RIMS the concept?

[thekraken]

All said-and-done and regardless: No one can debate that the classic black square face with shinny red numerals, compact-sized PID controller mounted in a panel looks more impressive than a Johnson controller on-a-rope.

Hmm, that depends entirely on the rope.

 

[PlexVector]

Hmm, that depends entirely on the rope.

Can't argue with that...

 

[alphaomega]

I guess I like a good, healthy debate. But you won't see me flip-flop like you have done.

How about this: Post a solution that someone can actually use instead of rhetoric. To the person reading this wanting to know how to implement a solution, how would they use fuzzy logic? You have an off-the-shelf FL controller to recommend? Or maybe you are proposing a DIY, using for example, an Arduino and its code? If so, post up. With costs, parts list, build instructions, etc. That would be helpful and appreciated by the community, I am certain.

Seriously, I am not trying to be a dick though I will understand that you feel otherwise. I am trying to help people here, and I don't personally feel think that academic concepts without practical implementations do that.

When have I flip-flopped? I've said all along that PID controllers are cheap and accessible and that they DO work. But that you don't *have* to use PID, especially if rolling your own controller.
Am I really required to post a completed controller to make that claim? Ain't part of DIY'ing doing it *yourself*? I am sure there are fuzzy logic controllers out there, but you'd be missing a key thing. When you write your own controller, you can make it solve *your* problem. Not a generic problem, as the available controllers do.
And I've already posted pseudo code for how the controller logic might work. But, that is just as an example. To control *your* system, you should implement it in *your* way. Set your constraints. This is easier to do that solve a generic problem.
For example, say you don't want it going above X watts when maintaining temperature. Then do that. You want it to automatically do steps. Then do that.
Arduino is an easy platform, even for beginners, and they also are accessible and cheap. All you really need is an Arduino, a tempprobe or two, a solid state relay and willingness to have some fun

But no, I can't give you an out of the box plug and play solution (not that PID controllers are really that either, but yes, *you* will need to do more 'work' going the Arduino route).
Now, there are serveral arduino projects for controlling mashing. But I really think *you* should explore this yourself. Does any of them solve *your* problem, any that you could 'steal' from or just learn from?

I don't think this is academic. The Arduino is a very real product. And it is cheaper and helluva more versatile than a PID controller.

I already said this is not for everyone. Not that I don't think everyone *could* if they wanted to, some people rather just spend their time brewing instead. But, there are a lot of people who just don't realize how easy getting started with Arduino is. And I don't think it would take you long to build a better controller (for your system) than anything store bought.

 

[thekraken]

Or maybe you are proposing a DIY, using for example, an Arduino and its code? If so, post up. With costs, parts list, build instructions, etc. That would be helpful and appreciated by the community, I am certain.

Here ya go: https://www.homebrewtalk.com/showthread.php?t=540002

It uses PID or PWM. I took a quick look at the code and modifying it to use a custom temperature control algorithm would be *super* easy. It uses the standard arduino PID library, all one would have to do is rig up a drop in replacement for the pid library. (The word 'library' makes it sound like it would might be complicated, but having played with it a lot myself I can tell you this is a simple one)

 

[PlexVector]

I've been brewing for some time and I'm about to ask some thing real dumb

As a background, Ive built and used a number of electric systems, my temperature probe has either been mounted in the bottom of the urn/kettle or in the wort return line of a recirculating BIAB.

In both these configurations the PID setup (auto tune) is dependent on the volume of wort and in the case of the recirculating BIAB the flow rate as well as the volume.

In the case with a RIMS were the temp probe is on the outlet of the heater assembly.

Its obvious that the PID setup is dependent on flow rate through the heater assembly but is it also dependent on the volume of wort and the effects of grain additions?

Or to put it another way, if I had a RIMS setup on the side of my BIAB would it matter how much wort I had in the URN.?

I take it I'd need a powerful ULD heating element to make this work?

Atb. Aamcle.

REBOOT!

Hey, great questions.

1. Its obvious that the PID setup is dependent on flow rate through the heater assembly but is it also dependent on the volume of wort and the effects of grain additions?

Only the volume through the RIMs tube. The RIMs has no concept of what's outside itself.

2. I take it I'd need a powerful ULD heating element to make this work?

Not really. The heating element wattage will control how long it takes to heat up the mass in the mash tun. For a fixed wattage it will take longer to heat up a larger mass than a smaller one, where mass is equal to the mass of the liquor plus the mass of the grain assuming no heat loss of the system, and initial starting temp and end temperature (setpoint)



EDIT: There is an optimum flow rate that enters into the equation for how long it will take to heat up the mass tun.

 

[dyqik]

A proportional only control (tuning kI and kD to zero) would essentially get you a fuzzy logic controller right?

Which is pretty much what autotuning set the parameters to on my MyPin RIMS controller...