Temperature Controller Question

Michael J. Spangler

Michael J. Spangler

Joined
Oct 8, 2003
Messages
2,181
alright guys. i check out the how to make a HT oven thread on britishblades http://www.britishblades.com/home/articles.php?action=show&showarticle=31
and this seems way to good and easy to not do.

but i would say it isn't worth having it unless its digitally controlled right? so i need some info on controllers, anyone know some basic terminology? like what the heck does DIN mean?

either way i was looking into the controllers under the ramp/soak section on omega.com
http://www.omega.com/vh/subsectionVH.html?subsection=A04&book=vhPC

so what do you guys think? i would be using the elements from budget casting supply as listed on the tutorial.

is there anything else i'm not taking into consideration? other than a thermocouple? thanks a lot in advance guys

:thumbup:
 
Michael,

look for my posts on this subject - I've explained most of what
one needs to know about it.


Not much to it, not expensive either.

About DIN - it has to do with the controller's form factor. For an oven you make yourself it doesn't
matter much. But, if you want to install something so it fit standard size openings, this is where DIN
sizes come in. Like, say, stereo system fitting car dash.
 
Mike, this rocks. Thanks for posting.z I was just complaining to J tonight about my toaster oven and not being able to regulate it accurately enough for my tastes. Any estimate on what this project would cost?
By the way, did you ever get that Helve hammer up and running. I have a line on a BIG canvas belt, the kind farmers use to run a buzz saw off of the PTO on their tractors. Its about 6" wide and 1/4" thick. I believe its new never been used. Something you could use? Let me know and I'll bring it to one of the hammer ins.
Ed
 
thats Ed, i don't have it done yet, it is moving and all freed up but i need a mottor a beam and a belt. maybe you can get it to the next hammer-in. or ashokan.

hey will you make it to the NECKA hammer-in on may 26th?
i figure on the high end if you need to buy everything and don't have good sources maybe 400 bucks for the whole thing.

rashid thanks again man i appreciate it. i'm gonna see if i can sell a knife and get the damn thing together soon! now if i could just sell one of my knives:(
 
alright so i need a controller a relay and a thermocouple. in addition to the stuff listed on the tutorial.

so help me out here. i'd love to sit and learn about how it all actually works but i don't think i have the time or room in my cluttered head.

out of the page i linked to, what would you use for a controller?
seems the 7500 or the 7800 serries are a good deal, and 8 programs with 8 functions each is plenty for what i need to do.
then a k type thermocouple, it seems there are a lot of thermocouple st ups there, what should i look for?
and last but not least what type of SSR will work with this?
thanks man. i tried reading some but theres too many options with electronics, i'd just prefer a professional such as yourself give me the write answerrs before i blow something up. thanks man!:thumbup:

i guess i could just call someone at omega and have them answer my questions instead of buggin you man. thanks again
 
Hi
I built that oven . I made mine with an 18 inch interior 5 wide by 4.5 high.
I would reccomend welding or brazing the frame rather than rivets. I made mine with a removable top in case i need to repair anything. I used the non rampable control from Auber Inst.Once you understand the tech talk it's not to hard to program. Holds temp within 1-3 degrees. Hits 1500 in 10 minutes.
Hope this helps. Had 300$ in it.
TJ
 
Mike,
I built my own controller setup myself,
I think the controller is a 7600 from Omega, I'll check tomorrow.
If I remember right my controller setup cost around $400 by itself and that was 5 or 6 years ago. Maybe the prices have come down a bit. I think I have part #'s for all the stuff I got around here somewhere, I'll check.
I usually get the 12" type K thermocouple, but the size is really up to you.
More later,
Del
 
re-re-re-explaining DYI HTO is me fate, it seems . Oh well :)

- on SSR: get one that will support 25A:
http://cgi.ebay.com/New-25A-SSR-Sol...ryZ78207QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

$7 or so

- on controller:
this will work http://cgi.ebay.com/Dual-Digital-F-...hZ015QQcategoryZ50926QQtcZphotoQQcmdZViewItem

$50 or so. You can get one for $30, if money is real tight, just browse Ebay looking for similar item

- on TC: you want "K-type, shielded" thermocouple , good to ~2200F

Something like this one (it is in a kit, might as well buy the kit :):
http://cgi.ebay.com/Kiln-Temperatur...1QQihZ015QQcategoryZ42897QQrdZ1QQcmdZViewItem

Make sure it is rated to that temperature - it usually means it will have ceramic or inconel exterior shield.

- on heating element: use ONLY Kanthal A1, 17 or 16 gage, nuff wire to get
you say 15 Ohms of resistance for 240V . I wind my own, using a lathe I have. I chuck up a long piece of 3/8" or 1/2" round stock, supported by dead
center in TS and at looooow RPMs, carefully, wind it up. Make sure the wire doesn't twist up on you, into a "knot", as you do that.

Please note that I do it on a lathe that I HEAVILY modified - and it can go as low as 30RPMs. If one is not careful, you may have
your hand caught up in the wire and "wound up" onto the rod, along with wire. You don't want that so be very careful. EZ does it.


I earlier advised to run the spiral @ 20A. I now recommend a lower current, say ~15A instead - it makes the oven a bit slower but the spiral will last much longer :)
 
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