I'm a chemical engineering senior and I took Process Control last semester. My "Professor" read a PowerPoint in broken English and muted all chat and turned off cameras. I learned more from these 2 videos than I did that entire semester
I started tuning controllers in the late 70's vacuum tubes no less, went on as a engineering tech for KC. Did 30 years til retirement. Tuning a pid loop is more art than science. I never used derivative. derivative is like pouring molasses on the loop.
This is the best short video I've seen about PID, really like your content, understandable, interesting and straight up to the main point, this channel is awsome!! ¡Saludos desde México!
Amazing comment! Thanks a million for sharing your positive feedback with us, Daniel! If you have any questions along the way, please feel free to reach out to us at any time.
I've studied PID-controllers in university but found that my knowledge is really chaotic and unstructured. This video really helped me to structure the data. Looking forward to a new one on this topic!
One of the main problems in this field is that PID can be simplistic to get a basic understanding. But to understand control theory, you need much math and a deep understanding of things like poles and differential equations. If you took a good control course, they tend to focus on the math part, and students sometimes come out of them not grasping what they learned.
I usually set the proportional band (gain) to zero, and set the setpoint a little below what I need so when it overshoots it wont hurt anything. The temperature is going to oscillate at a specific frequency that is natural to the process. If you know that frequency (time period for 1 cycle) and the temp extremes you have everything you need to enter PI and D values. Get a stop watch, start it at the precise moment the heat turns off, on rise, just after PV passes the set point. PV will overshoot and start to cool. Note the max temperature. Its going to cool and just after crossing the set point the heat will come back on. The temperature will continue to drop, then bottom out at a certain value. Note that min temperature. The temperature will rise and just after it passes the set point the heat will turn off, stop the stopwatch at that precise moment. You now have everything you need to dial it in on the first try. Note the max and min temps (subtract the max from the min), what percentage is that value of the set point? Enter that percentage for your gain (P). The total time it took in seconds is the reset number (I or Ti). Take that Ti number and divide it by 6 and that is the Td (D) value (a good starting point for an oven). That is usually enough for everything to settle down to a nice flat line. If it is still oscillating make the proportional band larger. If it is too twitchy (reacts to quickly to changing input) or never quite recovers from an overshoot, lower the derivative. If you use this method rarely is the I off because you can very accurately measure it. Don't play with this number, especially if you got it after the system was all warmed up.
Most PI setups, fill void of missing D with feed forward, specially in motion applications. It's worth to include this parameter in next videos. Thanks guys and keep up the great work
The analogy to a person holding their hand on a valve and opening or closing it while monitoring a pressure or temperature increase/decrease is a good one. Potentially worth incorporating into future explanations. You can intuitively understand that opening a valve rapidly would result in a big change, because most people know what happens in their shower when they turn towards the hot too fast!
Currently writting a report on PID controllers as part of my control and mechatronics unit for engineering, very useful video and well explained, I liked the added information around noise in the derivitive gain, and the different layouts of a PID controller (Parallel and series ect)
🎯 Key Takeaways for quick navigation: 00:01 *A PID controller calculates P, I, and D actions based on the error, producing a Control Variable.* 01:03 *The proportional term, or P Constant, determines system responsiveness and can be referred to by various names depending on the controller type.* 01:33 *The integral term, or I Constant, removes steady-state error and can be measured in different units, affecting its adjustability.* 02:55 *Derivative constant units are typically seconds or minutes, used for predicting change in the Process Variable and creating a faster loop response.* 04:23 *Other parameters for PID controllers include algorithm types, filtering, anti-windup, and process characteristics, but are more advanced and better left for future exploration.* 05:16 *Tuning a PID loop often involves trial and error, aiming for a stable process with minimal oscillation, considering the implications of parameter adjustments on the process.* 07:38 *While PID controllers offer many parameters for adjustment, a PI controller is often sufficient for most processes, with incremental adjustments to P and I parameters for stability.* Made with HARPA AI
Most processes will benefit from adding the D coefficient. Start by slightly decreasing the Pb and setting a small D coefficient. This is especially helpful when you want to tune to be more aggressive (smaller Pb) but to minimize overshoot. Use higher D coef for systems that have higher momentum (which tend to be slow processes with undesirable overshoot).
Imagine all University lecturers were like this gentleman💓👏 , I have studied and paid my fees, but it is now that this subject is made clear with real life explanation and examples
Congratulations on a well-presented video. When our daughter was born, I decided that through playing, she would learn analysis, logic and reason, and rational thinking, rather than develop her memory to be able to recite what she read. I played with her by making her many wooden toys relevant to dynamic behavior rather than her playing with static toys. The use of mediums that do not keep their shape as, water and sand and balls and rubber bands, which could be used in both static and dynamic behavior was very helpful, in coaxing my daughter to see what matters most, but cannot be seen nor said, so easily to young children. The idea that children should be conscious of how their toys can have a Position, Velocity, Acceleration, or RATE OF CHANGES interested me, while how a child could be conscious of what needs to be "integrated" while they play, was another issue that racked my mind. * Teaching how a toy could be placed in a location is easy for any child as it is only a static situation with no rate of change. * Catching a ball in the still air, becomes more challenging. * Catching a ball while the wind is blowing at a constant rate of change or when gusting becomes an interesting mind process. * POSITIONING a toy in a particular location when the toy is suspended from a solid rod, or while the toy is suspended from an elastic rubber band, has its difficulties, and it is interesting how a child learns how to tackle the issue of positioning a toy in its place when this hangs by a non-stretchable or a stretchable string/ elastic band when there is no wind, or with constant side wind and with bursts of side wind from a fan. It is interesting to see the oscillatory motion that takes place as the child operates her hand according to the error angle when the toy reaches its final point and its inertia takes it to overshoot the target. * It is interesting how a child learns to slow down the action by introducing a slower RATE OF CHANGE by using her eyes to detect how fast the toy is approaching the target position. Through his eyes, a child detects the velocity of the toy and this is why it is imperative for children to play with dynamic toys rather than being told to just read books to study hard!! These proceedings in detecting the RATE OF CHANGE or the Derivative of position one can do by giving a moving object at least two glances where the difference of distance will give an idea of the velocity. In the industrial world, one can use a tachometer that operates on the rate of change of its coils with respect to the magnetic field but a human can do it with two consecutive glances. It is this issue of being conscious of how fast the toy is moving which would help a child slow down the final movement of approach as he comes close to the target to hit. The Derivative control signals can be learned very quickly by a child who plays with toys that have motion as bouncing balls and placing toys in their place at a fast rate. Writing the alphabet is a perfect manner to teach all the control processes that exist in an automatic control system and I do believe that people who cannot write neatly have some issues with their combination of body/mind control which is the motoring and signal processing system. * If a child is asked to place a toy that is suspended by a string on a particular location on the ground without the toy being placed on the ground, the child would do it and he would notice that the string suspending the toy is perfectly vertical with the suspension point right above the toy at the final positioning, hence no positional error exists. If the child is made to suspend the toy on its target point while a fan is placed to blow the wind horizontally, then the child at first pauses and tries without thinking too much but he would soon realize that he need to pull the hand towards the fan to ensure that the inclination of the string will pull the toy on its target while the fixed inclination on the string towards the fan will generate a force that will overcome the side drag force generated by the side wind. The child soon learns about using the first integral to get a zero error when the toy is loaded with a side wind. That is INTEGRAL CONTROL. I used to find it interesting with our daughter to set up a windy condition which is bursting effect n pulses and she used her eyes to predict what I am going to do it and she used to react beforehand, which is a prediction capacity that no industrial machine can have unless its environment is carefully monitored. When I did not permit our daughter to predict the bursts of wind then she was rather aggressive on her hand motion and I would attribute this action to a double integral action to account and react for the burst of wind faster than she would have done with a constant side wind blowing. I am fortunate to say that my daughter learned all this through playing with dynamic toys and she had no idea that she was handling PID control, but also acceleration feedback or double derivative or double integral, which could be said to be useful in controlling burst of wind.................though the use of acceleration and double integrals could be exciting due to the integrals introducing delays hence instability. Learning balancing and roller skating, ice skating, skiing on water and on snow, and balancing acts and all sport have PID control in the human having to catch or aim at a target. Unfortunately during WW2 which I remember, many young pilots died because they could not handle oblique shots at the aircraft in front of them, which not only requires a PID and detecting the rate of change at higher levels to be able to predict where the target is going to be. Getting drunk is a good way of analyzing the delay effect of applying the PID when one is sober and there one begins to understand why a drunk person oscillates to a point of instability. Well, when our daughter was of age, I took her flying and I had told her that if she wants to learn how to drive any vehicle including bicycles, motorcycles, cars, she should apply continuous movements as that would be applying a persistently exciting input which would cause the craft to undergo all movements and hence the craft would PROJECT ITS OWN CHARACTERISTIC very quickly to the operator. Well, when our daughter flew for the first time I had to take a back seat as she sat near the pilot who gave her the controls when it was safe to do so. As she took the stick in her hand, she gently applied a continuous repetitive oscillatory pitch control to which the aircraft reacted and after that, she did the same with the rolling control which she gently repeated in an oscillatory manner. Then she went for the rudder control. With her persistently excitation signals the aircraft was made to give all its secrets and information that was required about the delays in its inertia. As it was a slightly windy day, I asked her to take a route sideways to the wind and she quickly reacted to the use of the rudder to keep the aircraft straight. I had prepared the pilot as to what she was going to do and I saw him smiling, and after the flight, he said, " Does your daughter know about PID control?" to which I replied, " She does not know them by those letters or that language written or spoken symbols/words, but she knows when and how to apply them, while she plays and follows any sport and about her own stability in all circumstances of her life, even while applying lipstick and makeup which need accurate hand control. Basically, our life motion ranges from situations involving RATE OF CHANGE OF ACCELERATION, ACCELERATION,(A) VELOCITY (D), POSITION (P), FIRST INTEGRAL (I forCONSTANT WIND LOADING), AND (SECOND INTEGRAL POSSIBLY USED WITH GREAT CARE IN BURSTING WINDY CONTITON /LOADING) to replace that which cannot be predicted and could affect the motion of any entity.
Wish I had been your kid. Probably would have gone on to college and no telling where else instead of a ged. At least now I'm the uh oh go to guy where I work.
A very good demonstration, thanks for your great efforts. From Systems Engineer. I have tried auto tuning several times and it does not work. So the best tuning method what you have explained in the last section, adjust P first, then adjust T, then fine tuning.. Thanks again.
I am following this channel since Long time you Explan every Topic in a very simple Way PID is very Complicated Topic but you can Explain in a simple way so please make more videos about PID.
PLC programming software like Emerson's Proficy Machine Edition and Schneider Electric's Control Expert have PID blocks. It would be really awesome if you guys made a longer video or video series where you explore the different parameters in PLC programming PID blocks, the math behind the parameters, and then maybe tune something like a valve opening/closing. I know that's asking for a ton, just throwing stuff out there that I would personally really love to see! Thanks again for the great informative videos!
Thanks for your kind comment! We appreciate your support. Great topic suggestion as well, I will definitely go ahead and forward this to our creator team. Happy learning!
Derivative in controllers seems useful if you just average out more than one previous value, to make sense of some noise. Also it seems like an integral of the whole signal since time 0 would be useless/meaingless - wouldn't you only want recency when doing the integral? how does that work?
In reality, integral assists the proportional action by moving the PV in the same direction as proportional action. This eliminates the proportional offset. As long as an error exists, integral will adjust the output of the final control element. This is quite useful. Derivative works on the rate of change of error, and as the control actions move toward the setpoint, derivative acts to slow the tendency to overshoot the SP.
Howdy. A really good walk-through of basics. In Europe the SV - MV is usually considered positive control. That is when SV is increased it will increase the CV. I seem to reember that Omron PID units employes the negative terminology. This is that MV - SV is considered positive. If a PLC PID function block is used to control a process wich is found difficult to control fast enough still accurately a dual PID approach could help. The master PID will control the process and the slave PID will feed variable P, I and D values to the master. So. When the MV is way off the slave feeds large gain and a small I time constat to the master resulting in fast approaching. When MV is close to the SV the slave will begin feeding less gain and larger I time constants. This master - slave PID:s is actually close to the Fuzzy Logic method. In high regards.
P command is proportional to the error, I checks and makes sure error is adjusted to centre set point, D looks are the displacment speed of error from set point to minimise overshoot. Engineers correct me if i'm wrong please.
Hi Liridin! I'm sure you'll get lots of responses to your question as there are many ways to describe P, I, and D actions and responses. P is indeed proportional to the error. You might think of it as "error multiplied by some value called "Gain"". Gain is another way to express proportional response. The downside of proportional-only control is that the PV will never return to the setpoint. That's where I enters into play. Integral action will continue to make changes to the controller output until the PV does return to the setpoint. D is an interesting beast. Derivative looks at the rate of change of PV and "predicts" where it will at some future point in time, and then makes changes to the controller output accordingly. So, your comment about speed of error is correct. Derivative actions looks at the rate of change of error.
Excellent video. At 3:30 ( for derivative) what do you mean by saying, " how far in future you want to predict rate of change"? So, what is this "how far in future"? Thanks for your excellent work.
The derivative term is set to cause an output change proportional to the rate of change of the process variable. This tuning parameter is set based on where you think the process will/should go in the "future". Under normal circumstances, it takes 10-20 times the PID execution time before the full effect of an output change is fully recognized. That would normally be about 20-30 seconds for a flow or pressure loop. The higher the derivative value, the more contribution to the overall output it makes. Remember, derivative works in opposition to the integral and gain terms. With this in mind, derivative should be set to reduce the amount of overshoot that an aggressive gain and integral action produces.
Another way to consider the Derivative is as a Dampening variable. It helps to dampen sudden large changes, usually on start-up conditions or if there is a very large instant change of the process input. The damping value helps reduce the sudden effect of the "gain" ( Kp ) changing the output instantly in response to the input. It dampens the response. It can help reduce overshoot while keeping the gain high for non-instantaneous changes. It will reduce your overall dynamic response to fast inputs, but can help keep the system safer from jitter. Other ways to do this is simply to have a filter on the PV as it comes into the PI[D] controller, to help reduce instant changes from the P gains.
Gracias! At the moment we only create our video courses in English. You are always able to turn on the English subtitles as that might make it a bit easier for you. Our apologies for any inconvenience! Happy learning!
One scientific method could be using a model of the plant/system and applying classic design methods such as Frequency Analysis, Root Locus etc. I typically use Frequency Analysis. This allows the designer to evaluate the stability margins of the closed-loop controller. One of many advantages over trial and error tuning. Stability evaluation is a very important to do for professional implementations. You want to make sure that your controller performs reliably for a range of variabilities. Models can be derived analytically or by various measurements. For electro-mechanical systems, e.g. motors, I often use a simple 1. order model where I determine the mechanical time constant from measurements. I use the mechanical time constant as this is the most dominant when compared to the electrical time constant. There are benefits to using higher order models, both in performance and design features, but often 1. order models are good enough and quick to derive.
This looks like the same problem of correctly damping a harmonic oscillator. The aim is to get the damp factor to 1 to achieve critically damped state. That is the quickest way to stop the oscillation.
Thanks for clearing my doubts. I watched many video about PID many channels saying past present future. But by watching this video. I realized what is past present and future. Can u post the video about auto tuning process of PID for set value.
That depends on the application, but PID is simple, easy to apply, and available in most controllers for most process control applications. Many controllers have PID variants that are very useful: PID Gap, Error Squared, pulse width control. etc. Remember, PID is just a model alg0roithm. Technically, you could develop your own algorithm and substitute it for the PID algorithm. Of course, in that case, you would have to provide all of the internal calculations and configuration, such as anti-reset windup. In some cases, neural networks, fuzzy logic, model-based control, and other variants can be used in place of PID.
I worked as a process control engineer in the petrochemical industry for most of my career. I would say that most of the controllers at the base / regulatory layer were vanilla PI controllers. The only loops we tended to use PID were an slower responding parts of the processes. We tried error squared PI for some level applications but eventually reverted to appropriately tuned PI.
Excellent question! Integration is the mathematical operation on the error signal in a PI or PID controller due to the "I", or integral parameter. Explaining how this math function works (integral in calculus) is meaningless to most technicians. When analog controllers were the only controllers that existed (pneumatic, then single loop analog), the integral adjustment was called 'reset' because adjusting the integral action knob tended to 'reset' the process variable back towards the setpoint. So increasing the integral action helped "reset" the process variable back to the setpoint.
Hi there, Thanks for reaching out. I wish we could give you a definitive answer, but there are too many variables to consider. Thermocouples themselves are not usually intermittent. They fail open, but not very often. You may have problems with the thermocouple connections. If you suspect an issue, test the TC and associated circuitry. When you say "signal noise," do you mean you have noise in addition to the constant oscillations? Have you tried reducing the Proportional Gain?
@@realpars yes, I had noise in addition to oscillations. I went back to the basics and solved it. Set integral to 0. Set Proportional to 0.1, increase until you see oscillation, then reduce by 50%. Set integral to 0.1, increase until you see oscillation, then reduce by 50%. After 3 cycles, it stabilized. Thermocouple and furnace resistances were good, as was thermocouple position. Sometimes the basics are best I guess.
Fabulous tutorial Sir, could you explain in the function domain in the integral term how to adjust the Time value, so the integration limits? Is there a formular to calculate them, or can you adjust them as you want? Thank Youvery much
Setting the integral value can be done in several ways. At 7:00 in the video, one trial-and-error method is used, which is an accepted and common way to set the integral term. It can be more accurately calculated by using a process response curve, determining the process gain, process deadtime, and process time constant, and then applying the Ziegler-Nichols or Cohen-Coon equations for calculating the integral time. There is an excellent course at Realpars.com that explains this method in detail.
Thank you for your great videos, very intuitive and useful! A remark about Ki and Ti at 2min23 shouldn't it be expressed as Ki=Kp/Ti if we talk about cycle per minute or per second?
Ki is representative of the integral tuning parameter, which can be expressed in minutes/repeat or repeat/minute; Ki=KpTi for minutes/repeat or Ki=Kp/Ti for repeats/minute. Usually, Ti is expressed in minutes and most PLCs and DCS systems use minutes as the time base.
Hi Daniel, Thank you for your question! Yes, you are correct. The measured errors are values representing the errors. As described in the video, the INTEGRAL is the sum of these errors or values of the errors in the loop. Hope this helps, and happy learning!
Hi Abdullah. Thanks for your comment! We currently only provide our course videos in English, you are always able to turn on the English subtitles as that might make it a bit easier for you. Our apologies for any inconvenience! Happy learning!
Hi Vorapob, Thanks for your comment! I will pass this on as a topic suggestion to our course developers. This would make for a great video course. Happy learning!
In TIA portal, you can find various pid control objects under instructions --> Technology --> PID control. Information about how to use these blocks could be found in user manual or help section. Hope it gives you some insight!
Hi, I have a question, because I know how to program a PLC in ladder language, but I don't understand, in real life, how do you program a PLC with PID? Or do you need a special PLC? Really I don't understand how to apply this theory in practically way
Thanks for your question, Roberto! I will happily go ahead and pass this on to our course developers as a possible future video course. Thanks again, and happy learning!
I can’t agree with this methodology with respect to tuning a loop in a chemical process. Inducing a loop to near ringing is highly dangerous. I also never would recommend expecting the proportional parameter to ever return to set point, that’s an error the integral parameter solves over a desired time. A P only loop ever reaches set point. Process dynamics assures that. Lastly, if you don’t understand the process the loop is controlling, you’ll probably end up doing more harm than good.
Michael, thank you for your comments. The loop tuning method shown is called the Open Loop Critical Gain method, which does create a bit of oscillation, but also is an effective method of tuning. Even though it doesn't appear to follow any process dynamics., it is actually a result of the Ziegler-Nichols equation solved at a boundary. The more exact way to determine tuning parameters is to use a reaction curve to determine Kc, Tau, and Tdeadtime, and then use the Ziegler-Nichols equations to solve for Kp, Ti, and Td. This method is demonstrated in a complete multi-part course at Realpars.com using PLC logic, simulation, trending and auto-tuning.
Hi Si-Ham, Thanks for your comment! We currently only provide our course videos in English, you are always able to turn on the English subtitles as that might make it a bit easier for you. Our apologies for any inconvenience! Happy learning!
@@realpars Thank you very much for the reply, I am so grateful It is true that English is an approved and more widely used language, and I did not ask you to change the video. I just wanted it to be. I chose the language, and with your explanation, the language of the other side should be below in order to make it easier to understand, like the rest of the channels that explain pid.
Want to learn industrial automation? Go here: realpars.com
Want to train your team in industrial automation? Go here: realpars.com/business
You guys have just cut my anxiety in half... all your videos. Thank-you so much!
Amazing! We love to hear such positive feedback, many thanks!
I'm a chemical engineering senior and I took Process Control last semester. My "Professor" read a PowerPoint in broken English and muted all chat and turned off cameras. I learned more from these 2 videos than I did that entire semester
What an amazing compliment! Thanks a million for sharing that, we're happy to read such positive comments.
@@realpars simular results here except my professor is senile.
😂😂 hilarious
India has the best engineers, so far
@@Loredo_1 you have a great sense of humor
I started tuning controllers in the late 70's vacuum tubes no less, went on as a engineering tech for KC. Did 30 years til retirement. Tuning a pid loop is more art than science. I never used derivative. derivative is like pouring molasses on the loop.
Extremely helpful for precision positioning and motors
Thanks so much for this clarification!! Respect from a Bangladeshi Automation Engineer.
You're more than welcome! Happy learning
Mostafiz bhai....pid control practical konno course asse ?
This is the best short video I've seen about PID, really like your content, understandable, interesting and straight up to the main point, this channel is awsome!!
¡Saludos desde México!
Amazing comment! Thanks a million for sharing your positive feedback with us, Daniel!
If you have any questions along the way, please feel free to reach out to us at any time.
I've studied PID-controllers in university but found that my knowledge is really chaotic and unstructured. This video really helped me to structure the data. Looking forward to a new one on this topic!
That's an amazing compliment, Alexey! Many thanks for sharing that and feel free to reach out if you have any questions along the way!
Happy learning!
One of the main problems in this field is that PID can be simplistic to get a basic understanding. But to understand control theory, you need much math and a deep understanding of things like poles and differential equations. If you took a good control course, they tend to focus on the math part, and students sometimes come out of them not grasping what they learned.
I usually set the proportional band (gain) to zero, and set the setpoint a little below what I need so when it overshoots it wont hurt anything. The temperature is going to oscillate at a specific frequency that is natural to the process. If you know that frequency (time period for 1 cycle) and the temp extremes you have everything you need to enter PI and D values. Get a stop watch, start it at the precise moment the heat turns off, on rise, just after PV passes the set point. PV will overshoot and start to cool. Note the max temperature. Its going to cool and just after crossing the set point the heat will come back on. The temperature will continue to drop, then bottom out at a certain value. Note that min temperature. The temperature will rise and just after it passes the set point the heat will turn off, stop the stopwatch at that precise moment. You now have everything you need to dial it in on the first try. Note the max and min temps (subtract the max from the min), what percentage is that value of the set point? Enter that percentage for your gain (P). The total time it took in seconds is the reset number (I or Ti). Take that Ti number and divide it by 6 and that is the Td (D) value (a good starting point for an oven). That is usually enough for everything to settle down to a nice flat line. If it is still oscillating make the proportional band larger. If it is too twitchy (reacts to quickly to changing input) or never quite recovers from an overshoot, lower the derivative. If you use this method rarely is the I off because you can very accurately measure it. Don't play with this number, especially if you got it after the system was all warmed up.
Thanks for sharing that, Christopher!
Christopher, I am absolutely going to try this out. If it works, I owe you a beer.
@@randyhall4542 Well? We're waiting...
@@randyhall4542 did it work? sounds like great advice
@@HealzDog Randy's gone to heaven.... ☹.... no beer for Christopher... 😫
Most PI setups, fill void of missing D with feed forward, specially in motion applications. It's worth to include this parameter in next videos.
Thanks guys and keep up the great work
Thanks for your feedback, Farhad! Will surely pass this on to our course developers!
The analogy to a person holding their hand on a valve and opening or closing it while monitoring a pressure or temperature increase/decrease is a good one. Potentially worth incorporating into future explanations. You can intuitively understand that opening a valve rapidly would result in a big change, because most people know what happens in their shower when they turn towards the hot too fast!
😂😂 shower 🚿 good one
😂😂😂
Currently writting a report on PID controllers as part of my control and mechatronics unit for engineering, very useful video and well explained, I liked the added information around noise in the derivitive gain, and the different layouts of a PID controller (Parallel and series ect)
🎯 Key Takeaways for quick navigation:
00:01 *A PID controller calculates P, I, and D actions based on the error, producing a Control Variable.*
01:03 *The proportional term, or P Constant, determines system responsiveness and can be referred to by various names depending on the controller type.*
01:33 *The integral term, or I Constant, removes steady-state error and can be measured in different units, affecting its adjustability.*
02:55 *Derivative constant units are typically seconds or minutes, used for predicting change in the Process Variable and creating a faster loop response.*
04:23 *Other parameters for PID controllers include algorithm types, filtering, anti-windup, and process characteristics, but are more advanced and better left for future exploration.*
05:16 *Tuning a PID loop often involves trial and error, aiming for a stable process with minimal oscillation, considering the implications of parameter adjustments on the process.*
07:38 *While PID controllers offer many parameters for adjustment, a PI controller is often sufficient for most processes, with incremental adjustments to P and I parameters for stability.*
Made with HARPA AI
Most processes will benefit from adding the D coefficient. Start by slightly decreasing the Pb and setting a small D coefficient. This is especially helpful when you want to tune to be more aggressive (smaller Pb) but to minimize overshoot. Use higher D coef for systems that have higher momentum (which tend to be slow processes with undesirable overshoot).
at school the trial&error process is not explained, but the model of the controlled system is rarely know so to me this is the only option. thank you
Imagine all University lecturers were like this gentleman💓👏 , I have studied and paid my fees, but it is now that this subject is made clear with real life explanation and examples
What an amazing compliment! Many thanks for sharing, and we're very glad to hear that!
Happy learning!
Especially when you have a teacher with a language barrier.
Congratulations on a well-presented video.
When our daughter was born, I decided that through playing, she would learn analysis, logic and reason, and rational thinking, rather than develop her memory to be able to recite what she read. I played with her by making her many wooden toys relevant to dynamic behavior rather than her playing with static toys. The use of mediums that do not keep their shape as, water and sand and balls and rubber bands, which could be used in both static and dynamic behavior was very helpful, in coaxing my daughter to see what matters most, but cannot be seen nor said, so easily to young children. The idea that children should be conscious of how their toys can have a Position, Velocity, Acceleration, or RATE OF CHANGES interested me, while how a child could be conscious of what needs to be "integrated" while they play, was another issue that racked my mind.
* Teaching how a toy could be placed in a location is easy for any child as it is only a static situation with no rate of change.
* Catching a ball in the still air, becomes more challenging.
* Catching a ball while the wind is blowing at a constant rate of change or when gusting becomes an interesting mind process.
* POSITIONING a toy in a particular location when the toy is suspended from a solid rod, or while the toy is suspended from an elastic rubber band, has its difficulties, and it is interesting how a child learns how to tackle the issue of positioning a toy in its place when this hangs by a non-stretchable or a stretchable string/ elastic band when there is no wind, or with constant side wind and with bursts of side wind from a fan. It is interesting to see the oscillatory motion that takes place as the child operates her hand according to the error angle when the toy reaches its final point and its inertia takes it to overshoot the target.
* It is interesting how a child learns to slow down the action by introducing a slower RATE OF CHANGE by using her eyes to detect how fast the toy is approaching the target position. Through his eyes, a child detects the velocity of the toy and this is why it is imperative for children to play with dynamic toys rather than being told to just read books to study hard!! These proceedings in detecting the RATE OF CHANGE or the Derivative of position one can do by giving a moving object at least two glances where the difference of distance will give an idea of the velocity. In the industrial world, one can use a tachometer that operates on the rate of change of its coils with respect to the magnetic field but a human can do it with two consecutive glances. It is this issue of being conscious of how fast the toy is moving which would help a child slow down the final movement of approach as he comes close to the target to hit. The Derivative control signals can be learned very quickly by a child who plays with toys that have motion as bouncing balls and placing toys in their place at a fast rate. Writing the alphabet is a perfect manner to teach all the control processes that exist in an automatic control system and I do believe that people who cannot write neatly have some issues with their combination of body/mind control which is the motoring and signal processing system.
* If a child is asked to place a toy that is suspended by a string on a particular location on the ground without the toy being placed on the ground, the child would do it and he would notice that the string suspending the toy is perfectly vertical with the suspension point right above the toy at the final positioning, hence no positional error exists. If the child is made to suspend the toy on its target point while a fan is placed to blow the wind horizontally, then the child at first pauses and tries without thinking too much but he would soon realize that he need to pull the hand towards the fan to ensure that the inclination of the string will pull the toy on its target while the fixed inclination on the string towards the fan will generate a force that will overcome the side drag force generated by the side wind. The child soon learns about using the first integral to get a zero error when the toy is loaded with a side wind. That is INTEGRAL CONTROL.
I used to find it interesting with our daughter to set up a windy condition which is bursting effect n pulses and she used her eyes to predict what I am going to do it and she used to react beforehand, which is a prediction capacity that no industrial machine can have unless its environment is carefully monitored. When I did not permit our daughter to predict the bursts of wind then she was rather aggressive on her hand motion and I would attribute this action to a double integral action to account and react for the burst of wind faster than she would have done with a constant side wind blowing.
I am fortunate to say that my daughter learned all this through playing with dynamic toys and she had no idea that she was handling PID control, but also acceleration feedback or double derivative or double integral, which could be said to be useful in controlling burst of wind.................though the use of acceleration and double integrals could be exciting due to the integrals introducing delays hence instability.
Learning balancing and roller skating, ice skating, skiing on water and on snow, and balancing acts and all sport have PID control in the human having to catch or aim at a target. Unfortunately during WW2 which I remember, many young pilots died because they could not handle oblique shots at the aircraft in front of them, which not only requires a PID and detecting the rate of change at higher levels to be able to predict where the target is going to be. Getting drunk is a good way of analyzing the delay effect of applying the PID when one is sober and there one begins to understand why a drunk person oscillates to a point of instability.
Well, when our daughter was of age, I took her flying and I had told her that if she wants to learn how to drive any vehicle including bicycles, motorcycles, cars, she should apply continuous movements as that would be applying a persistently exciting input which would cause the craft to undergo all movements and hence the craft would PROJECT ITS OWN CHARACTERISTIC very quickly to the operator. Well, when our daughter flew for the first time I had to take a back seat as she sat near the pilot who gave her the controls when it was safe to do so. As she took the stick in her hand, she gently applied a continuous repetitive oscillatory pitch control to which the aircraft reacted and after that, she did the same with the rolling control which she gently repeated in an oscillatory manner. Then she went for the rudder control. With her persistently excitation signals the aircraft was made to give all its secrets and information that was required about the delays in its inertia. As it was a slightly windy day, I asked her to take a route sideways to the wind and she quickly reacted to the use of the rudder to keep the aircraft straight. I had prepared the pilot as to what she was going to do and I saw him smiling, and after the flight, he said, " Does your daughter know about PID control?" to which I replied, " She does not know them by those letters or that language written or spoken symbols/words, but she knows when and how to apply them, while she plays and follows any sport and about her own stability in all circumstances of her life, even while applying lipstick and makeup which need accurate hand control.
Basically, our life motion ranges from situations involving RATE OF CHANGE OF ACCELERATION, ACCELERATION,(A) VELOCITY (D), POSITION (P), FIRST INTEGRAL (I forCONSTANT WIND LOADING), AND (SECOND INTEGRAL POSSIBLY USED WITH GREAT CARE IN BURSTING WINDY CONTITON /LOADING) to replace that which cannot be predicted and could affect the motion of any entity.
Wish I had been your kid. Probably would have gone on to college and no telling where else instead of a ged.
At least now I'm the uh oh go to guy where I work.
A very good demonstration, thanks for your great efforts. From Systems Engineer. I have tried auto tuning several times and it does not work. So the best tuning method what you have explained in the last section, adjust P first, then adjust T, then fine tuning.. Thanks again.
Thanks for your support, Ahmed!
So much of respect for RealPars effort...
Thank you!
I would LOVE to see the scientific approached explained. Looking forward to that video.
Auto tune features have become my best friend 😊
For fast processes usage of D is essential. In fast electromechanics, for example. Head working in the HDD, as I know, is PD.
I cant wait for scientific approach explained. Thank you alot, that help me clearly about PID controller
Glad it was helpful!
I am following this channel since Long time you Explan every Topic in a very simple Way PID is very Complicated Topic but you can Explain in a simple way so please make more videos about PID.
Thanks a million for your kind support!
This video is fantastic! I've got to adjust the pid loop for my turbocharger controller, this really helps!
Glad you liked it!
PLC programming software like Emerson's Proficy Machine Edition and Schneider Electric's Control Expert have PID blocks. It would be really awesome if you guys made a longer video or video series where you explore the different parameters in PLC programming PID blocks, the math behind the parameters, and then maybe tune something like a valve opening/closing.
I know that's asking for a ton, just throwing stuff out there that I would personally really love to see! Thanks again for the great informative videos!
Thanks for your kind comment! We appreciate your support.
Great topic suggestion as well, I will definitely go ahead and forward this to our creator team.
Happy learning!
Thanks a loooootttt. I have cleared after years for PID controller.🙏🏻
Amazing! We're very glad to hear that, Ravi!
Nice explanation, hope that a video on adjustable parameters is coming shortly
Hi Yogesh,
Thanks for your comment and suggestion! Will happily pass this on to our course developers.
Happy learning!
This was such a great review and tutorial. Love it.
Glad you liked it!!
Nice work! Just wait for another video👍
Thanks a lot, Muhammad!
Thank you for your informative story!!!
You're more than welcome, Andry!
Thank you for the knowledge provided.
Glad it was helpful!
Derivative in controllers seems useful if you just average out more than one previous value, to make sense of some noise. Also it seems like an integral of the whole signal since time 0 would be useless/meaingless - wouldn't you only want recency when doing the integral? how does that work?
In reality, integral assists the proportional action by moving the PV in the same direction as proportional action. This eliminates the proportional offset. As long as an error exists, integral will adjust the output of the final control element. This is quite useful. Derivative works on the rate of change of error, and as the control actions move toward the setpoint, derivative acts to slow the tendency to overshoot the SP.
Howdy. A really good walk-through of basics.
In Europe the SV - MV is usually considered positive control. That is when SV is increased it will increase the CV. I seem to reember that Omron PID units employes the negative terminology. This is that MV - SV is considered positive.
If a PLC PID function block is used to control a process wich is found difficult to control fast enough still accurately a dual PID approach could help. The master PID will control the process and the slave PID will feed variable P, I and D values to the master.
So. When the MV is way off the slave feeds large gain and a small I time constat to the master resulting in fast approaching. When MV is close to the SV the slave will begin feeding less gain and larger I time constants.
This master - slave PID:s is actually close to the Fuzzy Logic method.
In high regards.
Thanks for adding that, Eugene! Much appreciated
@@realpars Yeah. Anything for a Brother or Sister in process automation.
People like you make the world a better place to live! ;)
P command is proportional to the error, I checks and makes sure error is adjusted to centre set point, D looks are the displacment speed of error from set point to minimise overshoot. Engineers correct me if i'm wrong please.
Hi Liridin! I'm sure you'll get lots of responses to your question as there are many ways to describe P, I, and D actions and responses. P is indeed proportional to the error. You might think of it as "error multiplied by some value called "Gain"". Gain is another way to express proportional response. The downside of proportional-only control is that the PV will never return to the setpoint. That's where I enters into play. Integral action will continue to make changes to the controller output until the PV does return to the setpoint. D is an interesting beast. Derivative looks at the rate of change of PV and "predicts" where it will at some future point in time, and then makes changes to the controller output accordingly. So, your comment about speed of error is correct. Derivative actions looks at the rate of change of error.
Excellent video. At 3:30 ( for derivative) what do you mean by saying, " how far in future you want to predict rate of change"? So, what is this "how far in future"?
Thanks for your excellent work.
The derivative term is set to cause an output change proportional to the rate of change of the process variable. This tuning parameter is set based on where you think the process will/should go in the "future". Under normal circumstances, it takes 10-20 times the PID execution time before the full effect of an output change is fully recognized. That would normally be about 20-30 seconds for a flow or pressure loop. The higher the derivative value, the more contribution to the overall output it makes. Remember, derivative works in opposition to the integral and gain terms. With this in mind, derivative should be set to reduce the amount of overshoot that an aggressive gain and integral action produces.
@@realpars Excellent. Thanks for your prompt reply. Keep it up...
Another way to consider the Derivative is as a Dampening variable. It helps to dampen sudden large changes, usually on start-up conditions or if there is a very large instant change of the process input. The damping value helps reduce the sudden effect of the "gain" ( Kp ) changing the output instantly in response to the input. It dampens the response. It can help reduce overshoot while keeping the gain high for non-instantaneous changes. It will reduce your overall dynamic response to fast inputs, but can help keep the system safer from jitter. Other ways to do this is simply to have a filter on the PV as it comes into the PI[D] controller, to help reduce instant changes from the P gains.
@@KyranFindlater Thanks for your excellent explanation...
Really clear explanation . Thanks!!
Glad you liked it!
great explanations… i wish i watch this sooner
Glad to hear that, Donald! Thanks for your support.
The controller knows where it is at all times. It knows this because it knows where it isn’t.
The art of tunning a PID Controller .
Very nice 👌 , thanks for taking effort for making this topic very interesting ,,, gain paramater also help in Set up PID loop in Siemens drive
Hey!
Thanks for your comment and your suggestion. I will pass this on to our course developers!
Thanks for sharing and happy learning!
Vamos muchachos ustedes pueden crear estes fantásticos videos en español! yo se que si! esperare por ellos!
Gracias! At the moment we only create our video courses in English. You are always able to turn on the English subtitles as that might make it a bit easier for you.
Our apologies for any inconvenience!
Happy learning!
@@realpars los textos deben estar en español también, quizá en un futuro puedan llegar a mas gente
Great video, good help
Thanks, @lucysmith4242! Your feedback means a lot to us! 🙌
Great explanation!
Thanks for the very informative video!
Our pleasure!
Very succinct explanation. Thanks
Great to hear that!
Great introduction to PID and Exactly the info. I need now. To the point for beginners like me. Thanks.
Glad it was helpful! Thanks for your support
really very informative 👏👌
Glad you think so!
One scientific method could be using a model of the plant/system and applying classic design methods such as Frequency Analysis, Root Locus etc.
I typically use Frequency Analysis. This allows the designer to evaluate the stability margins of the closed-loop controller. One of many advantages over trial and error tuning. Stability evaluation is a very important to do for professional implementations. You want to make sure that your controller performs reliably for a range of variabilities.
Models can be derived analytically or by various measurements. For electro-mechanical systems, e.g. motors, I often use a simple 1. order model where I determine the mechanical time constant from measurements. I use the mechanical time constant as this is the most dominant when compared to the electrical time constant. There are benefits to using higher order models, both in performance and design features, but often 1. order models are good enough and quick to derive.
Thanks for adding that!
This looks like the same problem of correctly damping a harmonic oscillator. The aim is to get the damp factor to 1 to achieve critically damped state. That is the quickest way to stop the oscillation.
Thank you! Saved me!
You're very welcome!
Well done mate keep going 👍
Thanks a lot, Maximos!
Thanks for clearing my doubts.
I watched many video about PID many channels saying past present future.
But by watching this video. I realized what is past present and future.
Can u post the video about auto tuning process of PID for set value.
Hey!
Thanks for your comment and your suggestion. I will pass this on to our course developers!
Thanks for sharing and happy learning!
Prefer to find out the open loop process and then determine closed loop tuning params to suit
Excellent Videos as always Real Pars. I have one question. Is there any other kind of controller better than PID?
That depends on the application, but PID is simple, easy to apply, and available in most controllers for most process control applications. Many controllers have PID variants that are very useful: PID Gap, Error Squared, pulse width control. etc. Remember, PID is just a model alg0roithm. Technically, you could develop your own algorithm and substitute it for the PID algorithm. Of course, in that case, you would have to provide all of the internal calculations and configuration, such as anti-reset windup. In some cases, neural networks, fuzzy logic, model-based control, and other variants can be used in place of PID.
I worked as a process control engineer in the petrochemical industry for most of my career. I would say that most of the controllers at the base / regulatory layer were vanilla PI controllers. The only loops we tended to use PID were an slower responding parts of the processes. We tried error squared PI for some level applications but eventually reverted to appropriately tuned PI.
Great presentation
Thank you, Faizal!
Perfect video. Question; why Integral mode is called Reset?
Good point...
Excellent question! Integration is the mathematical operation on the error
signal in a PI or PID controller due to the "I", or integral parameter. Explaining how this math function works (integral in calculus) is meaningless to most technicians.
When analog controllers were the only controllers that existed (pneumatic, then single loop analog), the integral adjustment was called 'reset'
because adjusting the integral action knob tended to 'reset' the process variable back towards the setpoint. So increasing the integral action helped "reset" the process variable back to the setpoint.
@@realpars Excellent work. Keep it up....
@realpsrs thank u very much for the answer!
What if I have a derivative of 0 but still have signal noise and constant oscillation. Failing thermocouple or EMI?
Hi there, Thanks for reaching out. I wish we could give you a definitive answer, but there are too many variables to consider. Thermocouples themselves are not usually intermittent. They fail open, but not very often. You may have problems with the thermocouple connections. If you suspect an issue, test the TC and associated circuitry. When you say "signal noise," do you mean you have noise in addition to the constant oscillations? Have you tried reducing the Proportional Gain?
@@realpars yes, I had noise in addition to oscillations. I went back to the basics and solved it. Set integral to 0. Set Proportional to 0.1, increase until you see oscillation, then reduce by 50%. Set integral to 0.1, increase until you see oscillation, then reduce by 50%. After 3 cycles, it stabilized. Thermocouple and furnace resistances were good, as was thermocouple position. Sometimes the basics are best I guess.
My experience with Omron controller to control water pump pressure: choose Proportional band is 100, Integral is 10,it will work ok
7:59 Please cover that in future videos. Thanks.
Thanks for your suggestion!
Is there any mobile app to find gain values by giving pv and set point
great explanations! please make video on temperature PID controllers..
Hi Akshay!
Thanks for your comment and your suggestion. I will pass this on to our course developers!
Thanks for sharing and happy learning!
Wow all this time I thought PV meant "present value". We have these PID controls at the wastewater plant i work at.
Widely used at drinking water station where I work :) (ozone dosage, lime dosage, chlorine etc.)
ruclips.net/video/zKdFlp2JTKc/видео.html
Amazing 😍
Sir..Which software are you use for this presentation?
You are better and give better.
Thank you, Mosa!
Very good job sir❤️
Thanks a lot!
Fabulous tutorial Sir, could you explain in the function domain in the integral term how to adjust the Time value, so the integration limits? Is there a formular to calculate them, or can you adjust them as you want? Thank Youvery much
Setting the integral value can be done in several ways. At 7:00 in the video, one trial-and-error method is used, which is an accepted and common way to set the integral term. It can be more accurately calculated by using a process response curve, determining the process gain, process deadtime, and process time constant, and then applying the Ziegler-Nichols or Cohen-Coon equations for calculating the integral time. There is an excellent course at Realpars.com that explains this method in detail.
Thank you for your great videos, very intuitive and useful! A remark about Ki and Ti at 2min23 shouldn't it be expressed as Ki=Kp/Ti if we talk about cycle per minute or per second?
Ki is representative of the integral tuning parameter, which can be expressed in minutes/repeat or repeat/minute; Ki=KpTi for minutes/repeat or Ki=Kp/Ti for repeats/minute. Usually, Ti is expressed in minutes and most PLCs and DCS systems use minutes as the time base.
Isn't the INTEGRAL is the sum of all measured errors instead of measured values as stated? Please help to clarify. Thanks!
Hi Daniel,
Thank you for your question!
Yes, you are correct. The measured errors are values representing the errors. As described in the video, the INTEGRAL is the sum of these errors or values of the errors in the loop.
Hope this helps, and happy learning!
Much appreciated, how to implement PID parameters to control a camera servo in C++ ? Please explain bit more.
Excellent channel, I hope translation into Arabic will be available caption.
Hi Abdullah.
Thanks for your comment! We currently only provide our course videos in English, you are always able to turn on the English subtitles as that might make it a bit easier for you.
Our apologies for any inconvenience!
Happy learning!
Many many thanks sir
Our pleasure!
How is the gas to air ratio of the boiler set? Please make a video of him.
Thanks for your suggestion, Dulal! I will make sure to pass that on to our course developers.
Thank you 👍🏻
You're very welcome!
Perfect 👏🏻
So good video
Thank you!
conceptual👍
Thank you! Happy learning
Sir, please make video for rtd lead wire compensation
Hi Patel,
Thanks for the topic suggestion, I will definitely go ahead and forward this to our creator team.
Happy learning!
Thank you.
No worries!
Cool video! Very, very weird to hear "intReg_al" from an experienced speaker though....
Thanks.
You're very welcome, Majed!
How to use PID in PLC S7-1500 ?
Hi Vorapob,
Thanks for your comment!
I will pass this on as a topic suggestion to our course developers. This would make for a great video course.
Happy learning!
In TIA portal, you can find various pid control objects under instructions --> Technology --> PID control.
Information about how to use these blocks could be found in user manual or help section.
Hope it gives you some insight!
Long life and prosperity
Hi, I have a question, because I know how to program a PLC in ladder language, but I don't understand, in real life, how do you program a PLC with PID? Or do you need a special PLC? Really I don't understand how to apply this theory in practically way
Thanks for your question, Roberto! I will happily go ahead and pass this on to our course developers as a possible future video course.
Thanks again, and happy learning!
@@realpars thanks you, I hope you will can show us how to program a PLC for a PID controller system, like a water tank, for example.
Please to be add videos for adjust parameters of PID
Thanks for your comment and topic suggestion. I will pass this on to our course developers!
Thanks for sharing and happy learning!
Love this,
Will you make a vedio on SSR(Solid State Relay)
Hey!
Thanks for your comment and your suggestion. I will pass this on to our course developers!
Thanks for sharing and happy learning!
Thank you
You're more than welcome!
An exceptionally well produced video, but the mispronunciation of “inTREgal” instead of “IInTEGral” just ignited my OCD. 🤣
Glad you enjoyed the video! 😄 We'll work on perfecting the pronunciation next time-thanks for pointing that out!
Process Variable, Set Point Variable, Control Variable??
I can’t agree with this methodology with respect to tuning a loop in a chemical process. Inducing a loop to near ringing is highly dangerous. I also never would recommend expecting the proportional parameter to ever return to set point, that’s an error the integral parameter solves over a desired time. A P only loop ever reaches set point. Process dynamics assures that. Lastly, if you don’t understand the process the loop is controlling, you’ll probably end up doing more harm than good.
Michael, thank you for your comments. The loop tuning method shown is called the Open Loop Critical Gain method, which does create a bit of oscillation, but also is an effective method of tuning. Even though it doesn't appear to follow any process dynamics., it is actually a result of the Ziegler-Nichols equation solved at a boundary. The more exact way to determine tuning parameters is to use a reaction curve to determine Kc, Tau, and Tdeadtime, and then use the Ziegler-Nichols equations to solve for Kp, Ti, and Td. This method is demonstrated in a complete multi-part course at Realpars.com using PLC logic, simulation, trending and auto-tuning.
nice
🥺😓😓Can you translate into Arabic, because this is my graduation topic, please
Hi Si-Ham,
Thanks for your comment! We currently only provide our course videos in English, you are always able to turn on the English subtitles as that might make it a bit easier for you.
Our apologies for any inconvenience!
Happy learning!
@@realpars Thank you very much for the reply, I am so grateful It is true that English is an approved and more widely used language, and I did not ask you to change the video. I just wanted it to be. I chose the language, and with your explanation, the language of the other side should be below in order to make it easier to understand, like the rest of the channels that explain pid.
👍🏻🇮🇳
🌺😘
Intregal