Auber PID help

Scotte · September 28, 2006, 08:22:55 PM

Hello everyone,

I've been surfing the posts for a couple of months now and what a wealth of info. Thanks to everyone for all of the help. I've smoked shoulders and ribs and a few things in between with a great deal of success. Finally stopped smoking to post on the site. I recently mounted a PID controller from Auber in my smoker. Copied bubbas concept (Thanks alot, good work). Everything went smooth with the installation but I'm having issues with the TC and general setup. When I turned on the PID for the first time, the PV appeared to be way off. So using my maverick-73 and the cabinet temperature gauge I checked it and I'm getting a PV that is about 35 degrees off. I can't figure it out >:( The TC isn't touching anything. I set the J-type in the controller to 5 which is the setting for the J-type TC. Why am I so far off

1. When you first turn on the PID, shouldn't PV accurately give a reading of the air temperature even before you set a temp or configure it for auto tune?

2. Before I tear back into it, does it matter what wire is being used from the PID to the TC jack?

If anyone has any experience with this PID I could use the advice Thanks.

bubbagump · September 29, 2006, 03:25:04 AM

Quote from: Scotte on September 28, 2006, 08:22:55 PM
1. When you first turn on the PID, shouldn't PV accurately give a reading of the air temperature even before you set a temp or configure it for auto tune?

Yes

Quote2. Before I tear back into it, does it matter what wire is being used from the PID to the TC jack?

Yes it does matter. The wire from the PID to the thermocouple jack should be the same as the TC wire.

What TC are you using?

robs · September 29, 2006, 05:59:45 AM

If you hold the tc in your hand, does the PV go up?

Contact Suyi @ Auber. He will be happy to help you out.

Scotte · September 29, 2006, 06:51:33 AM

Thanks for the quick reply. The fact that it does make a difference what wire was being used for the connection from the PID to the TC made me investigate scientifically why this is significant. Voltage is generated due to the interaction between two different conductive metals joined together (the wires of the TC). That's how the TC works. If I used standard 18-AWG hook-up wire with the same metal between the PID and the TC, I don't believe it could accurately transmit the voltage to give a proper reading.

I'm going to fix this problem tonight and see what happens. I've got a variety of TCs here at work so I'm going to try those when I get home from work. Try to isolate the problem.

Bubba Quote:

What TC are you using? From the Allied catalog part#993-0220 J-type. The one I received is the right type, but it looks nothing like the one in the catalog. ??? No connector pin and the probe looks cheap. It cost about $17.00 with no connector pin.

Thanks bubba for the inspiration to investigate further. I'll post after this change has been made.

Thanks robs for the contact, I may need it when I get into the auto tuning feature.

robs · September 29, 2006, 08:09:16 AM

Oh yeah, if you're not using the same exact wire that the TC is made from, it's not going to work right at all. I guess I missed that.

BTW, I am very happy with the TC I bought from Auber Instruments. I did have to apply a filter (fILT) of 1 or 2 because of electrical noise, but for the price, it works fine.

Good luck.

bubbagump · September 29, 2006, 05:51:13 PM

Quote from: Scotte on September 29, 2006, 06:51:33 AM
Voltage is generated due to the interaction between two different conductive metals joined together (the wires of the TC). That's how the TC works. If I used standard 18-AWG hook-up wire with the same metal between the PID and the TC, I don't believe it could accurately transmit the voltage to give a proper reading.

Yes, Grasshopper, you are wise beyond your years. ;D ;D

Scotte · October 02, 2006, 04:57:28 AM

Problem solved ;D changed the wiring this weekend 72 degrees room temperature, perfect. Thanks again for the direction bubba and rob. I'm going to set it up tonight and put it through a trial run. This modification took a little time and money, but it will be worth it. Thank God for the Dremmel, I don't know how you can do a clean cut without it. Everything looks factory installed.

No more going to bed and waking up to find the temperature at 240 :o

I'll visit and post often. Maybe some pics of some finished product.

robs · October 02, 2006, 05:21:30 AM

Glad everything worked out. I'll be curious to know what numbers you end up with for your P, I, and D values.

Scotte · October 02, 2006, 06:01:31 AM

Rob, I think I read some where that the auto tuning feature didn't workout for you very well. Did you have to set some of the values manually to get it to reduce temp fluctuations? I think you said it was plus and minus 10 degrees, I think that is too much. Am I misinformed or did I read that? If so, what was your solution? Once I get it within two or three degrees, I'll stop tinkering.

I just read the post regarding optimal placement of the tc probe and mathematical formulas for optimizing location. I'm just going to locate the TC somewhere in the center of the cabinet without touching anything. I just don't think it needs to be that complicated. I work with math models at work all day, but at home under the influence of select adult beverages, might not be too pretty. Wow, I really see the advantage of going from the rheostat to the PID, it makes sense. I'm not sure the advantage of microing BBQ down to complex mathematical formulas. Is to simplistic to say that I added this PID so I can sleep easier :-[

bubbagump · October 02, 2006, 02:09:04 PM

Hi Scotte,

There should be no reason the auto tune feature of you Auber PID does not work. I've installed two Auber PID's in different smokers, as well as my Red Lion and have used the auto tune feature on all three with great success. If you get temp swings of 10 degrees after running auto tune some parameter is set up wrong.

The two parameters that will have the biggest affect on your PID will be your cycle time and the type of auto tune profile you select. Since your using an SSR (I assume you are) set your cycle time parameter to "0". When choosing your auto tune parameter don't choose the quickest reponse time as this will lend itself to over or undershooting your setpoint. Start with the middle one.

Also, don't start auto tune until your box temp is within about 10 degrees of your setpoint, this does make a difference. Your TC will also make a difference. It's good you are not using the Auber TC as it is very low end. Check this thread out. It explains Nodaks experience in setting up his Auber PID:

http://forum.bradleysmoker.com/index.php?topic=2829.msg25852#msg25852

Unless you have a very thorough understanding of PID control logic, I would not recommend trying to manually adjust the PID settings. Adjusting the parameter settings I noted above, my BS and the others i've done, will hold setpoint with no swing at all, except on windy days where I may see a degree of flucuation.

Good luck and have fun. :)

Bubbagump

Scotte · October 03, 2006, 06:30:42 AM

Thanks for all the info Bubba. I ran the BS through some testing last night. I would dive in and cook something, but I want to have all of the control issues worked out so I can concentrate on food preperation. I have a few comments and questions based on last nights trail and your post.

No issues with probe calibration last night. TC for the PID and the ET-73 initially were about 5 degrees off but eventually leveled out to about 1 degree. Probes are different so that is to be expected (I would assume that you would have somewhat of an insulation factor based on probe size. Over time they ended up to be about the same temperature.)

Big swings at the beginning, but adjusted the cycle time (prior to your post) from 4 to 2 and it made a big improvement.

Questions:

1. Will adjusting the cycle time on the SSR to 0 cause it to work unnecessarily hard?

2. Quote: The two parameters that will have the biggest affect on your PID will be your cycle time and the type of auto tune profile you select. "Auto tune profile", what is that? "Start with the middle one"? Is this adjustment parameter for the Auber unit? I don't see an adjustment for that specifically? Is the profile a combination of adjustments? If it is a stand alone setting, what is it's symbolic representation. (Example: Sn, Pb). If it is a combination of settings, what would be your recommendation for profile settings?

3. How long does it take to go through auto-tune? It seemed like it took about an hour and a half at 200 degress to over shoot and under shoot three times before it leveled out. Is this normal? Maybe taking your advice and waiting until the temperature is within 10 degrees will make it work more efficient.

4. Everytime you smoke do you need to run auto-tune if none of the equipment has changed. In theory, once it has a profile based on the size of your smoker, air circulation, heating element, TC, etc, and develops an algorithm based on the rate of change in temperature due to these factors, why would you need to do it everytime? Maybe weather change would be the main reason. ???

Ouote: Unless you have a very thorough understanding of PID control logic, I would not recommend trying to manually adjust the PID settings. I agree, the auto-tune feature should be more than sufficient. I put the PID in so it would be easier in the long run. If I'm playing with the settings everytime, why not just switch over to the rheostat.

robs · October 03, 2006, 06:58:48 AM

Once you tune it in, you won't have to again.

I did have to manualy jack my I value up to 2700. There's nothing wrong with tweaking the values manualy. This is why I said I was curious about your values. If auto-tune works good for you, then great. There are many variables, one being the type of TC.

I have more than one Auber PID, and they all work great. I'm sure you'll be happy.

bubbagump · October 03, 2006, 04:09:31 PM

Quote from: Scotte on October 03, 2006, 06:30:42 AM
Questions:

1. Will adjusting the cycle time on the SSR to 0 cause it to work unnecessarily hard?

2. Quote: The two parameters that will have the biggest affect on your PID will be your cycle time and the type of auto tune profile you select. "Auto tune profile", what is that? "Start with the middle one"? Is this adjustment parameter for the Auber unit? I don't see an adjustment for that specifically? Is the profile a combination of adjustments? If it is a stand alone setting, what is it's symbolic representation. (Example: Sn, Pb). If it is a combination of settings, what would be your recommendation for profile settings?

3. How long does it take to go through auto-tune? It seemed like it took about an hour and a half at 200 degress to over shoot and under shoot three times before it leveled out. Is this normal? Maybe taking your advice and waiting until the temperature is within 10 degrees will make it work more efficient.

4. Everytime you smoke do you need to run auto-tune if none of the equipment has changed. In theory, once it has a profile based on the size of your smoker, air circulation, heating element, TC, etc, and develops an algorithm based on the rate of change in temperature due to these factors, why would you need to do it everytime? Maybe weather change would be the main reason. ???

1. No setting the cycle time to "0" will not over work your SSR. They are designed to cycle frequently and the amount of cycling required to maintain setpoint in the BS is minimal compared to what they can handle. I have set all of the ones I've installed to "0" cycle time.

2. Sorry about the confusion on auto tune profiles. The Red Lion PID I have gives you the choice of three different profiles not the Auber. But, as I said, I have had no problem with the Auber auto tune feature, it works just fine.

3. Auto tune does take some time, don't be concerned. As far as waiting to starting auto tune until temp is within 10 degrees of setpoint, this is what was recommended to me by a Red Lion tech support person a long time ago. Since then I have always followed that advice with good success.

4. Auto tune is a one time thing, unless you start changing some parameters or you replace your TC. Also, adding additional heat to your BS would require retuning.

One thing about your TC, if you have to start programming in filters and offsets to compensate for errors, I would consider getting a different one. Remember, your PID is only as accurate as its input device. :)

Take care,

Bubbagump