Matlab script node for real time purpose

Hi!
We are trying to control in real time the frequency of a vibration motor with a voltage signal proportional to EMG activation.
Our EMG sends data to a LAN port and we read them in Labview using the UDP Read function.
We created a VI which reads data from UDP connection, parses the header and does the decoding (according to the data type of our EMG device, TMSi Porti).
Every sample read from UDP port is passed to the Matlab script node which implements a Bayesian filter which returns a value (MAP) used to control the vibration frequency.
The problem is that this operation is extremely slow...(about 15 seconds!!) and we need it to be real time!
We tried also a simple MA filter and the delay is reduced to around 2 sec, so we think that the major problem is in the Matlab script node.
We wonder if this delay is due to the call of an external code (Matlab) or to the complexity of the Matlab code itself.
Do you know how to improve the performance of this VI?
Thank you!
Serena
Attachments:
EMGreceiver+Bayes.vi ‏54 KB

Serena
I noticed that your code also have LabVIEW MathScript RT code. Have you tried to replace the Matlab scriptnode with it? The MathScript Node compiles the script natively into G function and avoid transfering information between programs.
If this does not speedup your application, please attach the subVIs and test data that allow us to reproduce the problem and performance. Also, what is the version of LabVIEW that you are using? If it is before LabVIEW 2009, then I would strong recommend update to that version.
Barp - Control and Simulation Group - LabVIEW R&D - National Instruments

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Pxi 1042 configuration for Real-Time

I have purchased
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thanks
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Solved!
Go to Solution.

The Real-Time Deployment License is different from the LabVIEW RT module.
When you purchase a PXI controller, part of what you are buying is the operating system that is installed on it. If you purchased the controller with Windows on it then you purchased the copy of Windows that came with it. Now that you want to put the real-time operating system on it, you need to purchase the license for it.
But that's all legal stuff.
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When I use Call Library Function Node in real time, is the DLL loaded once for all or load every time it is called?

When I use Call Library Function Node in real time, is the DLL loaded once for all or load every time when it is called?
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Solved!
Go to Solution.

qing_shan61 wrote:
When I use Call Library Function Node in real time, is the DLL loaded once for all or load every time when it is called?
Once
qing_shan61 wrote:
I have a time critical real time application, in which I use a piece of DLL function developed by C++. It is OK?
OK
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Also for real-time application you need real-time OS.
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I have some software problems of running matlab script node in the LabVIEW program.

Hi there,
I wrote a simple matlab code, like x= 1, y = x*2. Then I tried to put them into matlab script node in LabVIEW.
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http://forums.ni.com/ni/board/message?board.id=MathScript&thread.id=571
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This board is for Mathscript, but you seem to have a matlab problem. You should probably post in the LabVIEW forum instead.
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Calling user defined functions in Matlab Script Node

Greetings!
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How to insert data from file into matlab script node

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Input data type of Matlab script node

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Right, arrays of singles are not supported. See Comparison of MathScript RT Module and the MATLAB® Software Data Types in LabVIEW
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Matlab syntax errors are not caught and reported when code is executed in a LabVIEW Matlab script node

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Attachments:
matlab.vi ‏13 KB

I ran your example VI and the is what I got in the Error Out cluster:
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I cannot run the matlab script node in the labview

Hi there,
My LabVIEW version is 8.5, and matlab version is R2008a.
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However, when I ran the program, I couldn't run and Labiew show some error.
Then I tried the method talked before on this forum. Please see the following link.
http://forums.ni.com/ni/board/message?board.id=MathScript&thread.id=571
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Hi, and thanks for the post! I hope your well today.
This may help,
MATLAB® version 2006b (7.3) and version 2008a do work with LabVIEW
8.20. This problem can occur if a new version of the MATLAB® software
is installed along with a previous installation, which is then
uninstalled. The uninstallation of the older MATLAB® software results
in removing the ActiveX/COM components LabVIEW uses. This can cause the
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solutions to this problem.
Uninstall the MATLAB® software and reinstall it. This should install the necessary ActiveX component.
Restore the MATLAB® automation server. Browse to the \bin directory (e.g. MATLAB\R2006b\bin) and type matlab -regserver ,
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contain MATLAB® script nodes.
Leave both versions of the MATLAB® software installed.
MATLAB® is a registered trademark of The MathWorks, Inc. Other
product and company names listed are trademarks and trade names of
their respective companies.
Did you have an older version of MATLAB before 2008a?
Kind Regards,
James.
Kind Regards
James Hillman
Applications Engineer 2008 to 2009 National Instruments UK & Ireland
Loughborough University UK - 2006 to 2011
Remember Kudos those who help!

"Waiting for real-time target (RT PXI target) to respond" error when the program waits interrupts

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I have developed an application to detect interrupts generated by a electronic card and act in consequence. The program has been developed in labview but it calls a dll; that was created with labwindows. The dll is programmed to open the visa communication, enable events and install the interrupt handler and when an interrupt is detected, it reads the value of the different registers of the card and returns it to labview to visualize them.
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Solved!
Go to Solution.

Hello Naity,
First of all, in which thread runs the waiting process? Is it scheduled in another thread than the function setting the flag?
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In labview, I call the function interrupt with a call library function node (see the capture attached) and the program reads and saves the data from returned from the function.
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I've never used events before in labwindows but I will try to do it in this way. But anyway, I suppose that I should; somehow, wait the event to occurs in labview while the waiting for the event is programmed inside the dll...and probably the same prompt that i am trying to avoid is going to appear again, because I am not returning the "control" to labview (I mean, labview executes the dll and waits for the event to occur. Then the execution of the labview program is stopped in the call library function node executing the dll)
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Attachments:
capture.png ‏40 KB

Error 1050 by trying to use load'filename' in matlab script node

Hi
I keep getting error 1050 when Labview tries to load a text file through the matlab script node.
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Solved!
Go to Solution.
Attachments:
matlab.jpg ‏213 KB

Yes I forgot, this is my error... It looks like it can't read the file path, but the 'file' path is actually just a path to my c:\user\*\*\*\*.txt
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MAX support of SNTP for Real-time controllers

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