Need everyones help on a PID problem

[Wildcat]

Forgot to mention, the cycle time is back at its original setting.  When I had changed it to 0 everything went crazy.  That is why I changed it back and did the auto tune again.

[Mr Walleye]

That seems odd WildCat, The cycle time should increase the accuracy if anything. Once you get things levelled out temp wise you should try setting it to 0 again and let it run for a bit to test it. If it doesn't work you can always set it back. As long as you keep the same P, I & D numbers you shouldn't affect it.

Mike

[Wildcat]

Will do.  I also forgot to mention that when I adjusted the PID to match the ET-73 I also adjusted the set temp on the PID to 205.  Both PID and ET-73 are still in sinc, although the ET-73 climbs and falls at a slower rate.  Still running +/- 1 degree from the 205 set.

I did test the ET-73 with boiling water.  Am I correct that water boils at about 212 degrees F?  The ET-73 smoker probed tested at 210 and the meat probe at 211.

[Mr Walleye]

212 is more or less correct. You can adjust for altitude. I have seen a web site that had a little program that would calculate it for you but I can't remember where it was.

Sounds like your starting to get it dialed in though!  ;)

Mike

[Wildcat]

I think I am getting there.  After adjusting the temp back to 0, it stays on my 205 setting longer.  It still touches on 206 and 204, but just briefly.  The ET-73 went up to 206 then to 207 then to 206.  I may have to adjust the Pb another notch, but I think I am zeroing in.

[Mr Walleye]

A little fine tuning and you'll have it nailed!  8)

Mike

[Arcs_n_Sparks]

A little fine tuning and you'll have it nailed!  8)

Fine tuning is making me thirsty.   :D :D :D

Underscores that this is about the Porter Indicating Device.

[Wildcat]

Oops.  Spoke too soon.  Went back to look after typing the above and the PID was showing 203 and the ET-73 showing 201.  PID climbed back to 205 while I was watching.  May have to do another auto tune with these new settings.  If that does not do it, my guess is that it is the PID probe that is causing the difficulity.  Not enough swing to really worry about, just trying to get it the best I can.

[Arcs_n_Sparks]

Plus or minus a few degrees is pretty good in my line of work. I suggest you declare success and enjoy.....

Arcs_n_Sparks

[Mr Walleye]

I would run it for a while and see how it works.

If you do run another autotune you may want to check all your settings again. I'm not sure if the autotune has any effect on them or not.

Mike

[Wildcat]

Declared.  Going for another thirst quincher.  I will still try to fine tune a little bit, but not overly concerned.  It is working much better at keeping the temperature constant than when I was just using the slider.  ;)

[Wildcat]

Thanks Mike.  I will do just that.

[Mr Walleye]

WildCat

How did your butt turn out? Did you temps continue to hold?

Mike

[MRH]

So the  thermocouple probe it shouldn't be touching any metal?  I have always just hung mine with a piece of wire under the first or second rack down from the top and it always seemed fine.

Mark

[pensrock]

MRH,
I think it depends on the controller, type of probe and how well the whole unit is grounded. I have seen computer controller furnaces go nuts if the probe touched a grounded piece of metal. Other controllers it does not effect. I know some probes are grounded at the tip and others are not, some need resistors across the probe wires at the controller. Which you need to use? I do not know? Maybe Arcs has some input on this, he is real knowledgeable with electronics. The other thing you could do is to contact the controller manufacture and explain what you are using the controller for and let them suggest what type of probe would work best for that application.
pensrock