They have all of the finer mesh that you are looking for in stock and ready to ship, I just bought a small piece of copper from them, and was very satisfied with the product.
Hi Dana (or anyone else who has implemented this type of P1 mod),
I am building out a unit with Auber components close to those specified in your original proposal. I have a 3 amp Variac to control fan speed so the final rig should be very similar to yours from a functional standpoint. I am curious what your roasting profile looks like now that you have had a bit of experience with the machine. I see lots of detailed profiles for drum based roasters but few for fluid bed and almost none specific to a modified P1. In particular I'm looking the progression you use for programming your PID. Ramp to x degrees F in y minutes, hold for z minutes, ramp ... etc. As it stands now, I'll be using the TC at the air inlet (MET) for programming purposes. Any suggestions will be appreciated.
My roaster is out of commission since I moved at the beginning of the year, and I can't remember the ramp profile that I programmed into the PID. Sorry. If/when I get it back into commission I'll post here.
Dana
Dana Leighton - Espresso hack and CoffeeGeek moderator
I can give you a simple recipe to get you started in the right direction. Using the MET probe temps:
Preheat the roaster to 325F (300 to 350F max range) Hold 325F for first 1-2 minutes of the roast. Then Ramp MET at 25-30F per minute until 450-460F. Hold 450-460F until roast completion.
If you are using a Bean Temp probe, this would help to respond to different beans so you might roast a tiny peaberry different than a Pacamara:
After the initial drying at 325F, always keep MET temps about 60-80F ahead of Bean Temps for the ramp phase to 450-460F. Check BT rate of rise: 25-33F per minute is a good range to work.
Another rule of thumb: I look for 3-4 minutes for each phase of the roast; Drying(to 300F BT), Ramp to First Crack, and Finish, for a total roast time of 9-12 minutes. Faster for more lively, slower for more mellow.
edcurry Senior Member Joined: 27 Sep 2012 Posts: 3 Location: ATL Expertise: I love coffee
Espresso: Rancilio Silvia with Auber... Grinder: Baratza Vario Drip: Braun 3116 Roaster: Modified PI with PID
Posted Sat Oct 13, 2012, 8:48am Subject: Re: (Another) Poppery PID controller project
Thanks guys.
Dana, in an earlier post in this thread there is a link to your supply spreadsheet. It is now 404. Could you post that inline? I've figured out that the Auber PID I bought is either junk or not up to the task. Fuji is a bit too proud of their controllers so it looks like I'm going to give the Delta a try.
Second question: has anyone built out a controller using variable output voltage and and an SCR? I'm not finding a reasonably priced SCR. I'm guessing this would be total overkill for this if you guys are seeing input temperatures stable with a few degrees swing using pulse and SSR. I'm swinging in a 100 degree range with the Auber. I think it is built for much slower systems.
OK I am trying to load it here. Excel is not listed as a supported file type, but lets see what happens.
I'm swinging in a 100 degree range with the Auber. I think it is built for much slower systems.
I would tend to think the swing is because of the P, I and D parameters you've got in the PID unit. Have you tried autotuning the PID? I did my autotune when the beans were at first crack temperature, then I adjusted the parameters slightly to reduce the swing.
edcurry Senior Member Joined: 27 Sep 2012 Posts: 3 Location: ATL Expertise: I love coffee
Espresso: Rancilio Silvia with Auber... Grinder: Baratza Vario Drip: Braun 3116 Roaster: Modified PI with PID
Posted Sat Oct 13, 2012, 6:19pm Subject: Re: (Another) Poppery PID controller project
Thanks Dana, that file doesn't seem to have valid contents. Not a big deal I was just trying to figure out what you type of interface was needed to access the controller via serial or usb.
As for settings on the PID, I have tried its auto-tune several times and various manual adjustments. I think the design of the unit I am using is simply too slow for this application. Replacing it with one that I know will work won't break me.
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