diy pid controller

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sparks65

Fire Starter
Original poster
Jan 15, 2017
49
57
Morning all.  First time poster, long time lurker.  I hope this is the right spot for this.

I recently built a pid controller for my Primo XL. Pretty much every thing came from Amazon.ca  After a coulee of test runs it seems to work "ok" but not great.  

I know very little about the setting up portion of a pid.

 I was hoping that if some one else has done the same thing they might share their settings.

Currently  I'm set as follows.

P :70

I  :600

D:150

Thank you for your time.
 
Have you tried to run an AUTO TUNE to train the PID?  That will let the program "read" your actual pit and what it takes for your heating element to hold the set temperature  This will likely give the best profile for your smoker.   I would use the auto tune settings as a baseline, and make tweaks from there if you feel its needed. One the auto tune process is complete you should be able to manually step through the settings on the PID and see what the software decided was the best setting for your pit (write it down and save it). Generally an auto tune get the job done and can be left alone.

You did not say which PID you have, but the main one on Amazon is the MYPIN TA4.  Also it seems there are a wide range of schematics and internal settings on the ones that are on Amazon and eBay.  I would double check the schematic drawing on the actual PID and make sure that is how yours is wired to the pit and SSR, and then run an auto tune for the above stated reason.

How to Auto Tune a MYPIN TA4
  1. Auto tuning can be done repeatedly, it does not harm the unit.
  2. With PID set up to run and the unit on....
  3. Set the desired temperature that you will be smoking at
  4. Press and  HOLD "AT" for at least 3 seconds until the "AT" LED lights
  5. When the "AT" LED goes out, the unit is trained for your pit at the selected temperature.
  6. Step through the settings manually and write down what they are after the auto tune.
  7. Tweak if necessary (usually not).
Let us know if that helps....

---------------------------------------------------------------------------------------

Edit...

I have not tried a PID to control a fan for a charcoal smoker like a home made version of the BBQ GURU.  When I wrote the above, I'm thinking a PID controlling a SSR for an electric element.  In theory the process would be the same, but there will be some differences as power to an electric element gives pretty much instant heat, and air to stoke the coals has a more sweeping rise in temp, potential for overshoot, and gradual cool down after the air flow is stopped.  The main issue with charcoal is there are variables that change as the fuel is consumed, where an electric element is a constant. I know there have been people who made their own GURU's, but from what I have read, there are varying levels of success due to temp swings. 

Before running the auto tune, I would get the Primo XL up to the desired temp manually, then run the auto tune cycle and let the PID & fan try and determine the best settings.  That is they way I use my BBQ GURU.  I get the pit up to the 220-235* range, toss on the meat and let the GURU take over.  But again, I've not tried a home made PID setup on a fan to stoke a charcoal pit before.
 
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Auber apparently has issued some guidelines for the initial PID settings when their units are used with fans in charcoal pits.  Auber recommends these values P=1.2, I=300, d=70, SouF=0.7. SouF is not a setting in a MYPIN, but it appears that Hysteresis settings would be the MYPIN version (not sure if the value is a direct translation though).

I did find quite a few of these that people have made for charcoal smokers in a google search.  Most seem to report that the auto tune will get the job done.   Here is one page with a good bit of info on one that a fellow in the UK made for his UDS:

http://ukbbqreview.com/bbq-accesory-reviews/build-digital-forced-draft-smoker-controller/
 
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Dward51. Thank you for the tips and ideas1.  defiantly going to try that AT feature.  As an after thought I bought a Inkbird PID off amazon.ca.

 I bought this particular one  1) they had an actual web site. (and so far they're after sales service has been pretty good)

                                              2) I could get this PID to read Fahrenheit.  After all this time I still cook in F. 

CrankyBuzzard.  Not to sure whatcha mean by that?
 
What brand/model is the one you have?  If it's a MYPIN, they can be toggled between C and F readings in the setup menu (most PID's can).
 
Dward.  It's an Inkbird ITC-106.  It was kind a toss up between the Inkbird and Mypin....I guess I liked the thought of a real web site.  As i mentioned the one or two questions I had were answered quickly and fairly accurately.    Smoking' a 4.5 lb. Butt tomorrow and am looking forward to trying your suggestions.  Pics to follow . 
 
Did you ever figure out the setting? I just made one out of an itc-106 myself and I haven't had time to use it yet to figure it out much.
 
Damn sorry ITW, I just noticed your post re: the pid controller.  I found if you bring your pit slowly up to the desired temp with the PID set to auto tune and with the fan disconnected it worked out not to bad.  Now I'm having probe temp issues in that my Maveric ET 733 says one temp and the PID probe reads 50/60° different.  Haven't figured that one out yet.

Mark
 
Damn sorry ITW, I just noticed your post re: the pid controller.  I found if you bring your pit slowly up to the desired temp with the PID set to auto tune and with the fan disconnected it worked out not to bad.  Now I'm having probe temp issues in that my Maveric ET 733 says one temp and the PID probe reads 50/60° different.  Haven't figured that one out yet.

Mark
 
Most PID units have an "offset" function that can be changed in the setup menu.  I have seen PID units that were previously used that had a lot of the internal settings changed from the default.  I would start by:

1) verify both the PID sensor and Maverick readings in boiling water.  See which unit is correct and which is wrong.

2) Also make sure the PID sensor type being used is correctly programmed in the setup (ie, a K type sensor set as a K type in the PID menu, etc....).  Most PID's are set for K type by default.

3) If PID is way off in boiling water and sensor type is set correctly, check the setup menu to make sure the values are not wrong for the various parameters. Look for the offset value field (may have a different name, but most PID's have this option).  If the offset is 0 and you are still getting wrong readings on the PID, try to use the offset to correct it (ie, if PID is reading 50* high, set offset to -50*) then recheck against boiling water.

I bet you will find the problem is the sensor type setting.
 
Greetings all. I am new to the forum, but came across this thread while trying to set up an Inkbird PID controller for my smokers. I couldn't get it set right after much effort, so I built my own controller that I can monitor and control with a mobile device. I have had excellent results with my DIY controller. I built an excel spreadsheet that I use for measuring a pit or electric smoker. It is very simple to use, and I have zipped and attached it FYI with some data and settings.

  1. Simply start taking temp readings every minute.
  2. Hit full power (or full fan or full open damper) after a few minutes and keep measuring by the minute. Try to be accurate on time intervals. After the temperature rise rate stabilizes and is increasing the same amount each minute, take a few more minutes of readings. Spreadsheet shows Command = 100%.
  3. Then cut the power (or stop the fan or close the damper). Note the minutes when you cut power or close the damper. 4. Keep taking measurements every minute. Make sure you keep taking measurements until some time after the fall rate stabilizes and is dropping the same amount every minute. Take a few more readings. During this period, the spreadsheet shows Command = 0%.
  4. Then plug the data into the spreadsheet.

You use the spreadsheet to pick 2 points during the stabilized steady rise time, and 2 points during the stabilized steady fall time. Those points are used in the calculations like an autotune, but seem to work much better than any autotune settings I have tried.

The spreadsheet includes a set of measurements from my electric smoker. I'll be doing the offset smoker in the next week or two, and will share those data as well if anyone is interested in seeing another example. Just for background, once upon a time, a long time ago, I was an electrical engineer. These days I herd cats and push on ropes. Just thought I'd apply some of that rusty math stuff to the quest for great Q and share with anyone interested.
 

Attachments

  • BBQ_PID_Tuning.zip
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Greetings all. I am new to the forum, but came across this thread while trying to set up an Inkbird PID controller for my smokers. I couldn't get it set right after much effort, so I built my own controller that I can monitor and control with a mobile device. I have had excellent results with my DIY controller. I built an excel spreadsheet that I use for measuring a pit or electric smoker. It is very simple to use, and I have zipped and attached it FYI with some data and settings.

  1. Simply start taking temp readings every minute.
  2. Hit full power (or full fan or full open damper) after a few minutes and keep measuring by the minute. Try to be accurate on time intervals. After the temperature rise rate stabilizes and is increasing the same amount each minute, take a few more minutes of readings. Spreadsheet shows Command = 100%.
  3. Then cut the power (or stop the fan or close the damper). Note the minutes when you cut power or close the damper. 4. Keep taking measurements every minute. Make sure you keep taking measurements until some time after the fall rate stabilizes and is dropping the same amount every minute. Take a few more readings. During this period, the spreadsheet shows Command = 0%.
  4. Then plug the data into the spreadsheet.

You use the spreadsheet to pick 2 points during the stabilized steady rise time, and 2 points during the stabilized steady fall time. Those points are used in the calculations like an autotune, but seem to work much better than any autotune settings I have tried.

The spreadsheet includes a set of measurements from my electric smoker. I'll be doing the offset smoker in the next week or two, and will share those data as well if anyone is interested in seeing another example. Just for background, once upon a time, a long time ago, I was an electrical engineer. These days I herd cats and push on ropes. Just thought I'd apply some of that rusty math stuff to the quest for great Q and share with anyone interested.

Woah! I just ran across this post. First, welcome to the forum (from another newbie).

Seems you know your stuff (rusty or not). Obviously you have much experience in process control or similar. Most here will not likely understand what you have presented (hence the lack of responses?) Thanks for sharing.

Question:
Your spreadsheet shows two sets of results. I'm not certain I understand what the second set represents. Could you please explain? It is, after all New Years' morning, and I'm not really awake...

I would also be interested to see more info about your controller.

I recently assembed a controller using the Mypin TA4 for an electric smoker. I have not attempted to tune it precisely yet as I've been cold smoking a lot of cheese due to the cold weather.

I look forward to performing the prescribed measurements and using your spreadsheet to calculate the results.

Thanks again for sharing, and Happy New Year to you and yours!

- John
 
Ok-
I re-read the info and I now aee that your spreadsheet provides tuning values for both PI and PID controller applications.

Your method should work well for the Mypin TA4, though the value of controller gain (Kc) must be converted to "percent proportional band" for entering the "P" term in the TA4.

Simple enough to convert:
100 ÷ Kc = proportional band (in percent).

I wish manufacturers could decide on common units to use for the P, I & D terms. This has always been a major source of confusion for anyone trying to understand PID controls.

-John
 
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