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Exponential transfer function

I'm trying to recreate a system that controls the MAP using a PID controller by varying the PID parameters to modify the infusion rate signal, but the output of the system is the same as the input which I actually think is because the transfer function is not working. Here is my block diagram and the results.

I went through some discussions here and non of them solved the issue. I currently use the MathScript  block to write the transfer function. This is the outputThis is the output

 

This is the block diagramThis is the block diagram

 

This is the transfer functionThis is the transfer function

 

 

 

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Message 1 of 6
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Is a supposed to be a negative value?

Do you have access to MATLAB to plot the step response of your transfer function to make sure it is as you expect?

Furthermore, have you tried using a very simple transfer function in your code to ensure that would give expected outputs?

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How To Plot The Step Response of a Transfer Function
https://www.youtube.com/watch?v=b3BpSqE-nAw

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@AvatarAang wrote:

Is a supposed to be a negative value?

Do you have access to MATLAB to plot the step response of your transfer function to make sure it is as you expect?

Furthermore, have you tried using a very simple transfer function in your code to ensure that would give expected outputs?


Yes a is a negative value.

Yes I have access to Matlab and I've tried plotting the step response but I'm not sure of the output. Someone suggested that the matlab code is not right and we tried to use filter function in matlab and it works with a step response in matlab. However, when we copied the function to labview it still the same output even though the transfer function is different. 

As for you're last question, yes we've tried using simple first order TF and it works just fine.

 

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Yes this is similar to what we've tried with Matlab, but as i said were not sure about it yet.

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How does it look in MATLAB and what code did you use to test it?

Also, could we see what the response looks like using a simple TF in the LabVIEW code?

Very strange.

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