For a two chip analog solution, why not the Linear Technology LT1025 -
cold compensation, and separate inputs for type J, K or T and R or S.
Digikey has it for $6 Can. To amplify add a LTC1052 chopper amp ($10 C).
Go to:
http://www.dtweed.com/circuitcellar/caj00031.htmand look at the PDF for "Temperature Monitoring" by Steve Ciarcia.
Grant
--- In
Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@...> wrote:
>
> On Thu, 24 Aug 2006 14:48:12 +0200, Herbert E. Plett <cachureos@...>
> wrote:
>
> >
> > why so much complication?
> > hardware is dead simple using a 1-wire interface from Dallas-Maxim.
> > thermocouple feeds directly into an ADC (DS2761) that directly
digitizes
> > with a
> > resolution of 15uV, measures digitally its own temperature and
connects
> > to a uP
> > via one pin (and ground). also has a 2-5V ADC that can be fed
directly
> > from a
> > pot (ie, setpoint).
> > so, all is needed is this chip
> > ( http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3468 ) plus a
microP (I
> > use
> > Atmel Tiny), plus an opto-triac/triac pair or a solid state relay
and a
> > few
> > passives, switches and a pot with a large knob.
> > the process is all digital and the micro has the chance
(responsibility)
> > to
> > implement whatever algorithm fits (from on-off to self adjusting)
plus
> > any
> > bells and whistles (LCD display, serial logging, profile, etc).
> > BTW, it DOES fit on a 1" x 2" board (exclusive of power and relay).
> > I kept following this discussion in the hope somebody would come
up with
> > a two
> > chip reasonable analog solution, but no, no such... (at least yet)
>
>
> I bet you can't do it under 20eur either...
>
> ST
>