control and simulation

[nolsqn]

Hi Guys, 

I am trying to simulate a smith predictor. Its a normal example with my transfer function. The the output of my plant doesnt seem to increase more the 3 and I have no idea why. 

Maybe any one can tell me what I am doing wrong.

Best Regards, 
Ali Asad

[CorinneDoppmann]

Hi Ali,

In order to find the problem with your program I have a few questions and comments:

- Strictly speaking you should put the initialization part of your vi into a sequence structure, else you can not guarantee that the transfer functions are calculated by the time the simulation starts running, and you may receive simulation errors.

- In the image below, shouldn't there be a minus, where the red arrow is pointing to?

 

- When you try to run the program, which values are you using for the Numerator, Denominator, SetPoint, KC, TI, TD and Delay?

If I use the values as shown in the vi you sent, I don't receive the same transfer functions as you. For example the PID:

       --->            

You're PID Transfer Fct.                                        PID TF for KC=200.76, TI=6.8 and TD=20.7

- Why do you only read out one value each for "Output" and "output", that way you will only see the last value of the simulation. 

  Try using the Collector function in order to see intermediate values of the simulated output, this might help to find out, why you are not receiving the desired output values.

Best regards,

Corinne Doppmann

Applications Engineer

National Instruments