Need everyones help on a PID problem

[Mr Walleye]

How did the readings compare using the same TC?

Mike

[Wildcat]

I just checked an the PID was reading 197 with the MT and Maverick at 191 and 192.  Changed the PID Pb to -13.  Been having to do this all day.  Usually there is more of a difference.

[Mr Walleye]

WildCat

I must be miss reading something here...

I was under the impression you had the PID reading a given temp, then unplugged the TC off of it and plugged it (the TC from the PID) into the MTC. I was wondering if you saw any temp change between the to units, using the same TC or did I miss read your post?

Mike

[Wildcat]

Everything mentioned with the PID and MT are with the same tc.  The Maverick and MT are about 1 degree off of each other.  I started with a separate tc on the PID and MT, but one of them went bad early on.  The one that went bad was a small wired tc that is designed to wrap around something to hold it in place (disposable tc).  The one I have left is heavier gauge and has an aligator clip.

[Wildcat]

You are correct.  I am useing the same tc as described.  I can get them to read the same by adjusting the Pb, but then the fluctuations from set temp will then start.  Once I get that under control (?) then eventually the MT and PID will start reading different again.  Usually after an hour or two and by about 7 to 15 degrees.

[Mr Walleye]

I just checked an the PID was reading 197 with the MT and Maverick at 191 and 192.  Changed the PID Pb to -13.  Been having to do this all day.  Usually there is more of a difference.

Ok... still trying to get my brain around this... The PID (in this case) was reading 197 with a Pb setting of -7 (I'm guessing on the Pb setting), then you unplugged the TC off the PID and plugged it into the MTC and the MTC read 191. Next you adjusted the Pb to -13 to try and compensate for the difference.

Seem correct so far?

Mike

[Wildcat]

Yeppers.  I just checked on it and so far the PID is maintining a reading of 201 to 203 (set temp is 200).  The Maverick is reading 201.  Afraid to check the MT right now since I would have to unplug (temporarily) the tc from the PID to do so.

[Tiny Tim]

My advice now is to just let it be.  You're in the ballpark with a lot tighter tolerance than most (if not all) brand new ovens.  As long as you're paying attention to your temp, and it don't get away from the target more than 10 degrees, you're good to go.  If ya gotta set it at 220 to see 210 at the meat, so be it.

I'm sorry if that sounds harsh, but I just feel you're making it much more complicated than it has to be.

Now let's go to the bar...first round's on me.

[Mr Walleye]

You covering air fare with the first round Tiny?

:D  :D  ;D

Mike

[Wildcat]

Sorry you feel this way Tiny.  It will not stay this accurate for long.  It has fluctuated more than 10 degrees on both sides of the set temp all day.  Sometimes it stays on the mark.  Perhaps I am wrong in thinking that the PID would keep things closer to set temp than without it.

Thanks to all of you who have tried to help and I apologize for being a pain with this PID.  Perhaps it is time to do something else.

[Mr Walleye]

WildCat

WildCat

There is no question it should maintain more accurately than that, certianly there should not be that big a variation. I thought I would re-post this. It's just some thoughts on some slight temp variations on my setup and I thought it might be useful.

Mike

I find that there is a larger difference between the ET73 and the PID when I first put a load in. Then once the load starts to reach alittle higher temp the difference seems to become less. What I have done is adjust the offset once the load has been in for a few hours (3 or 4 hours with a butt). By setting it up this way I just ignore the difference and once the meat starts to get up to temp it balances out. I'll just mention though that my probes are not in the same location in the cabinet. In my situation it seems the meat effects the ET73 a little more than the PID temp probe. This makes sense because my PID TC is in the back of the cabinet and I usually clip my ET73 close to the meat to see what the meat is experiencing.

[Wildcat]

Thanks Mike.  I read that part of your post several times and it makes sense.  I am positive this is not the case at hand since all both probes are in the same location, and I am checking the PID with the MT utilizing the same tc that the PID is.  The PID is simply changing itself.

I thank you for your help my friend, but it is obvious that this post is beginning to irriate others and we should not go any further unless offline.  I will continue to try to monkey with this on my own or possibly hire someone locally, or I might just trash it.  Not worth losing friends over.  I can always look for something better than the PID, or simply just go back to useing the slider.

[Tiny Tim]

I guess I've misunderstood the whole thing so far then, and I apologize for that.  I still feel you're changing too many variables for the PID to function the way it's supposed to.

What I would do, is get the PID to be consistent before looking to match it up with readings on other devices.

There are going to be temp swings no matter what.  You have a mass that you're trying to heat up, and a heat source turning on and off to heat the air around it to heat the mass.  If you can get to a +/- 10 degree swing early in the smoke, that levels off near the end of your smoke, that's good enough.

Once you get to that ballpark, then worry about how much difference there is between the PID and your Maverick or other thermometer.  I wouldn't mess with the offset on the PID at all...just manually adjust up or down based on the Maverick reading.

As for the drink...if ya can't make it here, just tell me what you want and I'll drink it for ya too. :D

[Tiny Tim]

I just read you and Walleye's last post before mine.  I'm not irritated with the discussion...it has been informative.  I just felt that you were trying to make it way too complicated, and that's where my frustration came from.  Walleye said what pretty much what I spent the last about 15 minutes trying to say too...and I think he said it better.

[Wildcat]

Tiny, this has all taken place over a period of over 9 hours.  I have waited each time for the PID to be consistant for at least an hour or two before modifying.  But that is enough.  I have some crown and sprite in the kitchen, so if you got some - Here's to ya.