PID Controller Explained

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⌚Timestamps:
00:00 - Intro
00:49 - Examples
02:21 - PID Controller
03:28 - PLC vs. stand-alone PID controller
03:59 - PID controller parameters
05:29 - Controller tuning
06:20 - Controller tuning methods

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In this video, we’re going to talk about the PID Controller and its transformation from a single station device to what it has evolved into today. We’re going to explain why PID Controllers are used in industrial processes.

We’ll illustrate how Controller settings affect different processes under control. We’ll also provide an overview of Controller Tuning.

Let’s start with a discussion about home temperature control.
If the room temperature is below the setpoint, the furnace is turned ON. When the room temperature increases above the setpoint, the furnace turns OFF.

This type of control is referred to as ON/OFF or Bang-Bang Control. The temperature is not exactly held at the setpoint of 70°F, but cycles above and below the setpoint.

ON/OFF control may be ok for your house, but it is not ok for industrial processes or motion control. Let’s look at an example of tank level control to explain why.

The Valve fills the tank as the pump drains it. If the valve is operated with ON/OFF control, the water will fluctuate around the 50% setpoint. For our purpose, let’s say the fluctuation is ±10%. In most industrial applications, this fluctuation around the setpoint is not acceptable.

What if it’s possible to throttle the valve and place it in any position between ON and OFF?

Let’s look at how a PID Controller fits into a feedback control loop. The Controller is responsible for ensuring that the Process remains as close to the desired value as possible regardless of various disruptions.

The controller compares the Transmitter Process Variable (PV) signal, and the Setpoint.
Let’s refer to the difference between the Process Variable and the Setpoint as the Error signal.

Based on that comparison, the controller produces an output signal to operate the Final Control Element. This PID Controller output is capable of operating the Final Control Element over its entire 100% range.

The PID controller determines how much and how quickly correction is applied by using varying amounts of Proportional, Integral, and Derivative action. Each block contributes a unique signal that is added together to create the controller output signal.

- The proportional block creates an output signal proportional to the magnitude of the Error Signal.
Unfortunately, the closer you get to the setpoint, the less it pushes. Eventually, the process just runs continuously close to the setpoint, but not quite there.

- The integral block creates an output proportional to the duration and magnitude of the Error Signal. The longer the error and the greater the amount, the larger the integral output.
As long as an Error exists, Integral action will continue.

- The derivative block creates an output signal proportional to the rate of change of the error signal. The faster the error changes, the larger the derivative output.

Derivative control looks ahead to see what the error will be in the future and contributes to the controller output accordingly. That brings us to a term called Controller Tuning.

There are many different manual methods for tuning a controller that involves observing the process response after inflicting controller setpoint changes.

One method involves increasing the amount of setpoint change and repeating the procedure until the process enters a state of steady-state oscillation.

Most process controllers, PLC, and DCS loop controllers sold today have Autotuning capability.
The PID controller learns how the process responds to a change in setpoint, and suggested PID settings.

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#RealPars #PID #IndustrialAutomation

[cordaxg]

Today i continued my education to become a Enviromental Operating technician (Water & Sewage)
Today we started our course in Automation.
Im a Swede with a pretty good grasp of the english language.
I can tell you, these videos from a total beginners perspective, and not having english as a main/native language these videos were both easy to understand and grasp/follow.
Great videos !

[yungerallenelectricalcontr]

By Far the Best Explanation for PID's I have ever had the pleasure to Learn. This is a game changer for my foundation.

[johng]

Thanks in a million. Great content. Awesome. Very well explained. I couldn't find this explanation--simply put anywhere else. Great teachers are hard to find. Grade: A++💥

[nyahhbinghi]

I love it when my furnace kicks in at 65º and then heats the house to 75º, that 10º fluctuation is so glorious.

[MeltingRubberZ]

Good video. I'm an ME so I don't have to work directly on PID loops, but work in automation so I'm around them often. Back in college when we programmed them in our circuits class they had us manually use a fan to cool a resistor to a specific temperature, and then a PID loop. The precision was night and day.

[ricardogarcia]

What an educative and iteresting channel. Congrats again.

[atarperach]

Thank you very much! By far its the best explanation I have heard for PID controllers...

[tbengineering]

Thanks for the video. It really helps a lot. PID Controllers are such an important concept that can be very difficult to grasp at first. I'm going to recommend this video to some students at my alma mater. I think it will really help them understand what the Control Systems professors are talking about.

[johnatansilveira]

Thank you for your videos! I'm learning a lot from you. 🇧🇷

[arletacostagonzalez]

Very good explination. Concise and easy to understand. Thank you very much.

[eugenepohjola]

Howdy.
I like how RealPars focus on the essential in these tutorials.
Digital controllers are usually described as summing of the P, I and D blocks. As in the clip.
There are still lots of analog controllers in use. They are usually bulit using operational amplifiers. The description usually is the P, I and D in cascode or series.
The math is different for summing and cascode. However. The derivative parameter Td usually is at most 1/10 of the integral parameter Ti. Usually Td is even way smaller than 1/10 of Ti. The math for both summing and cascode will be the same closely enough.
Regards.

[WeconTechnology]

Very detailed video. Our Wecon PLC support PID tuning.

[ilhuihdez]

Great amazing content. It really facilitates understanding of the topic. Thank you thank you thank you.

[mortenlund]

Cool of you to go here. Thanks for the effort. Great video,

[eugeneleroux]

Thank you for a very informative presentation.

[fifaham]

Very good refreshing - I took 6 courses in Control Systems in the University long years ago and I loved this subject a lot, I was A student in this subject doing it with Analog circuits but today I do it with microcontollers along with Analog + DigiPots and Digital Variable Capacitor along with keyboard and switches. This is amazing.

[SEALTRONICS]

ReaLPara you are just too much, Love u guys, Keep the work

[fahimahmadosmani]

Thanks a lot. Very clear and understandable

[mahmoodahmedmughal]

very informative and conceptual video.

[ramtelange]

Thanks sir you making my day Today actually I daily face PID setting...