Matlab DLL

I was wondering if somebody help me how I can use Matlab dll (creating in Matlab 7) in LabVIEW. Many thanks

The Matlab exports an ActiveX element. So you have to register first this DLL and then call it.
At the test.vi which is attached you can find the way to call it.
1) Select the desired matlab class (At the diagram right click the Automation constant and choose the select option)
2) Call the Method / function
3) Close the Class
The vi is broken beacuse you have to select the desired method.
There are 10 kind of persons. Those who understand binaries and the others.
Attachments:
test.vi ‏11 KB

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I would like to convert a matlab file into a .dll and use it in LabVIEW. However, when I run the .dll in LabVIEW I get an error stating "... Procedure not found". What could this be? Can anyone help me...

I wish to convert my Matlab files into .dll's so that I can use them in LabVIEW. I am using 'mcc' and 'mbuild' of Matlab to convert my .m files into .c and .dll.
When I try to run the .dll's in LabVIEW, I get an error message in a modal window stating some required .dll or procedure is not found.
How should I resolve this issue. Should I add any other Matlab .dll's in course of making my .dll?
Please help in solving this issue... Thankyou very much.

KJV wrote in message news:<[email protected]>...
> When I run the matlab generated dll, it is stating 'matllb.dll not
> found'. Is it that I should set the path for matlab\bin to include
> all the dll's before I compile? When I make dll from C, it works fine
> in LabVIEW. The problem is from .m to .dll. The problem also arises
> when I convert my .m to .exe. The same error of 'matllb.dll not
> found' comes over. Should I change my matlab compiler options or
> something else? Please help me?
I have the same question,I don't know how to use the matlab DLL file in labview,
I hope someone can descripe the procedure in detail.

How to use matlab compiled DLL in Labview ?

I have LV 8.5, and am unable to use a matlab compiled DLL in my LV code. I have tried the 'import' command, but it does not list any functions. However, it does not show any errors during its execution. The existing solutions/responses to this question do not work either. I would also like to know of a way to deal with mxArray datatype. What is its equivalent in C (or any other high-level language) ? How do I retrieve an array that is returned from the matlab dll ?

I'm assuming you have either Matlab installed or at the very least the Matlab Runtime, otherwise the DLL won't work. The "import" command relies on having a header file. Do you have one? You also need to make sure the DLL has been compiled so that it's compatible with LabVIEW. The most likely problem is name mangling, which also occurs when you try to compile a DLL written in C++. See this post, which contains links to useful posts.
The mxArray datatype is a special datatype which is actually a structure. It's complicated. Your best bet is to create a C DLL that acts as an intermediary between the Matlab DLL and LabVIEW. If you are able to, you can, instead, simply call the Matlab code directly using the Matlab script node.

How to generate and use Matlab(R2007) .dll's in Labview

Is there a step-by-step example on how to generate and use Matlab(R2007) .dll's in Labview.
Our experimenal hardware is LabView-controlled and we want to pass
images/2d intensity arrays to a more complex matlab program that will
return an array of extracted data which we want to use in LabView again.
Thank you
Carsten

I recommend having a wrapper created around the matlab dll that converts the datatypes for you. There is a lot of fooling around with pointers involved which is very difficult in LabVIEW. btw, this got much more complicated after Matlab 7. Essentially, you need to convert your inputs into mxArrays, and then add those mxArrays to an mxArray list that you pass by pointer into the matlab dll. You also need to create a mxArray list for the outputs from the dll which you will need to extract your data out of before converting it back into a LabVIEW supported datatype. It's a big hassle. We do this pretty often, but we have created a c library that handles all the conversions, so it is feasible for us. Unfortunately, I can't share the library, but hopefully this information will help you get where you want to be.
Like I said, it would be easier if you can just get a c developer to write a wrapper for you to keep it simple in LabVIEW. Alternatively, you might try getting your m-code to work in Mathscript.
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Function calls to a dll compiled by matlab

In matlab I created a dll. I now need to access the functions within this dll from my java application.
How is this achieved?
Thanks,
Anuj.

Could you provide example code to how a method in a dll,
that wasn't compiled in java can be accessed. The method
i am trying to call is called "test" and the dll is called test.dll.You cannot call a dll directly from java, as jsalonen suggested. Instead you have to create a JNI DLL and do all the native work you wand from there.
In the native implementation of the test method you should call LoadLibrary to load the matlab dll and GetProcAddress to get the addresses of the functions that you want to call. As you can see, we have now switched from Java Programming to Windows development, so if you have trouble doing the above, then you should try to find a more appropriate forum to post your questions
LoadLibrary function:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/loadlibrary.asp
GetProcAddress function:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/getprocaddress.asp
DLLs in general
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/dynamic_link_libraries.asp
Hope these help.

Matlab vs. C DLL

I have an algorithm written in Matlab that I need to integrate into a LabVIEW VI. In our current version of the software, we use a DLL written in C that I compiled in Visual Studio through a long period of trial and error. I need to make some significant updates to our code and would much prefer to keep it in the Matlab environment that I’m more comfortable with. Unfortunately, using a MathScript node is not an option due to the complexity of the algorithm and our desired processing speeds.
Initially I thought I would buy the Matlab Compiler and use it to create the DLL, which I’d then call in LabVIEW, problem solved. However, after reading through several threads about Matlab DLLs on the discussion board, I am concerned about all of the issues that people seem to have had when trying to do this. Can anyone offer some insight into whether these Matlab DLLs usually cause problems in LabVIEW VIs or if these are isolated incidents? Do they always need to be called through a secondary C DLL? Thanks in advance!

It's been a little while since the last time I did this, but I think I can answer some of your questions. One, there's a good chance that the c-dll will run faster than the Matlab dll, unless you are using some functions that were heavily optimized for Matlab. You can use the compiler to create a dll and call it from LabVIEW, but you will have to create some sort of interface to convert the datatypes (outside of LabVIEW). You may have better luck if you use an older version of Matlab. 6.5 and prior would actually generate compiled code, and as long as you have the 90 or so dlls installed correctly, would run very quickly. These compiled dll's were also easier to call, but still require an interface to LabVIEW. Since Matlab 7 (R14), the compiled code will run exactly like it does in Matlab (i.e., with the same performance), and is easier to get compiled and running (just install the runtime). Previously, not everything would compile. Now, if it runs in Matlab, you can use the Matlab compiler to create a dll. We've created an internal c-library of functions that allow us to create and handle the pointers to the Matlab datatypes so we can work with Matlab generated code all in LabVIEW, but it is still a hassle. Unfortunately, I can't share this library.
A better option, but not always feasible is to use Real Time Workshop to create c code from your Matlab code. This can be done quickly, and will generate an actual dll that has traditional datatypes. These can be called directly from LabVIEW. Unfortunately, RTW requires Simulink and Matlab, and all of that will set you back ~$15k if you don't already have it.
Of course, there is always the Matlab script node, which works fine as long as you don't mind having Matlab installed on your test machine. This is the way we usually go for initial testing or quick demonstrations. It's much easier to modify the Matlab code this way during debugging. I'm not positive, but I think you can build an executable in LabVIEW and still call the Matlab script node, which can target a script explicitly somewhere in the file system. That way, you can tweak the "analysis" portion of the code on a built executable even without rebuilding in LabVIEW.
Finally, the Mathscipt nodes. I wish they would work, but we rarely actually get anything to work in them. The problem is that everyone developing m files does so in Matlab, not Mathscript. Then when we try to take something they've built and get it running in Mathscript we are bled to death by a million little cuts. I don't think structures or cell arrays work, and it just seems like we always run up against a little annoying thing that keeps us from using them. We are even paying for the Mathscript RT licenses now (or soon anyway) just in case someday we get something to work. I'm not a Matlab guy myself, so I can't really explain the problems clearly, but it seems like the code always has to be re-done for Mathscript, and that is not something the Matlab guys are too enthusiastic about.
sorry if I rambled a bit.
Chris
edit: wow, all my linefeeds disappeared.. FIXED

Programmable choose Matlab ActiveX DLL

Hi,
We are using Labview with Matlab ActiveX DLL. Everything work fine. But, every one we recompile the Matlab DLL, I need to re link the static reference to the new Matlab DLL. It's possible to get the link dynamic?
So, if we recompile the dll (keeping the same input, output, functionName, version), I don't need to re link my reference, only :
1) regsvr32 -u test.dll,
2) remplace the C:\Y_Code\test.dll with the new one
3) regsvr32 test.dll
I include the basic VI, the 3 different Matlab DLL (can be rename).
Test_1_0_1.dll = Add m+n+1.1
Test_1_0_2.dll = Add m+n+2.2
Test_1_0_3.dll = Add m+n+3.3
Off course, you will need the Matlab Runtime MCR7.10 (if need, I can send you the runtime, but 152Meg...)
Thank
Solved!
Go to Solution.
Attachments:
DynamicReference.zip ‏706 KB

smercurio_fc wrote:
Your question is not specific to Matlab, as it applies to any ActiveX. It has also been asked before. What you are asking for is not possible in LabVIEW. You would need to create some form of wrapper DLL that will actually interface to the ActiveX component.
Thank
How I can make a wrapper? I don't really understant what is a wrapper
Thank

Can I call .m files from a LabVIEW executable without the full development version of matlab installed?

I have an executable that I am trying to build (and distribute). Right now, it has Matlab script nodes that call some matlab .m scripts that someone else wrote. The target PC will not have the full development version of Matlab installed. Would that work? I have tried to compile the .m scripts into a DLL, but I can't import that to LabVIEW because of the special Matlab types (*mxArrays). I have also tried to write a wrapper around that DLL, but with no success. So now I'm wondering if I can either call the Matlab .m scripts directly from a Matlab Script node OR if I can call my Matlab DLL from within a script node. OR any other idea someone might have...
Thanks a lot!
-Matt Bradley
************ kudos always appreciated, but only when deserved **************************

Simon,
I looked at MathScript and am considering using it, but one thing that is not clear to me is if I will be able to use my .m files like I can with Matlab. I call the same Matlab script repeatedly and it keeps track of some information in global variables (for example, the number of consecutive detections). Can I do that entirely within mathscript or would I have to reload all of the info each time -- if I had to do that, it would mean substantial changes to the .m files ... and that's not an option.
-Matt
-Matt Bradley
************ kudos always appreciated, but only when deserved **************************

Matlab script no longer works after upgrade of matlab

First of all im using labview 7.1.1 to execute a vi which uses some labview scripts to do the bulk of the number crunching and labviews excellent interface.
The problem happened when i recently was forced to use Matlab 7.1 R14 SP3 because some of my other routines required this. After i had upgraded matlab and tried to run the labview vi, all i keep getting is an error no. 1050 from the matlab script object.
Now the most infuriating thing about this is that it is such a non descript error, i mean , what does it actually mean? and as such i dont even know where to start in solving this problem.
Has anyone solved this problem or indeed had it themselves, im at the end of my tether with it now.
Thanks for your help
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This is a known problem between different version of Matlab and LabVIEW. Mathworks changed the Matlab interface with version 7, which broke a lot of LabVIEW code. Which version of Matlab were you using before? You can try searching these forums for "matlab error 1050 labview" and you'll see what I mean. Typically he problem is the version of the matlab.dll that's in the LabVIEW installation directory. You can try the stuff suggested in this article.

Using Matlab in Labwindows/CVI

I have a matlab .m file that runs a function. In my Labwindows software, I want to be able to run this function. Is this possible? Thanks.

Hi Kamkon,
Have you had a chance to look into the example posted by Anna? I've come across discussion forums regarding how to use MATLAB dlls in LabWindows CVI. They are listed below. I hope this is of some help to you.
http://forums.ni.com/t5/LabWindows-CVI/How-to-use-a-Matlab-DLL-in-CVI/m-p/548105?requireLogin=False
http://forums.ni.com/t5/LabWindows-CVI/Linking-Matlab-generated-lib-files/m-p/283814?requireLogin=Fa...
Creating a MATLAB dll is somewhat outside the scope of our suppot. However, I have found a third party link on this topic. Hopefully, it will point you in the right direction.
http://www.mathworks.com/support/solutions/en/data/1-18CBI/index.html?solution=1-18CBI
Regards.
Josh L.
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National Instruments

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Hi,
Does anyone know how to completely integrate Matlab functions into Labview program without a copy of Matlab in the system when I run the entire program?
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hi smercurio,
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Bob Young - Test Engineer - Lapsed Certified LabVIEW Developer
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Query: Does anyone have experience of calling compiled MATLAB functions from a LabView Executable?

Hello
Well, I am using some applications as you ask. Some calculus was done in matlab, so, now, it is compiled as dll an front end and other calculatiosn are in Labview. matlab dll are registered as activex, and so are called from labview. Integration is so good, tha some old matlab application was changed to Labview and matlab dll.
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Cheers
Alipio
"Qod natura non dat, Salmantica non praestat"

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Hi,
I would like to create a pulse with the ni usb-6259 counter via Matlab (R2007b). As Matlab Data Acquisition Toolbox dosen't support the access to the counter/timer of the 6259, I call 'DAQmxCreateCOPulseChanFreq' from the library. However, it returns a negative status indicating that the channel was not created. Can someone tell me why I have a negative status?
Thanks,
Miko
Here is the code:
% %load libraries nicaiu.dll,nidaqmx.h if not loaded
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'C:\Program Files\National Instruments\NI-DAQ\DAQmx ANSI C Dev\include\nidaqmx.h', ...
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%define required properties for pattern generation
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nStatus = calllib('myni', 'DAQmxCreateCOPulseChanFreq',...
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Miko

Thanks Peter!
It indeed proved useful, thanks to the last comment (slastuka p.10).
It seems that the input and output type depend on NIDAQmx version.
Here is the code (that works for me), in case help someone else:
clear all, close all
clc
if ~libisloaded('myni')
disp('Matlab: Load nicaiu.dll')
loadlibrary('nicaiu.dll', ...
'C:\Program Files\National Instruments\NI-DAQ\DAQmx ANSI C Dev\include\nidaqmx.h', ...
'alias', ...
'myni');
end
disp('Matlab: dll loaded')
% libfunctionsview('myni')
% Counter must be driven and read through 'c' function calls
% Define variable for taskhandle
Taskh1 = [];
% Create task
[a,b,Taskh1] = calllib('myni', 'DAQmxCreateTask', 'Counter', Taskh1);
Taskh1 = libpointer('voidPtrPtr',Taskh1);
% Create channel name for counter input edge count
Taskchans1 = libpointer('cstring','Dev1/ctr0');%Counter name
NameChan = libpointer('cstring','');%Channel name
%define required properties for pattern generation
DAQmx_Val_Hz = int32(10373); % Units: Hz <-> 10373
DAQmx_Val_Low = int32(10214); % Resting state: Low <-> Terminal is at a low state at rest. Pulses move the terminal to a high state.
InitialDelay = 0; % Delay (sec) from the start call to the beginning of the pulse train ; this is currently set to 0.0 by default.
Freq = 16000; % Hz
DutyCycle = 0.5; % width / period. This ratio, combined with frequency, determines pulse width and intervals
% Create channel: specify duty cycle and frequency
nStatus = calllib('myni', 'DAQmxCreateCOPulseChanFreq',...
Taskh1, Taskchans1, NameChan, DAQmx_Val_Hz, DAQmx_Val_Low, InitialDelay, Freq, DutyCycle);
if nStatus == 0 % channel created successfully
disp('Success')
elseif nStatus < 0 % error: channel not created
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elseif nStatus > 0 % channel created with warning
disp('Warning')
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I don't know for the following, but at least I can create the channel.
Miko

Included DLLs path, call library node

Hi,
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