PID control

[saed]

I hope you doing well. I'm a student in automation and control to be precise. My project is PID control using labview, and I went through many papers trying to build my VI but still facing problems and I do appreciate if could help me with it.
  
First, the project lies on the standard labview 8.2 which available in the computer lab and this software does not has control design and simulation or even PID control. means that I have to build my circuit on the standard LV only, So is it possible ?
  
Second, I wonder a bout adding any system I want to test my controller on, So does this version has (transfer function) to test the controller?
  
Thank you and looking to here from you .

[Jochen]

saed,

for systems with low dynamics (e. g. temperature control) you can use standard LabVIEW on a Windows platform, but if you plan to control a system with higher dynamics (e. g. a DC motor), this is not a promising approach as Windows (or Linux) doesn't provide deterministic = stable loop timing. The timing accuracy of a control loop is at least as important as finding proper PID parameters. If you want to learn more about real-time control and deterministic execution of LabVIEW code, please refer to this link.

I'm sorry, but I don't understand this sentence:

"Second, I wonder about adding any system I want to test my controller on."

 Are you looking for simulation capabilities?

Kind regards,

Jochen Klier

National Instruments

[saed]

Thank you for your reply, I understand from the message that applying DC example is difficult ?

and answering your question, I would yes, I want demonstration and simulation only. So is it possible whether I have temperature on DC system ?

[saed]

I have done somehow what I would share with you and please have a look  on it. I just don't know if I'm right or wrong ??

and I what a good example could've been good to test .... I can't decide

[Jochen]

saed,

I didn't say that any kind of DC system is difficult, but controlling real systems like DC motors or any other kind of system with high dynamics requires deterministic behavior of your program. If you are only looking into software simulation, real-time behavior is not a requirement.

Your vi looks like a very basic implementation of a PID controller but it's not  executable, as all loops stop immediately after starting the execution and there are many basic programming issues that I can't address in a forums thread.

I think the best advice I can give you is to first learn more about LabVIEW programming by either reading one of the many available books or byvisiting a training class. Writing your own PID algorithm at that stage is really not recommended. The PID control toolkit is part of each academic bundle, so it might be worth double checking if it's really not available at your university. Besides the PID control palette, this toolkit ships with a lot of good examples that should help you getting started quickly.

Kind regards,

Jochen

[saed]

Thank you Jochen for your reply. I appreciate it .

I think if you put any values for the each empty numeric componant you will see it work. and about the toolkit I know that I can get the benefit for using PID Control toolkit . But I've been asked to do it on standard one which in computer lab.

thank you and I will let you know for any new.

[saed]

I just don't know i can't step forward.:mansurprised:

[saed]

Hi all what is the equivalent term to Zero Order Hold (ZOH) in Labview? . I Know this in matlab but not on labview.  

[Jochen]

saed,

you better should post this type of question in a new thread to the LabVIEW forum as it is not directly related to motion control issues. You should post questions to the motion control forum if they are related to motors, drives, motion controllers and so on.

Jochen