What is a PID Controller?

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Today you will learn about PIDs. Specifically, what they are and when do we use them with automation and PLCs.

PID is an acronym that stands for Proportional, Integral, Derivative.

It can keep an automated process like temperature, pressure, or flow constant for you automatically.

PIDs use a control loop feedback or process variable to monitor where the output should be.

These usually come in the form of sensors and meters.

PIDs come in many different forms including standalone units and PLC programming.

We can use our input and output cards along with programming software to set up a PID.

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#RealPars

[electrichorror]

The absolute fundamental is: Multiply the gain, integrate the error, take the derivative of the error feed it back into the process until the desired setpoint is achived.
The values of integral, proportional and Derivative are all constants you wish to use for the error.
P(E +i( INTEGRAL) (DE) + (DE/DT)d) in the time domain, of course s domain makes it easier to solve however for most basic workings this is already provided.

[maximilianstucke]

Good info, but you sadly did not go into the details how the controller works exactly. The proportional part, integrator and derivator essentially help with uptake speed and improve smoothness and responsiveness. Imagine you set your cruise control to 150 km/h. You don't want your car to rev up and down, varying around the intended speed. The integrator helps to keep the control signal smooth. The derivator senses changes over time, hence the name, and can therefore increase the reaction speed to changes in the sensor signal. The proportional part ensures a fast uptake to the desired setting. Hence your car will accelerate quite fast until it reaches the set speed and remain there at a smooth fashion, being able to react to any changes in speed. The great thing about PIDs is, that you can set all these properties separately, having utmost control about the controller behavior.

[NomadUrpagi]

You are an exceptional channel in your quality of visual, logical and verbal presentation. Also, kudos for giving to everyone this knowledge for free. The world is ours all we have to do is grasp it.

[sultanalmahdaly]

I like how this PID is presented . It comes on very handy thank you.

[johnbarron]

This heated pipe control system is a relay controller, not PID. Relay is used when the control input is either on or off, as in a furnace for heating a house. Usually temperature control is a first-order system, with temperature being the only state, and its rate of change is proportional to a temperature differential between the heated space and the surroundings. Relay works well in this case, since the temperature of the heated space will start falling the instant the furnace is turned off, and it can be turned back on when the temperature reaches the lower setpoint. Relay controllers are the simplest kind of controller to implement; however, they are not suited to every dynamic system. Consider for example a servomotor that must swivel a robot arm from one station to another station. A relay controller would say, turn on the motor and turn it off when the arm reaches the other station. With the motor being on the whole time, the arm would acquire some angular velocity by the time it reached the other station. The task is not done though, as the arm is in motion and will overshoot the station. The motor has to reverse direction to send the arm back toward the station. This overshoot will repeat itself, leading to an unstable oscillating robot arm. This is where PD controllers come in. The P, or proportional term is the portion of the control effort due to the deviation in the actual state from the desired state. The D, or derivative term, provides damping by offsetting the control effort (servomotor applied voltage) by an amount proportional to the time rate of the state to be controlled. In the robot arm example, the initial control input from PD is relatively large due to the deviation in angular position from the desired station. As the arm picks up speed toward its destination, the proportional control term decreases due to the decreasing deviation in position, and the derivative control term, acting against the proportional term, increases. At some point before the arm reaches the destination, the derivative control term will overtake the proportional control term, at which point the motor voltage will reverse polarity, sending a slowing torque to the robot arm to slow it down to a much more manageable speed by the time it reaches the station. In this case the robot arm may overshoot the station by a little, or if the control gains are properly tuned, there will be no overshoot at all. When the desired state is a constant, PD will always send the system exactly to the desired point. However, if the desired output is a function of time, such as a ramp, or sinusoid, then there will be some steady-state lag behind the reference signal. This error can be reduced by introducing the integral, or I term to produce a full-fledged PID controller. This I term integrates the error term over time and incorporates the total error accumulation in the control input.

[DevD]

Thanks Realpars. Most awaited video. Please keep continue the PID series.

[mehmettummu]

Clearly and scientifically explanations. Thank you!

[redlamb]

Hi, my request is to.you to make more videos on This topic, your channel is very easy to understand .

[adekolasulaiman]

A big thank you to all the brain behind Realpars.

[rsasi]

Hi realpars ....thank you very much for your videos....I want to change the field ...for that everyday I am learning new things from your videos....

[sumangalauppaladinni]

I can watch thousands of videos like this. Informative and fun to watch.

[sandeep]

Very useful explaination instantly for me💓💓

[harshwardhanbhosale]

Great video, Cleared my concept related to PID.

[mitengr]

Thank you for the simple but helpful explanation.

[lct]

Hi real pars... with todays vfds that have PID control in it, would it be possible to connect the analogue output of the 1st drive to the analogue input of the second drive without using PID controllers? i would like to control the speed of the 2nd drive according to the amps of the 1st drive... the higher the amps the lower the speed and vice versa

[ndrh]

did you have any books or Docs make to understand and to learn more about PID Controller i will be thankful to you guyz !!! ...and thank you for Vds

[RakeshKumar-sxzm]

Thanks for your valuable video....
It's much useful.
I have searched on you have explained PID very well

[RamakrishnaKorukonda]

Expecting something on FeedForward control loop system

[psulife]

How to control the dc motor position control by using PID controller please upload the video releated to this

[smohammed]

During PID adjustment on PLC referring to curve of setting, proportional adjusted to get off not large unstable then value must be multiplied by 1/2 to get the actual value stable on set point. then integral (time) must be adjusted until it become constant with set point lastly will be derivative as it stand to minimise overshoot in case controller is on action such as temp, pressure or flow.