# THE TRUTH ABOUT PID CONTROLLERS

Posted by Moonshiner Chuck on

Welcome brewers, distillers, hobbyists of all types. I hope you find this as educational as it is enjoyable for me to produce. This is a discussion that will unlock the mysteries of the proportional integral derivative. I have P ID controllers they’re really old. I just wanted to do them better. I do understand the process and how a proportional integral derivative controller actually works. There are thousands of people out there that are having great results.

It's time to try to dispel some of those rumors and myths because it's real and I understand it's really easy to miss how a p ID works. All right now we do know that a p ID, we use the term p ID is real simple. It's just nothing more than a smart precise heat controller. That's really what it is, is just a smart, precise eat controller. It’s for you, without you having to do any adjustments. That's really all it is. The way it actually operates, the brain behind it is the actual p ID itself. And that's the unit that has the algorithm that compares all of the values, calculations, and behind the scenes. That's the technical aspect, what we call a solid-state relay. But that's all it does. And oh, by the way, I can prove that to you. Hook up 12 volts to it on the bottom here and the light comes on, it comes on, turns on, turns the light off turns off the same light that's here, the outline, when it flashes, it turns on turns off. So really all it's doing is turning on and turning off.

A negative, a 12 volt, and DC generator that's all I can, I can adjust the voltage and put the positive. Now when I connect, you can see the red light is on. I disconnected the red light goes out, that's that little light. And so when I reconnect it, the red light comes on just means that it's energized. What is energized? It's the optical sensor that on. So there are no physical connection contacts to burn out. That's a little bit more technical than we need to get into today. The solid state relay only turns on and off and operates. It’s is a little technical at the zero crossings of the sine wave. Therefore you don't get sparks. You understand, sometimes you'll plug in an appliance, or you unplug an appliance and you get a spark you actually based on timing, which is sheer luck, you've pulled that plug out at a point where it was not at the zero crossings of your sine wave.

Solid-state really doesn't allow to happen. It only crosses at the zero crossings, which makes it much more efficient and last a lot longer. Remember a PD controller, just in general terms, has a feedback mechanism. My thermal couple, my k type probe thermocouple. I got them with a half-inch threaded portion. I use aviation plugs on because it just makes it look neater and it works a whole lot better using the rubber bung that comes with most or you could screw them in. You could drill a hole in your column, and you could tap it and screw, you could put an adapter, or you can stick it right into the bunk. That is what I have at the top of the column.

I've got water in there and I'm using water in my test that makes it a closed-loop system. So it's constantly checking the temperature, comparing the temperature to the set value, and I have this set at 175 degrees 175 points 175 so let's bounce around 170 3.3. I can change the value, and this is the perceived value. That's what my thermal probe is sensing. It's feeling that temperature is comparing to the temperature. If you understand how a p ID works, that turning on and turning off is based on a timing function in a cycle to provide the power necessary in order to achieve a temperature without running at 100%.

I have a 3000-watt element in this mighty mini, that's a lot of overkill on 240 volts. The 100% power, a 3000-watt element withdrawal, about 13 amps. But that's a lot of energy that goes into that and that energy can actually cause a great a wide temperature spike but the pod can control to show you how it actually works. If you've run it, this 170 4.3, I still set at 175. So you can see the little red light comes on and goes off. If I push the set button it displays in, then there's a number. That's the percentage of power that it's sending to the element for the element to operate.

People get confused, but how do you know that it actually working? I've got a volt beater volt amp meter connected and you'll see right into the three amps. It's at 10% 36%. It's at eight amps. Now back down to one amp because there's only one to 2%., the VI DS sensing? What is the temperature spread between the set value and the perceived value and it's trying to provide only enough energy to maintain that set value? it works. It is almost like someone standing in front of it going up, down up. It's doing itself that's really what a p ID does. It kind of simplifies the process. They're very good for reflux stills but in a pot still, you understand it in a pot still, you'll start off at a certain temperature and you'll progressively increase the temperature in order to draw more ethanol out before you get to the tails.

That's simply because all you have to do is increase the set value on your own increments on your own timeframe. Now, let me turn that backoff. What else can this thing do? p IDs are really capable, they can do many things. If I push the button next to the set button is called the run button. At autotune, and if I push and hold that the run light comes on. Then if I push it up now I'm looking at it's at 21%. It's providing 21% power which means it's going to stay and I adjust it so now I can use it. My temperature starting to really climb because I'm providing 28% power to the element.

The element is now on constant and lets me turn it down. If I turn the element down to 2% you should see the temperature starts to drop a little bit because that element is just barely on. When the amperage and the voltage drop in a rated we use a 240-volt element, and we only provide 120 volts to it. The element only operates at 25%. So that means it’s a 3000-watt element, if you run that on 120 volts 25% of that 3000 watts is only 750 watts. So that means it wouldn't be operating as a 750-watt element, not as energetic. Not as energetic as it could be? Unless you run it at 100%, which would be 3000 watts.

You can see that your P ID does that all the time. It's constantly doing that. Let me turn to the automatic manual that runs off all you do is push the set, the button is at the run button, and turn it off. My set temperature is at zero. That's the Output percentage of the P ID to the element, that element is totally off. Now when that temperature drops down below, it starts getting closer to 175. My p ID is going to take the test, what I love about them is it starts to spread and the spread starts to close up. It makes a calculation it says at the rate that moving in a couple of extra seconds, it's going to drop below. It'll throw in a three or 489 percent for just a couple of seconds to try to arrest the drop so it doesn't drop below and then it does the same thing it shuts off before it gets to the temperature so it doesn't go above and that's where you get the precise control.

It's 4% because it 170 6.3. So what it's trying to do is try to arrest the drop and what it'll do is it'll balance itself back out at 175 degrees. We're going to do another one on and I also produce pulse-width modulators PW M's. The only difference is a pulse width modulator doesn't have a feedback mechanism. So it makes all the onus on the individual to operate. As opposed to a feedback mechanism. It operates on its own you're going to provide your own thermometer if you're using a pulse width modulator. I'm working on a chemical development to test to try to put to dispel all the rumors and myths about methanol. I'm going to try to develop a home test that you can use a couple of drops, they call that a region a couple of drops and get a reaction to tell whether you have methanol or not.

Remember, I've always said you're not going to produce enough methanol is still to hurt anybody unless you pull it out pure and consume it, which I wouldn't recommend you do. I mean the bottom line is we don't separate methanol from beer. We don't separate it from wine. But for some reason when it comes to spirits, we get all wrapped around the axle about it. I do understand but just understand that there is a fear out there. There are an absolute myth and fear that that still is going to make you go blind. It's going to kill you. Methanol comes off first, doesn't smear through the whole run. I'll get to chemically.

It molecularity proves that to you, too. They'll always be someone out there who just doesn't agree and I'm okay with that.

Happy Distilling!