Okay, I'm listening.  This is what I'm looking for.  So the oven's=20
controller is completely bypassed and/or removed, and the PID controller=20
just PWM's the heater coil on/off?

Even heating is critical.  I checked ovens at the local walmart a couple=20
days ago and all the convection options get poor reviews, with lots of=20
remarks about uneven heating.  Larger should be more even, as well as=20
convection.  I'll to check some higher-end stores to see if there are=20
better options, otherwise I can get commercial convection ovens on=20
Ebay.  I do have a bunch of thermocouples on hand, so I may be able to=20
set these up on a blank PCB panel and test the oven first.

Setting the profile is no problem.  I had to do that with my conveyor=20
oven, and yes the profiles in the component datasheets are great=20
starting points.

Would be nice though if I could buy this ready to go.  I know there's a=20
TWS brand like this, but they're pricey.

Cheers,
-Neil.



On 7/20/2012 4:41 PM, Jonathan Hallameyer wrote:
> With a budget of $500, an omega PID controller  (i.e.  CN4416-DC1-R2 )
> And an appropriate SSR, some thermocouple wire (dont bother with
> extension wire, omega has plain thermocouple wire available in short
> lengths, but not extension wire) , a welded thermocouple (since
> obviously you'll melt it if you solder your own),  thermocouple
> connectors  and misc terminals/lugs to wire up the the thing and you
> can have a nicely controlled oven.   No suggestion on ovens, but
> something with a big area and a convection fan may be a good starting
> point.   No suggestion on settings either, but given its a ramp/soak
> controller, I'd start off putting in a suggested profile from a chip
> maker.
>
> I used the omega CN4116-DC1-R2 (iirc) and some 20A SSRs in a control
> cabinet I put together for for my pet snakes heat-mat and a timer for
> day/evening lights. The heater is only ~60W and the lights 100W
> http://i6.photobucket.com/albums/y204/CKOD/8a4268e7.jpg  SSRs are too
> close, but  I doubt it will be a problem with their current load. (yay
> overkill)
>
>
> With the autotune, there no fiddling with PID tuning, just run the
> oven empty with a set point around what your max will be, jsut let it
> run and it'll finish up after a few heat/cool cycles, and save the
> settings.


--=20
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