Using Control and simulation modul;e to get time resp of MISO model

[ruser]

Hi,

please can anybody show me how to find the time response of the system below using the control and simulation module??

(y(k) - 1.7407 y( k-1) + 0.6236y(k-2) + 0.1782y(k-3) ) = -0.0932 u(k-1) + e(k)

where y is output , u is input and e is white noise.

i tried to enter it into CD construct MIMO model , then connect it to CD time response .*vi s.

but do i really have to enter the model coeffs every time? and i still dont see the response!!!

please help..

regards,

ruser

[NAKeel]

Hi Ruser,

Take a look at the CDEx Time Domain Analysis example in the example finder.  That should give you a good place to start.  It gives you a outputs for various response types, so you can modify it to see the response you are looking for.

Nick Keel

Applications Engineering

National Instruments

[ruser]

Hi,

Thanks, i have tried checking the example.. but its in state space form and so when i convert my model into state space this is what i get.

I have attached it.

and i have no idea how to figure out ABCD from it because i have a discrete model.. pls help.. thanks..

is there any way to change that example so that it suits discrete transfer function MISO model?

thanks again..

 ruser

[NAKeel]

Hi Ruser,

You can get time responses from MISO models by using the recursive ARX function.  Also, check out this discussion forum.  It has a post from one of our Control and Simulation R&D engineers.  You should find it useful.

system identification miso models

http://forums.ni.com/ni/board/message?board.id=170&message.id=247429&requireLogin=False

Nick Keel 

Applications Engineering 

National Instruments

[ruser]

Hi,

i checked it out they have the same problem.. but i cant find any solutions in it..

 pls if iam not being too blonde....

could u explain how to import the model into the control module  ?

thanks again..

 regards,

ruser

[Andy_C.]

Hello ruser,

From what I've read in your posts, it seems that you were able to use Sys ID Toolkit to obtain your model, is that correct? Is the question now how to import that model into Control Design? You should be able to use SI Convert to Models of CDT VI to convert the model estimated by Sys ID into a model that you can use in Control Design. The thing to note is that the model would be in discrete form, so you may want to convert the model to continuous depending on your application (shown below). Let me know if this helps!

[ruser · Accepted solution]

Hi,

U have got the correct picture.. i used the sys ID toolkit ( assistant).. for estimating the system model..

and i have been trying all last week to get my system model into labview for using the control module on it.

Alhamdulillah...

I finally got it done... I saved the model into a file from the sys id toolkit.. (my model is in discrete form)then i loaded it into labview using the load model from  file ..

so now i have it in labview..

now for the control parts...:)..

thanks again..

 ruser.