Author Topic: For anyone having trouble in cold temps  (Read 629 times)

SuperDave

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For anyone having trouble in cold temps
« on: January 07, 2017, 01:37:49 PM »
I've read where a few of us have had trouble getting to set temps this Winter with the Auber.  For me, it was anywhere from 15 to 20 degrees short of set temp.  Last week I ran a cold weather auto tune and saw a range of 100 to 200 point differences in I and D values.  Today, it was 2 degrees outside ambient and the Auber locked in to set temp and has stayed locked in all morning.  The Auber has seemed to function quite differently for many of us with some, like myself, having struggled with it for the 2 years that I've owned it and those whom have never had a single problem.  In any event, if you are frustrated with the temp control in the Winter conditions, try an auto tune and see if you get the same swing in values.  In the short, it seems to have made a big difference for me in getting the desired temp setting. 

Model 4, Harrisville, Utah

noclue

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Re: For anyone having trouble in cold temps
« Reply #1 on: January 07, 2017, 02:13:54 PM »
I just recently purchased a 3D and on my first smoke it was overshooting temps by 20+ degrees, I just did a auto tune and my numbers are

P  76
I  212
D 303
I don't know if that's good, not sure what the numbers mean any insight would be appreciated.

LarryD

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Re: For anyone having trouble in cold temps
« Reply #2 on: January 07, 2017, 03:20:32 PM »
I just recently purchased a 3D and on my first smoke it was overshooting temps by 20+ degrees, I just did a auto tune and my numbers are

P  76
I  212
D 303
I don't know if that's good, not sure what the numbers mean any insight would be appreciated.

|Symbol|Description|Setting Range|Initial|Note
|P|Proportional Constant|0.1~99.9(%)|5.0|6
|I|Integral Time|2-1999(Sec)|100|7
|d|Derivative Time|0-399(Sec)|20|8

Note 6 Proportional Constant (P): P is also called the proportional band. Its unit is the percentage of the temperature range. e.g. For a K type thermocouple, the control range is 1500 C. P=5 means the proportional band is 75 C (1500x5%). Assuming the set temperature (SV) = 200. When integral, I, and derivative, d, actions are removed - the controller output power will change from 100% to 0% when temperature increases from 125 to 200 C. The smaller the P value is, the stronger action will be for the same temperature difference between SV and PV.

Note 7 Integral time (I): Brings the system up to the set value by adding to the output that is proportional to how far the process value (PV) is from the set value (SV) and how long it has been there. When I decreases, the response speed is faster but the system is less stable. When I increases, the respond speed is slower, but the system is more stable.

Note 8 Derivative time (d): Responds to the rate of PV change, so that the controller can compensate in advance before |SV-PV| gets too big. A larger number increases its action. Setting d-value too small or too large would decrease system stability, cause oscillation or even non-convergence.

Auto-Tuning
The Auto-tuning function (also called self tuning) can automatically optimize the PID parameters for the system. The auto-tuning function will use the On/ off mode to heat up the system until it passes the set point. Then let it cool down. It will repeat this about three times. Based on the response time of the system, the built-in artificial intelligence program will calculate and set the PID parameters for the controller. If your system has a very slow response, the auto-tuning could take a long time.

PV = Process Value = Measured Temperature
SV = Set Value = Set (Target) Temperature

Note:  I'm done modifying this post now.  :)  All of this information was taken from a document provided by Auber for their PIDs and is not my interpretation or personal knowledge.
« Last Edit: January 07, 2017, 03:40:40 PM by LarryD »
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LarryD

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Re: For anyone having trouble in cold temps
« Reply #3 on: January 07, 2017, 03:39:27 PM »
I wonder if pre-heating your digitial smokers with the PID turned off before beginning a smoke would make this a lot more reliable for you.  The job of the PID is to make small adjustments on a regular basis to achieve and maintain a target temperature.  Performing the auto-tune in the cold weather probably resets its 'P', 'I', and 'D' values so that it can overcome the super cold initial state, but I wouldn't be surprised if it means that it gives you a much more coarse/rough vs gradual/smooth temperature profile.

Please note... I'm just speculating here based on some reading and research just performed to make my prior post.  I'm a total novice with this and could just be wasting energy.  :)  (The info for the prior post was copied from Auber documents, so that should be pretty reliable.)
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SuperDave

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Re: For anyone having trouble in cold temps
« Reply #4 on: January 07, 2017, 03:41:16 PM »
noclue, others will undoubtedly have different opinions but I believe that the values are somewhat specific to your smoking conditions.  My results would say that someone auto tuning in Florida would get considerably different values than someone in Minnesota if both were done in the Winter time.  Some of the others here say that the values set in their controllers work all year.  The best thing you can do is throw a chicken in the smoker and do a test to see if you have improved your situation. 

Model 4, Harrisville, Utah

NDKoze

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Re: For anyone having trouble in cold temps
« Reply #5 on: January 07, 2017, 10:28:43 PM »
Nice job on your testing Dave! It sounds like you definitely may be on to something.

This may be even more important for those of us who live in areas that have such a huge range of ambient temps that we smoke in.
Gregg - Fargo, ND
Smokin-It #3 that has now replaced the Masterbuilt XL and 10+ Year-Old Big Chief. I also have a Weber Genesis Gas Grill, Weber Little Smokey at home and a Chargriller Deluxe (stick burner) and Camp Chef Three Burner Stove with Grill/Griddle out at the lake place.

noclue

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Re: For anyone having trouble in cold temps
« Reply #6 on: January 09, 2017, 05:51:44 PM »
noclue, others will undoubtedly have different opinions but I believe that the values are somewhat specific to your smoking conditions.  My results would say that someone auto tuning in Florida would get considerably different values than someone in Minnesota if both were done in the Winter time.  Some of the others here say that the values set in their controllers work all year.  The best thing you can do is throw a chicken in the smoker and do a test to see if you have improved your situation.
Thanks for the response, tried mine out Saturday and worked much better than the first time. I am thoroughly enjoying the knowledge on this forum, and the lack of annoyance from everybody when I ask a question that I know was asked before but I'm having trouble locating using the search.