CONTROLLORE PID PDF
PID C++ implementation. GitHub Gist: instantly share code, notes, and snippets. 14, Time Position Control Motion PID Control SimulationPID Control SimulationPID Control SimulationPID Control SimulationPID Control SimulationPID Control. The pid controller is widely employed because it is very understandable and because it is quite effective. The pid then adjusts the output trying to make the input.
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NET isn’t realized as an industrial language, that is, one that can be trusted to control critical processes in near real-time performance.
This article explains the design of a PID controller in. NET that can be used to control an industrial process. There are a number of PID controller designs out there, each manufacturer taking a slightly different approach to the design. I will use the old “cruise control” example throughout controllire article to explain how this works, since a cruise control is the most observable type of PID controller out there.
The proportional term identifies what the PID controller’s reaction to the error difference between set point and output will be. Think of this as how much gas the cruise controller gives the car for some amount of error. The integral term is how the PID controller reacts to prolonged periods of error.
If we just had a P controller, the car would not accelerate going up hills or into the wind. This is an amount to add to the output per period of error.
Derivative is how much reaction the controller has versus the rate of change of the error. If we just used a PI controller, then the P term would make the speed shoot past the target, the I term would accumulate and pull it back, but it wouldn’t “anticipate” approaching the set point, and would shoot past it again.
You can find different implementations of them for particular situations, and learn about fun things like anti-windup reset.
Industrial .NET – PID Controllers
The goal of this article is to develop an easy to use PID controller. We will look at a couple different technologies implemented in this article, including delegates, threading, timing, and automation.
We will look at how to use delegates so the implementing class doesn’t need to worry about “feeding” the PID controller with data, and the PID controller can automatically update the output function.
First, let’s start off looking at the delegate setup. If you don’t know what delegates are, they are function pointers that can be passed around and stored, and you use them just like any other function. Our PID controller uses two types of delegates:. Here, we identify two delegates, or function pointers, that our application will use.
Controllore pid software example
The first one, GetDoubleis a function that takes no arguments and returns a double. The second one, SetDoubletakes a single double argument and doesn’t return anything. You can see that the implementation is rather short and sweet, but we’ll take a closer look at how the PID works It takes quite a few arguments, which I’ll explain in detail. The first argument, pGis the proportional gain, which contrlolore how ckntrollore output to apply versus the percentage error.
Industrial .NET – PID Controllers – CodeProject
The oid argument iG and the third argument dG do the same for the integral and derivative terms, respectively. The next two arguments, pMax and pMinidentify the process variable maximum and process variable minimum. This pic to say that the process variable can’t go above these values, but it will be clipped in the computation function to be within those extremes. The oMax and oMin arguments perform a similar action for the output variable. The controllofe three arguments are the delegates that tell the Cntrollore controller where it can find the data it needs to be able to process it.
I’ll skip most of the basics of the implementation, like the destructor, properties, public functions, etc. We can see that the loop is very simple; it makes a rough approximation of the amount of time that it needs to sleep this isn’t true time, because we would need to take in the amount of time it takes to run the calculation, but it’s close enough, and the Compute routine compensates by using the actual time between measurements.
All the function does is loop, sleep, and call Compute. The Compute routine is where the meat oid the algorithm lies. Basically, it starts out reading the process variable pv and set point sp. It then figures out the error percentage and starts running the PID calculation. The calculation is pretty simple; it starts out controklore the pTermwhich is the error times the gain kp. Then, inside the if statement, we do what is called anti-windup reset, where we only calculate the iTerm if the process variable isn’t pegged at or above the process variable range.
This helps to limit the output of the system, and keeps the error from blowing up when the process variable gets out of range.
It then uses the SetDouble delegate called writeOV write output variable to set the output value. And there you have it. If we have a more real-time or critical process, we can set the runThread priority to something higher, but I wouldn’t recommend going above “High” since it will cause other things to become preempted too often.
This is a very versatile class; setting the I gain term to zero will give you a PD controller, and if you wanted, you could have a strictly P controller by setting both the I and D gains to zero. There are a lot of interesting properties about PID controllers, and they can be used to perform some pretty amazing and almost intelligent control applications. This PID controller works great for implementing processes that can be modeled linear or near linear, but processes that are a lot more complicated and need a multi-parameter PID.
I’ve implemented PID controllers that use up to 18 terms, with great results, using the same simple framework. Tuning is the hard part Articles Quick Answers Messages.
Ron Beyer29 Dec Please Sign up or sign in to vote. Download source code – 6. First, a quick glossary: Proportional – the “P” element of the PID controller more on this later Integral – the “I” element of the PID controller more later Derivative – the “D” element of the PID controller more later Process Variable – the controllable variable that affects the output Set Point – Desired output value I will use the old “cruise control” example throughout the article to explain how this works, since a cruise control is the most observable type of PID controller out there.
Using the Code First, let’s start off looking at the delegate setup.
Our PID controller uses two types of delegates: Now, let’s look at the PID class: First off, the constructor: Let’s take a look at the threading loop: Points of Interest This PID controller works great for implementing processes that can be modeled linear or near linear, but processes that are a lot more complicated and need a multi-parameter PID.
I studied Software Engineering at Milwaukee School of Engineering for 2 years before switching to Management of Information Systems for a more business oriented approach.
NET, Cetc. I’ve been developing professionally since in.
Progettazione facile di controllori PID – Video – MATLAB & Simulink
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Tim Craig Dec 9: Article Alternatives Comments 29 Add your own alternative version Tagged as. NET Stats 97K views 4. If you are using in VB. SetDouble outFunc Member Dec I modified your code for my university project. I want your approval to use your code with mine.
Plus if you have any particulars that you want me to follow kindly let me know. Feel free to use this code wherever you want under whatever license you want. Thank u so much.
SSLRig is controllorf uploaded. An error is hidden in the code winnypolo Mar 1: The code should be: An error is hidden in the code JudeC Oct 0: What code do you use to calculate lastErr?
An error is hidden in the code Pera Zdera Jun 1: There is mistake in formula. An error is hidden in the code Member Jan The difference of pv and lastpv is the same as between Err and lastErr. An error is hidden in comtrollore code W G 6-Dec Though, you can assign negative kd to compensate. It is not what formula states, would confuse people not reading the code.