Fan/servo operation mode


 

Benjamin Thibault

TVWBB Member
Hi everyone. I'm super new to the Heatermeter project, but I'm loving it.

One issue I have with the operation is the way the fan and the servo interact. Currently, they either have to follow each other, or have the "on at max only/above x%" type operation. This has struck me as odd though.

I know Bryan just changed it to the "on above x%" but I was hoping a different mode could be implemented as well, as I think it's slightly more intuitive to be honest.

The way it should work, in my opinion, is the servo operate its range to open and close the damper from all the way closed to all the way open. If that's enough to control the pit awesome, if not, the fan should come in at its minimum and then work it's range through to the maximum.

So here's kind of an idea of an output I'm thinking of

http://imgur.com/YeqpWQN

Again, it's just an opinion but I think it makes more sense to have the output operate this way. Though I'm not sure if it can be implemented very easily.
 
I like this idea and I think you're right. I'd make it work like this all the time except I can see it wanted both ways, or even a third way where the servo max is after the fan min. (thinking out loud)

I think ideally you'd have a pair of sliders that represents the PID output and where the fan comes on and where the servo is full-open would be adjustable. As a contrast to the "fanActiveFloor" this would be the "servoActiveCeil". Servo on/off only would be come servoActiveCeil=1 i.e. at 1% pid output, open the servo damper all the way.

Can anyone see any disadvantages to doing it like this?
 
I like Ben's idea, it does the same thing as "on above" except the fan doesn't start blowing until the servo has fully opened (If I understand correctly?) There would need to be options to select the operation mode, like servo only (fan off), Fan+Servo (both operating simultaneously), Fan Assist (servo 0-100% followed by fan Min-Max)

What you are suggesting, Bryan, is more complicated but more flexible, which I am fully in favor of if it's not too complicated for you to implement.

Since the HM is used on so many different types of grills big and small, from low and slow to pizza oven and high heat searing, even SSR Sous Vide systems, I think it is important that flexibility remain in the configuration to control the blower and servo in at least the modes mentioned above. I think hard coding one type of behavior, such as what Ben suggested, would be a step toward simplicity but would also reduce the flexibility of the HM to adapt to some systems.

Perhaps you should consider using a standard setup such as the system suggested by Ben by default, call it "Simple Mode". Then have the option to select "Expert Mode" where the slider config Bryan suggested would be available for advanced users to fine tune their systems?
 
I'll have to think about it more but I think it would be best to add a new value which is the PID output where the servo is max open and remove the "Full open/close only" setting. I'm cool with this where I normally am not happy about adding more "knobs" because it takes one thing out to add another. If someone can come up with a good short wording for "Servo is fully open at this PID output %" for the conf page it would help!

I've thought a lot about classifying some of the configuration items as "advanced" and having a simpler config page by default. I went over it though and there's really only a couple things that wouldn't be there all the time (resist and probe offset?). I love the idea of having a preset dropdown where you can configure if it is:
Servo First, then Fan (Progressive Boost!)
Servo and Fan together (Stacked!)
Full range servo (0-100) and half range Fan (50-100)
Close at off only + Fan (Servo open/close only with normal fan)
... but I feel like these presets can be just as confusing as just entering the values where you want each to end/kick in.

I took a walk and thought about having a little graphical display that showed that servo ramp and fan ramp together so it can be visualized, but the "Startup Max" fan speed kinda kills that because now the fan needs to show 2 ramps and it becomes confusing all over again. I think for now I'll just add the servo end PID output and worry about visualizations when I redo the webui.
 
I think a good way to put it is

Classic Mode - Fan and Servo work together equally
Servo with Boost - Servo controls unless fan is needed
Servo Full or Open - Servo is fully open or closed; fan is progressive

Ben is a smart cookie and extremely capable person, I'm glad he is running one of my prototypes. Great suggestion on improvingthe heatermeter!
 
I like where this is headed. Right now (as of early tonight) my set up is on above = 99%, min = 0%, max = 10%, max on startup = 50%(?). I don't do high heat cooks per se but would probably use the other two vents to achieve and control a temp over 300 on my 18" WSM. As I said before, too much blower actually cools my fire. So if having the blower on at 10% isn't getting me up to temp, I'll just crack open the "static" vents a little. Of course still a lot to dial in since I've only had two real cooks with the HM. What I'd really like is an automatic shaker to knock the ash off late in the cook. :D.

Todd
 
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I'm glad the idea is well received, and I genuinely think it's the way it should work. Or, at least be an option. There's no sense in running the fan, if the damper is still blocking air flow in my opinion.

Thanks for the kind words Steve. This is a super awesome project, and I love the community collaboration on it.
 
Ben, you've open my eyes on my own project because I was set in the ways of running in what I'm calling Classic Mode. Granted I feel as though I have a proven concept, running the MicroDamper in what I've just called "Servo Full or Open" (which has technically been an option already) will reduce the requirement for a higher pressure fan and will reduce the cost for heatermeter owners to get in the game. It may not be a lot but a few bucks here and there can, do, and will add up.
 
How about this for the blower config:

FanMode.jpg


Fairly simple....

Always On means the fan runs from 0-100%/Min-Max, if the HM is above 0% the fan is blowing

Damper Boost means the HM will run the damper from closed to fully open then start the fan blowing from Min to Max.

OFF means Off, servo damper only.

As for the servo damper settings, that could be left as is. If you select Servo Fully open/closed, when the HM moves from 0% to anything above the servo opens fully and the fan starts blowing immediately in either "Always On" or "Damper Boost" Mode.

As for the comment about using a fan VS blower to save a buck, perhaps literally... A fan placed in a tube does not make a blower. As soon as you restrict the input or output of a typical fan the air movement is stifled by a huge factor, that's why they invented the blower style fan! The stock HM blower costs between $8-$15 depending upon where you buy it and moves plenty of air through the intake tube of a grill, while a cheap fan moves a bit of air when unrestricted but is fairly useless when forced to blow through a tube. So I don't quite understand the quest to shave $3 off the cost of the HM by changing from an effective blower to an ineffective fan... but to each his own I guess....
 
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As for the comment about using a fan VS blower to save a buck, perhaps literally... A fan placed in a tube does not make a blower. As soon as you restrict the input or output of a typical fan the air movement is stifled by a huge factor, that's why they invented the blower style fan! The stock HM blower costs between $8-$15 depending upon where you buy it and moves plenty of air through the intake tube of a grill, while a cheap fan moves a bit of air when unrestricted but is fairly useless when forced to blow through a tube. So I don't quite understand the quest to shave $3 off the cost of the HM by changing from an effective blower to an ineffective fan... but to each his own I guess....

Wow, this is a low blow. Ive tried to make all comments in my posts non specific to your design. You have a proven design, and it does work. You realize I am trying to better this project? All of my testing has shown that a fan can and does work. You are blind to the specs of fan selection, its more than just CFM output, static pressure needs to be taken into consideration. Of course a blower has higher static pressure capabilities and design shortcuts can bemade. With the small footprint of the MicroDamper as compared to the RD3 there is going to be a learning curve selecting a fan that can pull the air hard enough. The RD3 has the luxury of being oversized (though the RD3 intake is maybe 10% larger currently than the MicroDamper - I'll update the actual figure tomorrow). I've already shown it can run my akorn on the old Fan At Max Only mode so it seems to be large enough to do that. A small size difference ito my design can meet or exceed yours. I am still in prototype but will be at full design very very soon. I apologize that i have created something smaller that can be built for much less than what you continue to sell your RD3 for. I have not charged a single person more than the cost of a fan (not even including my cost of shipping), I have not charged more than what was required to ship, and i have charged nothing for my prints. I am losing money at the sake of improving this project. Your response is completely uncalled for. Has Bryan not just reduced his cost of the heatermeter kit due to demand and his abilty to reduce cost? Is that not important to you? Also, where has your expertise come from to tell me that a fan will not work? Your gut? Your engineering degree? I am the only one between us putting forth the effort to prove it can be done. Perhaps your profits have gotten in the way of improvement. Your attitude hinders progression.
 
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Wow...........I have a suggestion, if it's not broke, don't fix it! why change things and make it more complicated to run, not all of us who use the HM are using or understand ALL of the options available so far. If it becomes more complicated to use, people won't use it. That's just my 2cents, but hey what do I know. Oh, and I have been following all this since linkmeter was first started.
 
Wow...........I have a suggestion, if it's not broke, don't fix it! why change things and make it more complicated to run, not all of us who use the HM are using or understand ALL of the options available so far. If it becomes more complicated to use, people won't use it. That's just my 2cents, but hey what do I know. Oh, and I have been following all this since linkmeter was first started.

I think this potential change makes sense, and you wouldn't have to change anything with your config if you don't want to. Personally, I like the idea of having individual control of both the servo and the fan. Using only servo (damper) mode for as much of the cook as possible would allow for a more natural convection cook, while still being able to introduce forced air if wanted/needed.
 
The only setting I have ever used is fully open and close, on the servo. I guess I will stick to and build with older versions of the heatermeter software installed, if it's Removed. Unless I miss understand the what is being discussed.
 
Wow, you certainly went off like a firecracker Steve!

All I said was the stock blower doesn't cost much and works really well. The blower costs $8-15, your fan costs what, a couple dollars less? How much savings is there to be had vs sacrifice in performance here? A fans output is very limited when restricted, that's just the nature of the physical world we live in. My comment was straight forward and honest, factual from observations I have made and documented in the roto damper thread working with different blowers, fans and damper designs etc over the past two years. Anyone here who has done the same experiments will tell you the same.You yourself had commented about needing the damper wide open for the fan to be effective, because it is true... A fan makes a poor blower. This is something you will learn as you push forward with your quest to find the fan with the proper specs to push air like you want it to, in the end you will find it is called a blower! To say I have not paid attention to things like static pressure or whatever is kinda silly, particularly while touting a fan over a blower for this application.... and who told you about my engineering background anyhow? LOL

While we are stating the obvious, and I kinda have to take a deep breath before I say this, but your damper looks mighty familiar man... It's not a dead stamp for the current incarnation of the roto damper, more like the prototype I posted pics of about a year ago, I think I called it the batman damper due to the shape of the valve. Anyhow, kinda ballsie of you to take the aggressive approach with me with the data on fans vs blowers against, static pressure and all as you apparently know(?), and with your design being being as such. I don't know whether to applaud you for your keyjones or rip into you over the minutia here... LOL
 
Yah, I agree with both John B and Dave, we dont want to lose options or over complicate things.

I think the three options I suggested are pretty simple to understand.

1 Always on = Blower runs all the time
2 Damper Boost = Servo damper opens its full range then the blower runs its full range
3 OFF = Blower never runs

And the servo damper Open/Closed only option remains available so all current options are still available.

Essentially the only change from the current scheme would be instead of the blower coming on full blast at "Max Only" it would start out at Min and ramp to Max.

What do you think Dave, is that over complicated? I respect that you have been in it from the begining, but there have been lots of changes since the early linkmeter days. IMHO I think the damper opens up a whole aspect of control, but you always have the option to just use the fan like the old days and ignore the servo stuff too...
 
Wow, you certainly went off like a firecracker Steve!

All I said was the stock blower doesn't cost much and works really well. The blower costs $8-15, your fan costs what, a couple dollars less? How much savings is there to be had vs sacrifice in performance here? A fans output is very limited when restricted, that's just the nature of the physical world we live in. My comment was straight forward and honest, factual from observations I have made and documented in the roto damper thread working with different blowers, fans and damper designs etc over the past two years. Anyone here who has done the same experiments will tell you the same.You yourself had commented about needing the damper wide open for the fan to be effective, because it is true... A fan makes a poor blower. This is something you will learn as you push forward with your quest to find the fan with the proper specs to push air like you want it to, in the end you will find it is called a blower! To say I have not paid attention to things like static pressure or whatever is kinda silly, particularly while touting a fan over a blower for this application.... and who told you about my engineering background anyhow? LOL

While we are stating the obvious, and I kinda have to take a deep breath before I say this, but your damper looks mighty familiar man... It's not a dead stamp for the current incarnation of the roto damper, more like the prototype I posted pics of about a year ago, I think I called it the batman damper due to the shape of the valve. Anyhow, kinda ballsie of you to take the aggressive approach with me with the data on fans vs blowers against, static pressure and all as you apparently know(?), and with your design being being as such. I don't know whether to applaud you for your keyjones or rip into you over the minutia here... LOL

The stock blower does work for many, not everyone. I have people coming to me telling my they wasted money on a RD3 because it can't run their larger pit. My design opens up a lot more variety in fan selection. You are also mistaken when you think that the fan is the only cost of running a damper. In comparison to the RD3, the current scale of the MicroDamper would cut the cost by well over HALF for someone looking to have it printed on a 3D Hub. That alone is enough for applause - not to mention it actually works. Can you send me a link to what I'm supposedly ripping off of yours? Why couldn't you make yours work? Mine seems to be doing well. I recall seeing Bryan try out a 80mm fan but couldn't make it work. But this is no surprise since 80mm fans can't produce enough static pressure, the 40mm fans on the other hand can and do. My comment about running the MicroDamper on full open was to decrease the required static pressure. I've already found fans that work just fine as-is, but running it full open won't require a fan that can produce as much pressure thus reducing costs further. So do not call my design or the use of a fan "ineffective" because you are talking out of your *** and read what I typed incorrectly. I'm actually a super nice guy, but I don't take too kindly on backhanded comments when I am trying (and succeeding) to better this project on my own dime.
 
Wow...........I have a suggestion, if it's not broke, don't fix it! why change things and make it more complicated to run, not all of us who use the HM are using or understand ALL of the options available so far. If it becomes more complicated to use, people won't use it. That's just my 2cents, but hey what do I know. Oh, and I have been following all this since linkmeter was first started.

My intent was not to make it more complicated. On the contrary my suggestion was, in my opinion, a more intuitive way of controlling the pit. I realize that I'm new to this project, but that doesn't mean the suggestion is without merit. If you want to keep using it how it currently is, I'm sure Bryan will keep the current functionality in. But that doesn't mean that other functionality is necessarily bad. And the great thing about software is that there's room for all of the functionality you can imagine (assuming output control supports it).

I'd like to bring this thread back onto the topic of the fan/servo functionality. Maybe start another thread to discuss the pros/cons of a blower vs fan for damper controls.
 
The stock blower does work for many, not everyone. I have people coming to me telling my they wasted money on a RD3 because it can't run their larger pit.


Umm, I find that kinda hard to believe. The RD3 is not for large pits. I have made plenty of RD2 and RD3 for people and alway ask about there grill size. The older RD could accommodate blowers of upto 28cfm, plenty of CFM for the largest of home smokers. The RD3 is not made for large smokers(bigger then a 55 gallon drum). But, there is a RD25 that can handle the largest of smokers without issue, as it can accommodate blowers up to 28cfm.
 
The stock blower does work for many, not everyone. I have people coming to me telling my they wasted money on a RD3 because it can't run their larger pit. My design opens up a lot more variety in fan selection. You are also mistaken when you think that the fan is the only cost of running a damper. In comparison to the RD3, the current scale of the MicroDamper would cut the cost by well over HALF for someone looking to have it printed on a 3D Hub. That alone is enough for applause - not to mention it actually works. Can you send me a link to what I'm supposedly ripping off of yours? Why couldn't you make yours work? Mine seems to be doing well. I recall seeing Bryan try out a 80mm fan but couldn't make it work. But this is no surprise since 80mm fans can't produce enough static pressure, the 40mm fans on the other hand can and do. My comment about running the MicroDamper on full open was to decrease the required static pressure. I've already found fans that work just fine as-is, but running it full open won't require a fan that can produce as much pressure thus reducing costs further. So do not call my design or the use of a fan "ineffective" because you are talking out of your *** and read what I typed incorrectly. I'm actually a super nice guy, but I don't take too kindly on backhanded comments when I am trying (and succeeding) to better this project on my own dime.

People who have been members of this forum for more than a month or two know the damper I am referring to. Its posted in the RD thread about a year ago. I didn't pursue it because as Tom properly pointed out, the double sided valve reduces the resolution of the valve by half. In testing I found it to be a much less effective valve so I dropped it and moved on to more promising territory. Not only is the resolution cut in half, but the smallest opening it can create is two long rectangles which makes a fairly large opening to start. You get hung up on linearity but the fact is the more you close off a damper the more the rest of the grill leaks, therefore some non-linearity in the first couple % open is actually more linear in air delivery to the pit. But what do I know, right, I've only been experimenting with this stuff for over a year maybe 2 now....

On the size you are also mistaken. Do I need to take a pic of the RD3 next to a can of coors to prove its pretty damn close to the size of your damper? Not to mention you have not integrated any connectors and keep talking about needing a larger fan, by the time you have a complete design with a fan that can push air like it needs to guess what, it's gonna be about the same size damper and cost about as much to get printed anywhere.

As for running a big pit, I guess you overlooked the post made by the guy running the commercial Stumps smoker with the RD3, he gets outstanding results as do others running UDS, offset smokers, bullet smokers, kamados etc. All tested many times over, in winter and summer weather, rain and snow... Like John B and others have told you, wait for winter and report back about how well the fan holds temps in the UDS. John B, like myself, has done enough real world experiments with this stuff to have a pretty good idea what the air flow requirements are and what can deliver it. I'VE actually never got a complaint about a RD3 and if I did I would make it good one way or another. So have your people that are upset with the RD3 they got from ME contact me please. Now if they printed the parts themselves and it didn't work well I have to wash my hands of it. The stuff I print works!

As for running a variety of fans, the original RD can run a BLOWER from the stock HM blower to as large as 25CFM, while the RD3 runs the smallest blower available that has the air flow to control the majority of pits out there. Why do you think Bryan selected a blower in the first place, or the BBQ Guru, Auber, ANYONE who makes a BBQ controller? Why do they all use a blower with pretty close to the same specs? Don't you think these people all did their research with blowers and fans? If you read what I said properly I said a fan in a tube makes a poor blower. That is a comment about the physics of air movement, not a comment on "your design". If you unplug your fan and put the damper on your Akorn I think you will find the fan spins on its own without any power, you might think it was doing something.... But it's the natural convection of the Akorn drawing air through the damper making the fan spin, your damper will likely work pretty close to the same with the blower on or off.

Apparently you are a super nice guy that likes to build off other peoples work and not give them credit, and instead gives them a hard time, and thinks he deserves applause for it. I can see why you would avoid referencing my dampers, it's tough to do without giving me credit for the basis of the design, and it seems you are all about getting applause and taking credit for stuff. Giving credit where credit is due, not so much....
 
My intent was not to make it more complicated. On the contrary my suggestion was, in my opinion, a more intuitive way of controlling the pit. I realize that I'm new to this project, but that doesn't mean the suggestion is without merit. If you want to keep using it how it currently is, I'm sure Bryan will keep the current functionality in. But that doesn't mean that other functionality is necessarily bad. And the great thing about software is that there's room for all of the functionality you can imagine (assuming output control supports it).

I'd like to bring this thread back onto the topic of the fan/servo functionality. Maybe start another thread to discuss the pros/cons of a blower vs fan for damper controls.

Ben, I agree with you and like your idea. As I had stated previously, it is really not much of a departure from the functions we have already, "On at Max Only". I was fortunate enough to be part of the forum when the servo damper functions were implemented and had a hand in developing its features and functions. It was a tiny struggle to get "on at max only" implemented and accepted, and took over a year to get Bryan to move on the "On Above" function that we are experimenting with now. Your idea to have the HM open the servo damper fully and THEN start ramping the fan is a good one, hats off to you on that, I like it! That said, there are a lot of opinions here and will be plenty of disagreement and resistance to change, so expect that. It's a good thing though really, everyone weighs in, in the long run it makes for a better product.

I like the on at max only function, it's a hybrid of the old blower driven HM and the new damper controlled method, it works outstanding for low and slow cooking. However, the HM keeps marching on, most recently into Thermocouple Pit Probe territory, which leads directly into high heat cooking territory. This gives the HM more versatility and begs for new options, like the fan boost mode you are talking about. Not everyone is going to love it, then again they don't have to use it either.... As long as the legacy functions are not eliminated I think everyone should be happy.
 

 

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