PID calibration

GBIceman · May 11, 2011, 08:20:38 PM

I have been using the dual probe auber with great success. I have just added the second heating element with the on/off switch. Tried out the new setup and was not impressed with the temp. Discovered one of the heating element was burnt out. (original heater element from DEC 2010) Replaced with heater from yard and pool. Both heaters now from yard and pool. One more advantage of the two heater set up, if one goes out you still have one available till you get a replacement. I am going to try two 4# butts this weekend, do I need to recalibrate the Auber for it to work properly with the two heaters?

GusRobin · May 11, 2011, 08:29:23 PM

I have dual elements and have used my dual probe PID with the original settings for a while now and it runs good. You can autotune or just follow Auber's direction.
Per Auber "For the Bradley smoker with second heating element, we have done some tuning. The only parameter you need to change is the P value. It should be increased from 70 to 140. The rest of parameters should be kept the same as the original (I=600 and d=150). This will give you the best result."

muebe · May 11, 2011, 10:12:26 PM

I wonder if that setting would work ok with my 900W finned element...

GusRobin · May 12, 2011, 06:18:13 AM

Quote from: muebe on May 11, 2011, 10:12:26 PM
I wonder if that setting would work ok with my 900W finned element...

If it were me I would autotune. The Auber suggested settings are based upon testing with a Bradley OBS. As with everything " your mileage may vary". I would assume the variation between bradleys with the dual elements would be minimal. Not sure what the variation with the 900 fin heater would be. Autotune is relatively simple to run. If you do run it you may want to post the results for the other "finners" to use.

muebe · May 12, 2011, 07:26:36 AM

Quote from: GusRobin on May 12, 2011, 06:18:13 AM
Quote from: muebe on May 11, 2011, 10:12:26 PM
I wonder if that setting would work ok with my 900W finned element...
If it were me I would autotune. The Auber suggested settings are based upon testing with a Bradley OBS. As with everything " your mileage may vary". I would assume the variation between bradleys with the dual elements would be minimal. Not sure what the variation with the 900 fin heater would be. Autotune is relatively simple to run. If you do run it you may want to post the results for the other "finners" to use.

Thanks Gus...

Do you think I should autotune with the convection fan on or off???

GusRobin · May 12, 2011, 04:51:18 PM

I would autotune with what you would normally use. I maybe would even throw a chicken in there ;D

muebe · May 12, 2011, 04:56:46 PM

Quote from: GusRobin on May 12, 2011, 04:51:18 PM
I would autotune with what you would normally use. I maybe would even throw a chicken in there ;D

I am going to do it with the fan on :D So place all the racks in it, water bowl with water and maybe a couple bricks to simulate a load and then run the auto tune?

GusRobin · May 12, 2011, 04:57:37 PM

yes

Habanero Smoker · May 13, 2011, 02:22:56 AM

About 3 pounds of sterilized sand, and a quart of water in a foil pan is a pretty good substitute for about 5 pounds of meat.

muebe · May 13, 2011, 07:03:18 AM

Well I ran the PID auto-tune last night with all the racks in, a tray of water, convection fan on, temp probe at the middle of the cabinet and two cold red bricks to simulate a load. I think I am ready for that 14lb butt now. I am going to put the butt in tonight after I get off work around 10PM for a overnight smoke. This will be the major test for my new element and fan mod. I will be smoking it at 220F with the convection on after 4 hours of smoke. I was thinking it should be done close to 4pm on Saturday(18 hours) but with the convection fan on I think it will be done much earlier...