Temperature Swings, Minimum Feed Rate and PID Controllers - An explanation

[Threadcutter]

NERDS!!!!!!!!! I'll bet ya that a stick burner has more variance than our grills, also much less work/hassle with these grills, do whatever makes ya happy or stimulates your brain.

Prezactly

 

[Pacman]

Me ? I dont care that much. I just watch my Thermoworks “Signals” feedback and make my decisions from there.

Right there with you. I like turning out the best food possible, but I got into this whole thing to have fun and relax.

 

[Jim6820]

Right there with you. I like turning out the best food possible, but I got into this whole thing to have fun and relax.

What they said.

 

[Greg Jones]

My last post on this topic, but here is the chart from today from an American grill company with an American made (Fireboard) controller cooking ribs on my grill. If you ever think that your Chinese-made grill from a popular company here holds IT temps 3-5° from the set point, ask why an American made company shows that this is BS? These grills, regardless of where they were made, will not deviate by only 3/5°.

 

[Greg Jones]

BTW, the ribs, before wrapping, already look delicious.! Full spares, trimmed to SL cut, with the ’chef’s share’ on the grill/

 

[RHEINLEIN]

Prezactly

Agreed. We’re churning uneven sized chunks of wood and are managing to hold an even temp. I for one am glad the software “softens” the swings.
We’ll done Rec Tec and thank you.

 

[Threadcutter]

BTW, the ribs, before wrapping, already look delicious.! Full spares, trimmed to SL cut, with the ’chef’s share’ on the grill/ View attachment 19134

What time should I show up and what can I bring ?

 

[Threadcutter]

My last post on this topic, but here is the chart from today from an American grill company with an American made (Fireboard) controller cooking ribs on my grill. If you ever think that your Chinese-made grill from a popular company here holds IT temps 3-5° from the set point, ask why an American made company shows that this is BS? These grills, regardless of where they were made, will not deviate by only 3/5°. View attachment 19133

Not doubting/arguing with you in any way, but what are the details on the left/vertical/X axis ?

And, for that matter, what are the time spans on the Y axis ?

Again, not throwing stones at glass houses. I'm pretty much in agreement that most manufacturers (including Recteq) throw in software "smoothing" filters that make their long term temperature holding capabilities look much better than what they actually are.

I'd be inclined to think that the max excursions on the X/vertical axis of the graph are maybe +/- 20 degrees, maybe more (?).....

They'd probably say that "well, the "integrated/filtered temperature over time closely resembles the indicated temperature". They wouldn't necessarily be wrong, but they'd be being a bit disingenuous in doing so.

 

[Greg Jones]

Not doubting/arguing with you in any way, but what are the details on the left/vertical/X axis ?

Good point, apologies for clipping that off. The pit was set for 275°, ran between 250° and 295° for most of the cook. All the spiking activity at around 18:30 is when I wrapped them.

 

[Greg Jones]

Here’s another graph with even more data displayed. The blue line is the set point (275°), and on average for the cook, it was on the money.

 

[Threadcutter]

Good point, apologies for clipping that off. The pit was set for 275°, ran between 250° and 295° for most of the cook. All the spiking activity at around 18:30 is when I wrapped them.
View attachment 19135

Makes perfect sense, Thanks !

 

[Greg Jones]

In reflection, I realize that I wrote something earlier about BS claims that could be misunderstood that i was speaking out about something that @Ruslan124 said. That is not the case, and I’ve PM’d them to apologize and further my explanation. I believe that it is recteq that fudges these numbers through their controller algorithm, and gives their customers the expectation that the grills operate within a much closer operating range within set temps than is possible. That is the BS I was speaking of. I really do love the recteq experience, but I could use a lot less of the ‘used car salesmanship’ from the sales team.

 

[Ruslan124]

In reflection, I realize that I wrote something earlier about BS claims that could be misunderstood that i was speaking out about something that @Ruslan124 said. That is not the case, and I’ve PM’d them to apologize and further my explanation. I believe that it is recteq that fudges these numbers through their controller algorithm, and gives their customers the expectation that the grills operate within a much closer operating range within set temps than is possible. That is the BS I was speaking of. I really do love the recteq experience, but I could use a lot less of the ‘used car salesmanship’ from the sales team.

It's all good.

 

[Dr.Floyd]

I think that if the PID is too efficient the smokers would produce less smoke. Instead of using an algorithm to fudge the numbers, RecTeq should inform users that slight temperature variations are normal and promote better smoke production.

 

[RHEINLEIN]

Very much enjoying all of the explanations on how our grills work. Thanks for all of the input folks.

That said, In Jeremy Yoder's video on different brand pellets which was recently posted for us, he mentions that temperature swings produce different smoke flavors and are more complicated and preferred over an exact held temp.

This might be the bonus of having some temp swings.

Even more excited to fire up the 590 Saturday !