Author Topic: Dual PID auto tune necessary after mod?  (Read 2510 times)

Offline ghosttown

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Dual PID auto tune necessary after mod?
« on: December 23, 2015, 05:12:40 pm »
Been running the 900watt mod with the dual PID Auber without any issues, however I am wondering if people that does have either the second 500watt element or the 900watt if they did an auto tune again on the PID Controller? The PID does come pre-configured for the Bradley but that is setup for a single 500watt element. Is there a reason to auto tune and if so how did people find it with the new values?

Offline beefmann

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Re: Dual PID auto tune necessary after mod?
« Reply #1 on: December 23, 2015, 05:35:30 pm »
i have a  custom mad pid controller andhad to  auto tune for my 900 watt element,, ,if yours has  not been tuned for your set up,, you  should auto tune it
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Offline ghosttown

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Re: Dual PID auto tune necessary after mod?
« Reply #2 on: December 23, 2015, 05:38:23 pm »
I figured that as it came pre-configured for the bradley 500watt element and now I have the 900 watt. I assume the smoker needs to be cool down? Reason for asking I am just about done smoking something, can I do the auto tune while it is warm?

Offline TedEbear

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Re: Dual PID auto tune necessary after mod?
« Reply #3 on: December 23, 2015, 05:58:25 pm »
As I mentioned in the other thread that you posted on this, they say to change the P value to 14 from 7 for dual 500W elements.  Since you're running a 900W configuration, the ideal value would be 12.6.  I'd set it at 13 and also do an autotune.  Don't forget to place a couple of bricks or something in the smoker to simulate  a load of meat.

500 / 7 = 71.4

1000 / 14 = 71.4

900 / 71.4 = 12.6  (that's how I arrived at the above value)  :)




Offline ghosttown

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Re: Dual PID auto tune necessary after mod?
« Reply #4 on: December 23, 2015, 06:06:43 pm »
As I mentioned in the other thread that you posted on this, they say to change the P value to 14 from 7 for dual 500W elements.  Since you're running a 900W configuration, the ideal value would be 12.6.  I'd set it at 13 and also do an autotune.  Don't forget to place a couple of bricks or something in the smoker to simulate  a load of meat.

500 / 7 = 71.4

1000 / 14 = 71.4

900 / 71.4 = 12.6  (that's how I arrived at the above value)  :)

For some reason I forgot about that post, did you find when setting it to 13 and then doing an autotune that other values also changed? Actually put bricks in the smoker really :).  Did the new values help you at all?

Offline TedEbear

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Re: Dual PID auto tune necessary after mod?
« Reply #5 on: December 24, 2015, 08:27:31 am »
For some reason I forgot about that post, did you find when setting it to 13 and then doing an autotune that other values also changed? Actually put bricks in the smoker really :).  Did the new values help you at all?

I don't have the plug and play version.  My PID (Auber SYL-2352) is built into the SG.  All I know that from reading other threads on here Auber says to change the "P" value to 14 from 7 if you add a second element and double the cooking wattage. 

I'm not sure what values would be changed if you ran the autotune but you could look at the settings afterwards and check to see what the P value is.  I guess you could just try changing the P value and see if it maintains a stable temp with a load in the Bradley prior to doing anything else.  If it does then I'd leave the rest alone.



Offline ghosttown

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Re: Dual PID auto tune necessary after mod?
« Reply #6 on: December 25, 2015, 07:22:33 am »
I ended up changing the p value to 14 and then doing auto tune, couple of values changed but the p value is now 144. I read you divide that number by .1 to give you the p value but the factory setting was 7. Should I leave it to 144 or 14?

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Offline TedEbear

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Re: Dual PID auto tune necessary after mod?
« Reply #7 on: December 25, 2015, 10:30:54 am »
I guess you could test it out at those settings and see if it holds a tight temp.  If so, I'd leave everything the way it is.

Offline ghosttown

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Re: Dual PID auto tune necessary after mod?
« Reply #8 on: December 25, 2015, 10:37:58 am »
I guess you could test it out at those settings and see if it holds a tight temp.  If so, I'd leave everything the way it is.
I am redoing the auto tune now to see what the new result is. But I am wondering if the p value should be 13 if 7 is for an 500 watt, why did it give me such a high number?

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Offline ghosttown

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Re: Dual PID auto tune necessary after mod?
« Reply #9 on: December 25, 2015, 10:48:57 am »
This is my new value, it seems way off then the original setting which is okay because of the 900 watt mod I did but the p value is not 13, is that okay?

P  - 61
I - 326
D - 81
At - 0
T - 2
R1 - 1
R2 - 0

How can I validate these  settings are good, if the cabinet rises to the set temp and if it holds its there?

Also want to include that the smoker is well insulated with an encloser

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Offline TedEbear

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Re: Dual PID auto tune necessary after mod?
« Reply #10 on: December 25, 2015, 09:09:03 pm »
How can I validate these  settings are good, if the cabinet rises to the set temp and if it holds its there?

That's how I would do it.  Run a test with a load in the chamber and see if it maintains the temp within a few degrees of your setpoint.  I don't know why the autotune P value is so different than what Auber recommends but if it works I'd keep it there.

Near the end of the article in the link below it talks about some of the different values of the PID controller and what they mean, if you want to tweak a few things.

Auber Plug & Play PIDs - Single/Dual Probes

Offline ghosttown

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Re: Dual PID auto tune necessary after mod?
« Reply #11 on: December 26, 2015, 04:56:52 pm »
Agree, not sure why its so different. I sent Auber an email to see what they say about the values, I am running auto tune when the smoker is completed cold but I did see somewhere you should bring the smoker up to the set temperature and then run auto tune then. Not sure if that is correct.

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Offline GusRobin

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Re: Dual PID auto tune necessary after mod?
« Reply #12 on: December 26, 2015, 07:06:35 pm »
Why not just run the autotune? You can cook while you autotune. When I have autotuned I have done it when I was cooking a 8 # butt rather than using a brick or something. That way you get a better reading and it doesn't impact the cook at all. For a while the lights flash more often but after a couple of hours it completes the autotune and the lights go back to "normal".
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Offline ghosttown

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Re: Dual PID auto tune necessary after mod?
« Reply #13 on: January 10, 2016, 10:34:04 am »
I deiced the auto tune settings were not the greatest compare to the default settings it came with,  so what I did was I changed everything back and only changed to the P value from 7 to 13 as I do have the 900 watt element.

I set the cycle to run for 3hrs @ 240F, the temp raised to 215ish pretty fast within 10mins however it took about 35-40mins to rise to the set temperature of 240. The out light did start flashing around the 200-215 mark indicating it is not providing full power to the element which I understand that is normal because it was not giving 100% power, however it took a long time to reach the set temperature because of that. Should I play with the P value to fix that, or is that normal behavior?

Also when the probe temperature stated it was at 215, both of my maverick probes where about 15F more and indicating it was at 240F the set temperature. Both probes were in the cabinet and both were installed near the Auber Probe. Can it be that the probe for the Auber is defective if both of my maverick probes had the same reading and both probes were put on the same rack as the auber probe?

Thanks

Offline mturcotte

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Re: Dual PID auto tune necessary after mod?
« Reply #14 on: June 30, 2017, 12:25:26 pm »
Old thread here but I just updated my OBS with a 900w element and added a fan at the same time.

I ran the auto tune and my numbers are
P:76
I:341
D:85

I can't say if these settings are the best but I just smoked 12 pounds of salmon with those settings, it took at least 30% less time than with the standard element.

ghosttown, what did you end up doing with your parameters?