (US/Canada standard) or
> equivalent method. In particular, you want to avoid cadmium-bearing
> Ag hard solders which will look nice, but leach out into the wine
> and cause contamination. The inert-gas welded probe is all just
> plain stainless steel and should last indefinitely under those
> conditions, unless damaged physically.
>
> For the heat transfer issue, silicone grease should work, and won't
> cause stress on the 18S20.
>
> Personally, I'd specify a proper industrial-quality Pt100 DIN RTD
> probe and either use a commercial signal conditioner or make one.
>
> * National Sanitary Foundation  http://www.nsf.org
>
> Best regards,
>
> Spehro Pefhany --"it's the network..."            "The Journey is
> the reward" speff@interlog.com             Info for manufacturers:
> http://www.trexon.com Embedded software/hardware/analog  Info for
> designers:  http://www.speff.com 9/11 United we Stand
>
> --
> http://www.piclist.com hint: To leave the PICList
> mailto:piclist-unsubscribe-request@mitvma.mit.edu
>

-----BEGIN PGP SIGNATURE-----
Version: PGPfreeware 6.5.8 for non-commercial use <http://www.pgp.com>

iQA/AwUBPVqk9gVk8xtQuK+BEQLU5QCfew/Q3pVKchNJWjgcdkLfqC0GclwAoJZX
GScsN7fpUHn4kX08fvxFa+hR
=5eaG
-----END PGP SIGNATURE-----

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu