Numeric Operations with transfer functions

[shank]

i will see into it and let you know.

thanks a lot till then sir.

[shank]

Dear Sir,
    I have ordered the Simulation Toolkit and will get it very soon. By that time i would just like to take a view at the block diagram I am trying to model in LabVIEW. If you want I can also attach my model which I have tried using Control Design Toolkit. Pleas take a look and suggest me if this modelling is possible with labvie or not, and if yes which other toolkits i need to buy.

Thanking you a lot again,
Waiting for your prompt reply,
Shashank.

[Barp]

Shank,

This is a typical application where you would like to use Simulation Module. Every element in that diagram have its own version if Simulation, like the Integrator, the lookup table, the transfer functions and all the operators.

You could try to use Control Design, but you would need to do a lot of work to allow feedback node to work properly. Notice that Feedback node in LabVIEW will need to be broken with shift registers. On the other hand, LabVIEW Simulation will generate the code necessary for your simulation to work. Please look at our documentation online.

http://zone.ni.com/reference/en-XX/help/371894B-01/lvsimhowto/sim_h_gs/

Are you planning to do experimentation to obtain the parameters of the transfer functions or delays? In this case, I also advice you to look into the System Identification Toolkit. It allows you to convert signals acquired to parameters in the transfer function. Look at this manual for more information:

http://digital.ni.com/manuals.nsf/websearch/6A0CD9680459E0C4862571A80008D9F3

This should allow you to get up and running very soon. Let me know if you have more questions!

[Barp]

One more think, Shank. Notice that we have to Products that deal with Simulation: The Simulation Interface Toolkit and the Simulation Module. They are 2 different products: the first one allows you convert models from other software like Simulink® to LabVIEW. The second allows to directly create the diagram that you send in LabVIEW. So, please verify that you ordered the Simulation Module (or Control Design and Simulation Module for LabVIEW 8.5) instead of the Simulation Interface Toolkit.

[shank]

thanks a lot sir. i have already received it and i am currently installing it. will give it a try. it would be of great help if you can show me a bit how to use it , for example by designing a small part of it if you can. for example i didnt get the thing that why there should always be a signal generator with a transfer function? the model i have provided gives nothing like that. still do i have to use it alwys?
 thanks again for all your help.

[shank]

or else should i attach the model i have designed with control deisgn toolkit. maybe you can find out some errors in it.

[shank]

Dear Sir,
        I am attaching my model with control design toolkit hereby. also if i try to copy paste the lookup table in the simulations loop then they becomin floating and then i cannot wire them properly. can you telll me what my problem is. waiting eagerly for your reply.

thanking you,
shashank.

[Barp]

Shank,

First of all, you SHOULD use the Simulation Module to develop the transfer functions. The VIs that you are using with Control Design are designed to be used offline and you can only use them when you have the complete transfer functions.

So, I am adding a possible translation of your diagram that you sent me before in Simulation Module. I did not change all the values to match your diagram, but I modified some. Notice that you have to use the Simulation Loop to allow dropping the simulation nodes inside. Notice also that Simulation Nodes don't allow you to be dropped outside Simulation Node (at least for now). Please review the diagram in attachment with your diagram and try to match values and see you can make your simulation to work.

Hope this helps!

[shank]

thanks a lot sir,
    i almost did the same thing. i hope it works now. a few additional things i need to do then it will be done. only i wanted to ask you that if i am using a square wave generator how to change its duty cycle? remaining stuff is exactly the same as you gave.

thank a ton for all the help support and patience too.
thank you.

[Barp]

Shank,

I am happy that you are making progress with your project. You see how easy and legible it gets with Simulation? It becames much easy to fix problems with this project now.

Now, if you want to change the duty cycle of your signal, you can do with "Pulse Signal" function. And you make it parameter to come from terminal (Open the configuration with double click on the "Pulse Signal" and after selecting the "duty cycle" parameter, select "from terminal". That should allow you to change the value on the fly or, at least, change from the terminal.

That should be enough... Now, if you don't mind ask, are you trying to do biomedical research? Are you planning to run with DAQ? Actually that should be easy to put together once you have the simulation working.