How to Program a Basic PID Loop in ControlLogix
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- Опубликовано: 5 сен 2024
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In automation programming, we are often required to program a control loop for a given process to control temperature, pressure, flow rate etc. This requires a target set-point with a controlled feedback process variable.
A PID process loop controller is designed to generate an output that causes some corrective effort to be applied to a process so as to drive a measurable process variable towards the desired set-point value.
The controller uses an actuator to affect the process and a sensor to measure the results.
Often automation technicians and programmers are required to become familiar with configuring and tuning a PID loop control instruction and it can be one of most overwhelming when it comes to PLC programming topics.
In this lesson, we will discuss how a Rockwell Automation ControlLogix 5000 PLC using the Enhanced PID controller function block instruction (PIDE).
The PIDE is an Allen Bradley Logix5000 Process Automation Controller (PAC) family (ControlLogix and CompactLogix) function block that improves on the standard PID found in all their controllers.
Function block programming uses diagrams with symbols to represent function and input and output connections between functions.
While at first, this function block can be quite intimidating, it shares similarities of the standard PID instruction and you’ll only need to turn on parameters required by your control program.
In this example, we will basically get you off the ground using the PIDE instruction and the program options essential to get it working.
In case you may have forgotten what PID stands for, the P stands for Proportional gain, I for integral time and D for Derivative gain.
PID and PIDE are used for "process control" which includes the automatic control of systems such as temperature, flow rate, pressure, and speed.
The cruise control on a car is a good example of this type of control.
Basically, you tell the controller how fast you want to go, the Set-point and the controller samples the actual speed, the Process Variable, and then the controller calculates an output value, the Control Variable, and sends that signal to the gas pedal.
And just as a PID functional refresher, and using the car cruise control as an example, the “P” or proportional is described as in the farther you are from the desired speed, the more you press the gas pedal and on the other hand, the closer you are, the less you press on it.
This works well but when you get at the desired speed, based on this rule you would let off the gas completely. And the end result is your car slows down and stays a little below the desired speed. Proportional control is the main ingredient of any control but maybe a little inaccurate.
For “I “or integral, you wait for a little, and if there is no improvement you push a little more on the pedal.
If you are stuck below the desired speed for a long time without progress, you push the gas pedal a little further. If you still do not make it to the desired speed for some time, you again push the pedal a little further down.
Once you get to the desired speed you leave the pedal where it is. Integral control gives you accuracy but you have to wait.
And for “D” or derivative, you react to sudden changes. Let’s say a strong wind gust pushes your car.
Suddenly your speed surges fast upward toward the desired speed. You become startled so you release the gas pedal. As the speed surge ends and the speed stabilizes, you will then return the pedal to where it was.
Derivative control manages sudden surges and may prevent overshooting your target speed.
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#RealPars
I just finished process control last semester and i learned more in 11 minutes than i did in 2 months.
It's still a good electrical program, but you guys rock.
Amazing to hear that, Mark! Keep up the good work.
2:54 to 5:11 nice explanation of PID
This gives real insight of PID as related real world instead of dry mathematics
Great to hear that! Thanks for your support!
I was subscribed on this channel when they were starting their business! And now they one of the best popular learning platforms on the internet ! It is magnificent guys ! Keep up the good work👍🏻
Thanks a lot, Vladislav! Amazing to hear that you have been with us from the start! Happy learning :)!
as a mexican who is learning about programming, your information is incredible, thankyou soooo muchhh cause this is exactly what my teacher is asking us to learn, because this is completely necesary
Great to hear that, Roberto! We are very happy to hear that our video courses are helpful.
Just excellent.
Feeling concept clear about PID control. Please make a video on Level control with programming using PIDE block.
Really you guys doing great.
Thanks
Hi Arman!
Thanks for your comment and your suggestion. I will pass this on to our course developers!
Thanks for sharing and happy learning!
More of this please. Thanks!
Yes, I appreciate you.
Plz make a video on Ziegler niclos tuning method so i can able to understand the PID topic completely
Will request this topic from our creator team, hopefully, this will be added to our video topic list :).
ruclips.net/video/VVOi2dbtxC0/видео.html
This EEVBlog video explains the algorithm for PID tuning
Z-N tuning is not a good way to optimize controller gain. The results are awful. This hurts production. I tell anybody that wants to use Z-N tuning to go away and don’t come back until they understand pole placement or another good alternative. Anyone teaching Z-N is suspect.
@@pnachtwey depends on the process but imc tunning would usually be better with self regulating processes
@@realpars Can you also show us the modified Ziegler Nichols tuning. This is more useful
Great tutorials, thank you so much for this precious content.
I have a remarkable point : The proportional controller doesn't leave with an offset instead it finishes with oscillations. You mean maybe the PD.
Very amazing. thanks a lot. am an HVAC Tech and that really helps me to understand so many things about the temperature and air flow control in my work place.i highly need additional trainings on that please. thanks for sharing
Glad it was helpful! Thank you for the topic suggestion, I will happily pass that on to our course developers. Happy learning, Elvice!
Quite helpful. PID system and control greatly affects how a system perform and long after it has started up into operation. A not properly tuned PID System can be the bane of some operators Plant shift especially with chemical feed systems or pH control system in water system and can cause a lot of issues. A follow up video to this one properly demonstrating with animation as usual how to go about properly tuning a PID could be very helpful. It could show different examples of how you would go about tuning a loop to be Fast Reacting, Slow Reacting, Tightly Tuned, Not so Tightly Tuned etc. That can give people a proper idea how each the PID adjustments affects a tuning for various outcome in its control.
Thanks for your insightful comment, Ardent. Good suggestion about the follow up video as well. I will forward that to our creator team!
Happy learning!
Thanks,
This is one of the harder subjects to teach the young guys for sure. We use it on our furnace controls, chemical mixing, tension control, so we can't live without it.
You are welcome!
I wakeup suddenly in the accelerator sound 2.57.. from that the class starting.. very well explained.. thanks team..
Howdy. Again very nice.
Being good with Data Types are a must if one aims to be a pro with PLC:s and analog signals. Let's clear up the PLC jargon.
PLC jargon. Math jargon. Example.
Hex. Hexadecimal 7D hex = 125 dec (integer)
Integer
Decimal Integer 128 dec
Real Floating dot value 6,456 x 10 exp 4 (dot in US and comma in Europe).
Let's assume we use a 8 bit analog input. The input A/D returns a 8 bit Hex Integer value. Now we must check the manual and establish if the return is a + only monopolar value or if it is a + - bipolar value. If the return Data Type is bipolar the highest bit going ON indicates a negative integer. The monopolar span is 0 - FF hex. And the bipolar positive span is 0 - 7F, and the negative span is FF - 80 (ascending eigenvalue).
Now. The PID function block most likely will need input Data Type to be Real (floating dot). And it most likely will return in Data Type Real too. If we try to connect the analog intut return to the PID function block the programming environment will display Type Mismatch. We need to use a Data Type converting function block in between to convert Hex integer to Real. And the same at the PID return. Real must be converted to 8 bit Hex.
And observe. The programming environment does not necessarily recognize a Type Mismatch between monopolar Hex and bipolar Hex. One must be aware of the Data Type at every step of programming. If a function block recognizes a monopolar value as a bipolar value results may cathastropic when the value advances from 7F hex to 80 hex. That is a switchover from full positive to full negative.
Regards.
Thank you so much for sharing this amazing knowledge to each and everyone of us realpars, I'm an electronics engineer, and I have small knowledge in automation, with your channel I'm learning and understanding stuff deeper, I realised this is one of my favorite fields, keep up the good work guys, I'm also considering to subscribe to your classes as soon as possible. Bell activated so I would not miss any of your new videos.
Thanks a lot for your kind compliment! We are always extremely happy to hear such positive feedback! If you ever have any questions, feel free to reach out to us. Happy learning!
Thanks a lot, RealPars
You are welcome, Muhammad! Will pass your request on to our creator team.
If you know Electronics, PLL- Phase Lock Loop for an FM stereo Tuner. The PID works in the same manner.
This example is fabulous
Thank you!
Best tutorials series ever created!
Thanks great news, Vali! Thank you!
Kindly make a video for deeper explanation for PID tuning methods to know how to choose P I D factors .
Thanks for the suggestion! I will let our creator team know. Happy learning :)
great tutorial, just keep on the target i hope u make the same explanation of PID for Siemens PLCs
Thank you! Thanks for your topic suggestion, I will pass it on to our creator team and see if they can put it on the list.
12:15 Yes I will like to get additional training on this topic. Thanks RealPars.
Excellent explanations Sir.Great services. please make a video on PID tuning. Thanks
Happy to hear that, Sathish. Thanks for the topic suggestion, I will definitely go ahead and forward this to our creator team. Happy learning!
Very good demonstration and example. Plz upload some more videos and how to set up PID in Siemens S7, 200 and S7 300 PLC
Thanks for your comment and suggestion, Hammad! I will forward this to our creator team. Happy learning!
Thanks...Please can you make same video for Siemens PLC
It would be really great. In particular, I would appreciate TIA Portal enhanced PID block explanations.
Plzz upload more viedo on PID programming...👍👍
Thanks for your suggestion and feedback, Bhushan! I will surely pass this on to our course developers. Happy learning!
Thanks for the explanation. Please post a similar video but with Siemens TIA portal for S7-1500 PLC
Mohamed, this is what you can find on our course library learn.realpars.com/how-to-configure-a-pid-controller-in-tia-portal
good introduction, I am always wondering, instead of use PLC, I actually can use Raspberry Pi, relay, and python programming or node-red to implement PID control. and that is cheaper, easier, able to have more functions. If I am an investor, I really feel the risk of PCL and automation industry
You are correct, a Raspberry Pi (or Arduino) controller is much cheaper. However, for even a simple industrial application, an Raspberry Pi controller presents multiple challenges. First, Raspberry Pi analog inputs are 0-5V, whereas the industrial standard is 4-20ma at 24VDC. Analog outputs from the Raspberry Pi are typlcailly PWM, whereas in industry they are 4-20ma. Converters can be purchased or built, but this adds cost and reduces accuracy and reliability. The Raspberry Pi is s 5.1VDC device with low voltage I/O. This low level of voltage operation would be very susceptible to electrical interface in any modern plant facility. The I/O is very low power, and starting large motors or firing inductive loads would require interposing relays. Even the most I/O intensive Raspberry Pi controllers have limited I/O. A plant with 2500 I/O would require approximately 50 networked controllers. This would require an inordinate amount of overhead programming that would outstrip the capability of the Raspberry Pi controller. There are no built-in functions in the Raspberry Pi, so basic functions like PID loops have to be programmed from scratch. And I could go on. I like the Raspberry Pi controllers, and I believe they have a place in small skid-based processes or small device control, but they are not designed for large process control applications.
@@realparsWow, many thanks for your reply, appreciate you took it seriously. I like all of the technology/science parts of PLC, their proposed usages for industrial application. I got it, and I love it. I do use PLC, and I also use RPi and industrialised version of RPis. As you said, there are covert shields, 24V DC, 4-20ma are not problems, the accuracy, precision and durability can be enhanced in many ways. Programming is not a problem for the new generation, programming should be a fundamental skill. Scale problem? if 1 RPi not enough, I can use 100, even cheaper than one S7-1500. look at the container, docker tech, they are designed for scaling up. The concepts of opensource, community development are providing faster development speed, more function integration, rich options of supply. I am worried about the future of the PLC and automation industry if the current players still insist on keeping the closed, isolated approach to develop and sell (marketing) their software and hardware, and soon or later, customers would have 'opensource' options, what level of loyalty are you expecting? The ICT industry is trying to take away the cakes from traditional automation players. Just look GE, Siemens from 2014 -2019. And look Microsoft (Azure IoT), Google, AWS, where are their hands. There is a 'disruptive innovation' happening NOW. just like the time while Ford introducing T line, apple's 1st iPhone, see what Nokia, Kodak responded. You can find more case from wiki about 'disruptive innovation'...I feel it started silently for PLC, for automation, for manufacturing information systems. The war field of the commercial market is brutal, they would tell what they are going to do with you. Just check the latest interview of the founder of Raspberry Pi, read carefully about why they design RPi 4 like this. Is that for commercial use? Industrial use? Dude, I want the PLC and automation people to survive and have a happy life, they are the people far more honest and pragmatic than others, they are trying to solve the problems rather than creating problems ( abuse your data and privacy). I am not saying PLC would totally lose the market, there are many cases still need very powerful industrial control. But can they stand still in the next 5 years, 10 years? I am not sure the flags of 'Industry 4.0' and 'IoT' would help current industry players. What I see, that they are losing the business gradually. Eventually, if these big, old guys die, maybe not a bad thing; it's making new space for more creative and useful products and service. How do you think?
I enjoyed reading that reply. Especially knowing that arduinos could handle a skid application.
One other feature of a PLC are the opto coupled relays that are built in, they are more robust as they are tried and tested.
Plc manufacturers are doing fine not opensourcing their software, to do so, would put their clients and their assets at greater risk of cyberattack. Arduino and raspberry pi target to small scale/ prototyping, their business needs to be open source to catch on, where as PLC manufacturers look at what industry needs and provides it.
@@matthewmeuleman3369 thanks for your reply. Yes, PLC has done much more robust test than IoT open source device. However, we need evaluate the return of robustness, or do you want more functions maybe more useful. the question is very like when iPhone started to fight Nokia. once you connected your device to the internet, game changed lot. closed source would not be safer than open source, for example, Linux system.
Very good videos for skilled technicians
Great to hear that! Thanks for sharing!
I was waiting for this valuable topic form you. I hope it will work for me.
Great step by step explanation 👍
Thanks a lot, Mohammad!
Nice classes was learning more from realpars
Thank you!
Thank you REALPAR team.. You're making great impact !!!
Great to hear, Emmanuel! Thank you.
Awesome! Please make a video on ziegler nicolas method
Thank you, Ali! I will pass your topic request on to our creator team. Happy learning!
Thanks alot sir ....u guys are doing really fabulous work....waiting for this topic.....🙏
Please make this topic as well with an example of stand alone temperature controller.
Salam ALeykom
@@perceptronsaber4479 walaikum assalam
@@syedjawadable
do you know PLC ?
@@perceptronsaber4479 yes ..
Thanks sir you are awesome.. Please be continue on PID...
Thank you, Vikram! Happy learning!
Thanks for sharing
Our pleasure!
Real good video easy to understand.
Glad it was helpful, Christopher! Happy learning
Can you upload a PID progarm on TIA Portal? Excellent video by the way!
Thanks, Matias! I will send your topic request to our creator team.
Always great for ur videos. Expect more. Thank you
Thank you! Will do!
Kindly make a detailed vedio ho to set proportional, integral and derivative gain
Thanks for the topic suggestion, I will definitely go ahead and forward this to our creator team. Happy learning!
Would like to get more and learn more about PLC programming
Great to hear that, Kirk! In that case, you might want to have a browse through our course library learn.realpars.com/collections
Happy learning!
We need a lot of this video, I'm new in plc programme, i want to improve my skills in automation on this channel
Thanks a lot, Ramzi! Keep up the good work.
Very interesting....
Thank you!
Please make more videos on tuning and also make videos on the historian, OPC, protocols, switch configuration, GPS, many more.
Thanks for the topic suggestion, Prateek! I will pass this on to our creator team.
Siemens is definitely the best software to use in HVAC
I would like to see this lesson pertaining to the Connected Components Workbench, and an 850 controller. (If applicable) Thanks, Mike.
Thanks for your suggestion, Michael! Will definitely pass this on to our course developers.
Thanks again for sharing and happy learning!
Thanks a lot for you, Please add more information about this subject
You are very welcome, Saleh! I will pass it on to our creator team.
Thanks a lot for your help this video is very helpful and clearly explained, you are super....have a nice day
Glad it was helpful!
Excellent no words ......
Thank you so much!
Thank you very much!
Our pleasure!
more PID control content pls！！
Please explain the function block in detail because it's not understandable without explanation of the parameters and codes mentioned in the PIDE controller.
Thanks for your feedback, Rahul! Much appreciated. I will happily pass this on to our course developers.
HI, Thanks lot for this video, it is really makes more of us to share knowledge to all, "I am still interested to go Cascade PID settings and also examples for Liquid Flow rate PID.... Thnaks again.
Plz make videos for pID values choose according to the system behaviour.
Thanks for sharing your suggestion with us! I have sent this over to our course developers.
Very informative channel.. please do a video on Triconex , antisurge control,
Thanks a lot, Naag! I will send your topic request through to our creator team.
amazing explanation ! thank you 🙏
You're more than welcome!
Great video..:your channel is a perfect place for me to learn industrial stuff.
Can you make videos on topic such as DLMS/COSEM protocol for smart meters ?
sorry if this is not related. Thanks
Thanks a lot! Sure, I will pass your request on to our creator team! Happy learning.
@@realpars i will look forward to this..thanks a lot..😊😊
Very useful. Thanks....
You are very welcome!
Always love to watch your videos....
That's great to hear, Nilesh!
Better channel in youtube !
Thanks
Thank you!
Thanks for the content
Our pleasure!
Please make more videos on this topic sie
Thanks for your feedback!
Great video!!
Glad you enjoyed it, Jim!
helpful video. How can i use the autotune feature in that function block?
The autotune feature, as you can see in the video, is available on a tab in the PIDE configuration window. Autotune is a separate software product that requires a separate license. Once installed, the configuration items on the Autotune tab will be active and allow Autotune to be enabled for the loop.
@@realparsOh :( thank you very much.
do you have a lesson for control actions direct and reverse . thanks for every thing
Very good i would like to see cascade PID control if possible, the video is very informative thanks for good content
Glad to hear that! Happy learning
Does the control valves, like PCV, FCV, LCV, TCV, used in various units of petrochemical plant use PID feedback logic and PLC?
Thank you for your question. Indeed, it is possible, but it depends on the manufacturer and whether you have purchased the device with the ID feature. In the modern industrial market, many devices offer advanced features that can be obtained for an additional cost. We hope you find this information valuable in your learning experience with RealPars.
More please thanks
Thank you for such great content.
You are very welcome, John!
Thank you for the video sir , may you upload a video of PID with TIA PORTAL
You are very welcome! Happy to hear that you enjoyed it. We have a course video covering PID with Tia Portal in our Course Library bit.ly/30hOST1
Happy learning!
Thanks for real pars
You are very welcome!
Do you have video that shows differences between two "control actions"? As an example, suppose it is desired to control the temperature by reducing the input power to a heater when PV is greater than SP and increase the input power to a heater when the temperature falls below SP (i.e. take action in both cases).
RealPars has a much more detailed course on PID control available at RealPars.com. In the course, all three control modes are detailed, and the equations and actions taken by the controller are demonstrated using a TIA Portal ladder program and a Siemens S7-1516 PLC. You may want to check it out!
Thanks a lot it's really helpful !!
Great to hear that, Zineddine!
Thank you for the video.
You are very welcome!
The best channel ever, Thanks for this great informations :D
Thanks for your support, Abdeljalil!
Please make video on tia portal data logging multiple parameters ....
Thanks for the suggestion, Nilesh. I will send this request to our team.
Very knowledgeable.... 🏅 More videos. 👍
Thanks a lot, Jolaw!
How can i tune PID parameters for better accuracy
Hi Ajmer,
This is actually a vast topic and will somehow vary from one process to another.
But I promise you that we will create another video about the basics of PID tuning very soon.
Thank you
@@realpars Thanks for replying
Pl. Make a video on PIDE autotuning.
Hey Neel!
Thanks for your comment and your suggestion. I will pass this on to our course developers!
Thanks for sharing and happy learning!
THANK U SIR FOR SHARE
And in the program why did u make the proportion --> E
And Derivative --> pv ?
Nice video bro
Please make a video of the same PID programming for mitsubishi plc using Gx-works...
I will pass your topic suggestion on to our creator team! Happy learning.
@@realpars Thank you sir awaiting for the video...
Can you add how to tuning PID using ziegler nichols methode for the next conten. Thanks.
Thanks for the topic suggestion, Fahmi! I will definitely pass this on to our creator team. Happy learning!
It would be nice if you could share some freeware where we can program and test our result, some simulation platform.
Kind regards
Hi Abdul,
Thanks for your comment!
Unfortunately, we do not have any free resources to practice simulation. You are able to purchase software and hardware via our MarketPlace marketplace.realpars.com/
Hope this helps! If I can be of any further assistance, please let me know - I’m more than happy to help!
@@realpars Thanks, but as a student that would be outside my budget.
Nice video. Can you do the same for Siemens PLC?
Thanks, Andy! I will ask our creator team if they could do so. Happy learning!
Excellent content!
Thankyou, Bob!
Vielen Dank!
Bitte schön!
it is very good what you do
Great to hear that, Farouk! Thanks a lot for your support.
I would like to get a quote on training for myself and my son
Hi John,
Thanks for your comment, and great to hear that you are motivated to join with your son!
You obtain full access to our complete course library (400+ video courses) by subscribing to either our monthly package for €22.12 a month or our yearly package for €159.28
You can subscribe through the following link bit.ly/2IpeCp3
I hope this helps- please let me know if you have any other questions, and I'll do my best to assist.
Why is output signal (CVEU) connector to heater but not to control valve?
Maybe 'heater' was not the best description for the final control element in this case, but the programmer has the flexibility to tag the final control element by function or by description of the actual device. The important concept is the CVEU (control value in engineering units) is connected to the final control element to give the proper 0 - 100% output as calculated by the PID.
@@realpars thank you for the clarification. Yes, I understand the idea. I just got confused about the name of the output.
please what software are you using in your designing
Thanks for your comment!
I am actually not sure about that, as our animation is designed by our Graphic and Animation department.
Does SIEMENS have PID block as well?
Yes, the most common are CONT_C, the continuous PID control for STEP7 v 5.6 and PID_Compact for the later versions of TIA Portal. Both blocks essentially allow for the configuration of PID control, but differ in features and implementation.
Thanks alot bro.
You are very welcome.
Thanks !
What if the only language you can select is ladder diagram? How to I add function block to this list
Thank you for your inquiry. If you're using outdated PLC software lacking math capabilities or software that's over 30 years old, it might not include built-in function block features. Nowadays, most professional PLC software packages come equipped with PID function blocks. I cannot confirm if training software provides these features; you may need to upgrade to a professional version.
However, if you're proficient in mathematics and your software is up-to-date with the latest math functions, you have the option to create your own PID controller. In essence, a function block simplifies the programming process, where someone else has already designed the program structure, and you only need to input the relevant parameters. The output will then generate results for your output devices or analog and digital cards as required.
Happy learning!
Hi RealPars. Thanks for another great video! Do you have more videos on PID tuning? I really need help with that to understand it!
You are very welcome! We are working on a new video course on PID loop programming. Hopefully, that will be ready soon.
Hello! For my project, I have 1 PT and 1 FT to control a flow control valve (FCV), having setpoint of pressure = 8.5 barg and flow = 140 m3/hr. The PT is located before FCV while the FT is after FCV. When pressure reaches
What you described can be done with 2 PIDE loops setup as an override control scheme. One controller will be set up for pressure control and the other as flow control. You will then connect each output to a "low select" or "high select" block, depending on the actions of your controllers.
@@realpars Did you mean the scheme (multiloop selection) in page 6? chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/literature.rockwellautomation.com/idc/groups/literature/documents/wp/logix-wp008_-en-p.pdf
Hey
When the operators put the variables and values of parameter for the PID system respectively
They use 1- P (Gain)
2- I (Time)
3- Derivative (gain)
4- maximum o/p
5- mininum o/p
Now you have put the p 1
And I 0.5
Why ?
And why you make limit for
Pv and sp ?
Hey,
In most cases, the operators are allowed to change the Gains of "some" loops amongst all of the loops in the process. Meaning they will be given access through the monitoring system (HMI) so that they can modify these gains wherever it is necessary. The gains you see in this video are an example to start adjusting or tuning the relevant PID control loop.
If we do not make a limit for SP value then the operator may be distracted and modify the Set-point to an out of range value and blow the process up!
Thanks
@@realpars yes I get understand you well.. And maximum and minimum out put .. These are regarding limits of pv
Thank you for helping .. You're the best
I have signed with you annual on your website ... And I have getten much better with programing👍❤
Hi Ehad, sorry for the delay here. You are very welcome! Happy to hear that you are making good progress on learning PLC programming. :)
Interesting