More on the PID

Started by Patience, April 29, 2007, 07:39:02 PM

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Patience

After pouring over all the PID posts, I still have one question I need clarification on.  It seems everybody talks about autotuning for one temperature (being their favorite temp for most of their fixin's) however, I have only found a few threads indicating people being able to keep the kind of control with the PID over say, 3 different temps over a single smoke. 

For example, some of the cured summer sausage I have done requires 2 hours at 130 deg, 2 hours at 150 degrees, then a final cook at 170 until done.  My questions are, what temp would I autotune for this process and, will it keep the same constant temp around a set temp of 130 as it would at 170 even though it may not be autotuned for these temps?

I was under the impression I could run out in just my underwear and big rubber boots this winter (as so often the occasion) to change water and press the up button on the PID to a new set temp. Currently I have to wake up an hour after each slider change to check the Maverick.  Apparently the author of this recipe says these temps are a must for the ingredients used, but its a real challenge with the slider to control temps that tight.  If I could hold +/- 3 deg. with a PID like most are reporting, but at EACH temp I might even skip the rubber boots this winter!

Thanks in advance for any input.

Have, Patience.
A well used minimum suffices for everything -- Phileas Fogg

Mr Walleye

Hi Patience and welcome to the forum.

I did the auto tune with a butt in set at 210. I do see a little more varience in temps when doing things like jerky at say 170 degrees. The one thing I've thought about is if I record the P I and D settings then ran auto tune again at say, 160 degrees, I would probably end up with slightly different numbers. This way you could manually set the numbers, which is easy, depending on the temp range you are wanting. Currently I am +/- 1 degree in my usual temp zone of 200 to 220.

Mike

Click On The Smoker For Our Time Tested And Proven Recipes


Arcs_n_Sparks

Patience,

Welcome to the forum. I do not have an autotune PID; I've built one from scratch and have manually dialed in the parameters. With that said, allow me to ramble....   :o

Since low temperatures can be obtained by the puck burner alone, and you do not control that, I would not tune with low setpoints. You are interested in optimizing the part you can control, and that is higher temperatures.

Another challenge (although I have not experimented with this) is that I believe the overall system response is tied to vent position. The thermal pathways through the sides of the box are fixed, but the vent represents a significant thermal pathway that can vary quite a bit. That complicates the PID control loop. Now, in the overall scheme of things, probably not a big deal. However, I figure I should probably investigate this for the next 10 years while sipping adult beverages....  :D :D :D

Arcs_n_Sparks

Mr Walleye

Hi Arcs

I still have a plan to semi-permanently mount my generator in a separate box. By doing this the heat plate on the generator would have less influence on the tower temp. At least thats the plan.

Gotta agree with you... more study is required! Better stock the beer fridge!  ;D

Mike

Click On The Smoker For Our Time Tested And Proven Recipes


Gizmo

Mr Walleye, I thought for sure your next few words after "plan to semi-permanently mount" was going to be "Kegerator".   ;D
Click here for our time proven and tested recipes - http://www.susanminor.org/

Arcs_n_Sparks


Mr Walleye

Hmmmm!  :D  :D  ;D

Mike

Click On The Smoker For Our Time Tested And Proven Recipes


bunnydude

What in plain english is a PID and is it neccesary and are they easy to come by?
While I am here explane FTC please. :P

Mr Walleye

#8
Hi BD

Here is  link to the PID plans on Old's recipe site http://www.susanminor.org/forums/showthread.php?p=504#post504

The PID is an acurate temp control for the BS. Gives more of a set and forget setting that is usually + or - 1 or 2 degrees. There is a ton of posts on a number of variations but most are similar to the link above.

Mike

Click On The Smoker For Our Time Tested And Proven Recipes


Arcs_n_Sparks

Quote from: bunnydude on April 29, 2007, 08:58:52 PM
What in plain english is a PID and is it neccesary and are they easy to come by?
While I am here explane FTC please. :P

Bunnydude,

Welcome to the forum. The PID is your Porter Indicating Device. It tells you where your beer is. Some have morphed this to be a Proportional, Integral, Derivative controller. This appears to be some E.E. invention to control your BS temperature. I built one, but still depend upon my adult beverage refrigerator for superior temperature control.

FTC is either: Follow The Chicks or Fill The Cup; depending upon your PID settings. Others will claim it means something like: Foil, Towel, Cooler (now that will make you drink). The theory here is to put your smoked gem in foil, wrap in a towel, and place in a cooler to further cook and/or remain at temperture until you have finished your beers and are ready for dinner.

At this point, more professionals will weigh in.......   :D

Arcs_n_Sparks

coyote

Words to live by Sparkler :) ;) ;D



Coyote

Habanero Smoker

Patience;
Welcome to the forum.

I don't know what type of sausage you are making, or how thick they are, but I found that using Jaeger's method of hot smoking sausage works well in the BS.

I modified the temperatures a bit lower. The temperature within the parenthesis are his. Preheat the smoker to 140°F (145°F). Place sausage in smoker, with vent wide open; dry the sausage for about 30 minutes. Close vent to 1/8 opening and apply smoke at this temperature for 2 hours. Next increase the cabinet temperature to 180°F (190°F), and if possible rotate sausage, at this time. I rotated the sausage one more time when the sausage comes within 10°F of the targeted internal temperature.



     I
         don't
                   inhale.
  ::)

Patience

So basically, its harder to control the lower temps (just as I have found manually with the slider) but a PID would work better than the slider anyhow, though may not be +/- 3 deg. which I would love to get. 

I did get an email from Auber within an hour of emailing on a Sunday night, now THATS impressive!  I asked about the PID w/ramp and soak that you can program upto 30 different actions.  I would be able to set as many temps and hold for as many hours making the process even more automatic.  Thats too tempting! 

I am trying to eliminate as many variables as possible including the venting.  Putting the smoker in its own cabinet would cut out the wind and draft fluctuation I think thats a good start.  Bottom line, just using the BS with no mods midwinter in a snow storm worked awesome.  But, the grass is always greener so they say. Some babysitting is still required with a plain jayne OBS, but thats relative when you think about charcoal or wood fired smokers. 

Have, Patience
A well used minimum suffices for everything -- Phileas Fogg

West Coast Kansan

Patience, welcome your PID questions and grass is always greener observation fits well with a significant number of the - just one more modification and I can make this smoker even better crowd here - I have not yet joined the mod squad but am sure it is just a matter of time.  ;D  ;D  ;D

One question,  ;) is it necessary to wear underwear if you are consuming adult beverage from a rubber boot and it is not winter time  :)  :)   :)

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NOW THAT'S A SMOKED OYSTER (and some scallops)

Mr Walleye


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