Using dll in labview realtime

Hi to all,
I would like to know the best way how to open a file DLL in labview.
I created this dll with matlab, real time-workshop, nidll.tlc
after that I have to use these dll in a real time VI, for using that into a cRIO,does it exist a tutorial in order to explain the procedure?
thank you

No it is not! As it uses Cygwin to port the Gnu Unix tools so they can run under Windows. Cygwin is a great tool but had always a hard time to run on newer Windows versions than what was released at the time a particular Cygwin version was created.
The VxWorks versions that NI used for their realtime controllers is very old. There is no hope that someone would go through the trouble of trying to backport the Cygwin bugfixes since that time to this Gnu toolchain, nor has VxWorks any interest in creating a new Gnu toolchain based on modern Cygwin and Gnu tools for older VxWorks versions.
NI has moved since away from using VxWorks. In fact the only reason they went with VxWorks, was because Pharlap ETS was not compatible with the PPC CPU and at that time the choice in powerful x86 compatible CPUs for embedded applications was VERY small or actually non-existent.
As you can see Open source observes similar rules as commercial software. Don't spend much time in trying to make old stuff work on new versions. In fact commercial software usually makes a lot more effort to be portable across different versions. In Open Source the general tenor is, I want feature X, that requires GCC Y, which will only work with glibc x.z.v. Don't spend time in trying to make any of these work with older versions too, or update older applications to work with newer OSes etc. If you want Windows 7 or 8 you have to have Cygwin 1.7.something and that will usually require GCC 4.something and a myriad of other dependencies. The gnu toolchain for VxWorks 6.3 which is used on the NI controllers since LabVIEW 8.5 uses GCC 3.4.4.
Considering that LabVIEW 8.5 was released in 2008 and the VxWorks tools to create the OS for the controllers obviously even quite some time before that, but Windows 7 RTM was only in July 2009, there is not much you can complain about the fact that those tools do not run on Windows 7 or 8.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

Similar Messages

How to use dll in Labview ?

I compile this code to dll file with VC++2010 filename is test_dll.dll .
#include "stdafx.h"
#include <iostream>
#include <Windows.h>
using namespace std;
int main(int a){
cout << "Test dll...............\n";
return a;
After that, I put Call Library Function node in editor and double click Call Library Function node. I browse test_dll.dll into Library name or path and set function prototype to int32_t main(int32_t a); but it show error Call Library Function Node 'test_dll.dll:main':function not found in libraly. How to use dll in Labview ? And I have more question is what is differrent from Tools -> Import -> Shared Library(.dll) and use Call Library Function node.
Solved!
Go to Solution.

The issue you are having is that LabVIEW is not capable of using C++ DLLs directly. It only handles C DLLs. This does not mean that if you you cannot use the DLL if it's compiled with the C++ compiler as opposed to the C compiler. Rather, it means that you must take extra steps in order to use it from LabVIEW. The primary issue is that of name mangling or adornment. This is discussed here: http://zone.ni.com/devzone/cda/tut/p/id/4877. Basically you need to prepend extern "C" in front of your prototypes in your header files. I would also suggest reviewing this article: https://decibel.ni.com/content/docs/DOC-14564.

How to make a driver using DLL in LabVIEW?

I had followed the "Using Exteranal Code in LabVIEW" manual having finished the making dll file, and the lsb file(I attempted that two ways). But when I load the code in LabVIEW, it can't work. I don't know what had happened, I only got a error message like this:"'0x100014f1'commond call memory'0x00000000',this memory can't be written" or other similar error message, if I push the "enter" button, the vi application which I having lunched will crash. If I push the "cancel" button, the debug model will start,and the next message is "Unhandle exception in LabVIEW.exe(MSVCRTD.DLL/LVS95.TMP/COUNTER.DLL(the last one is creat by myself)):0xC0000005:Access Violation", but I wonder what had cause this? My DLL had been made successf
ully under the VC++6.0, why LabVIEW can't call it fluently? How to make a driver for my own device using LabVIEW? How to correct my error to finished my hole work? Thank you very much. Jacky Wei
Attachments:
counter1.rar ‏33 KB

1. Can you call this DLL from within VC?
2. What operation system do you use? There may be a problem with calling of win95 dll under NT or win2000 for example.
3. If you use NT you may not have permissions to work with some ports and memory areas.
4. Under NT or win200 try to compile the library as a 32-bit dll, and under win95 - as 16-bit one.
Good luck.
Oleg Chutko

Collecting data from hardware using dll

Firstly I d like to say hello, im the very beginier to labview thus I appeal for some patience.
There were many threads dealing with that issue, I tried to get information from each one of them.
and I posted this mesaage in order to make sure if i `d got it well.
Well I ve got hardware and want to gather data from it, (its not array but 3 (variables?) and of course it has its own dll.
What am i supposed to do is?:
1.write other dll (VS) and there is asynchronous callback to device to get its position just like in exec aplication.
2. USe PostLVUserEvent() to make parameters familiar to labview (in dll)?
is that correct way of thinking ?
I dont have problems with using dll in labview, but I dont know much about how asyncrhnous callbacks works with dll
I hope its all clear.
I know the all answers are here but I d like to summarize it, especially that I could miss something.

There is dll (api?) provided by drivers(generally speakin) with all functions needed and documentaion, and second dll written by me with imported this finctions , which actually isnt a wrapper, but only c dll.
Code was rewritten and divided (compared to previous one) to 3 functions in order to avoid loop... and there is no callback anymore , ...... but called from labview one by one these functions are running very slowly - otherwise from the exec application that I made to test dll. I hope its understable enough .
I think documentaion isnt necesary.
JakubFrr wrote:
HDCallbackCode HDCALLBACK GetDeviceStateCallback(void *pUserData) // - it was getting state before,now code`s changed beacuse of the while loop .. now it does nothing and I ve just noticed that its not necesarry
return HD_CALLBACK_CONTINUE;
void init()
HHD hHD = hdInitDevice(HD_DEFAULT_DEVICE);
gCallbackHandle = hdScheduleAsynchronous(
GetDeviceStateCallback, position, HD_MAX_SCHEDULER_PRIORITY);
hdEnable(HD_FORCE_OUTPUT);
/* Start the haptic rendering loop */
hdStartScheduler();
void work(float *a,float *b,float *c){
hdBeginFrame(hdGetCurrentDevice());
hdGetDoublev(HD_CURRENT_POSITION,position);
(*a)=position[0];
(*b)=position[1];
(*c)=position[2];
_sleep(50);
hdEndFrame(hdGetCurrentDevice());
void disable()
hdStopScheduler();
hdUnschedule(gCallbackHandle);
hdDisableDevice( hdInitDevice(HD_DEFAULT_DEVICE));
I used pointers with simple functions dll like adding etc. before and it worked fine.
I admit I dont exactly get callbacks. Its seems I can manage without them now, but I`m aware that during more complicated 'operations' it would be much harder. Now it works in labview but very slowly...
nathand wrote:
(makes the appropriate call to the original DLL, passing the address of the callback function).
Could you give tutorials/example/explanation?
With best ragards

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 a C# dll in Labview?

How can I use a C# dll in Labview 8.2? With the "Import Shared Library" Wizzard I need the header file which I don't have. Is there another way
to use such .dll to import the functions created in C#?
Thanks in advance
Norick

Norick,
afaik there is no tool which provides you the possibility to create something like an instrument driver for .NET assemblies.
Maybe we should take a look into terminology:
- Instrument driver: This is a set of functionality, which provides the user with an easy to use API for a special instrument. Very often, the driver itself is written in C/C++ and provided as a DLL.
- "Import Shared Library" Wizard: This wizard enables the user to create an own API for any C/C++ DLL (or compatible) for LabVIEW. This wizard requires the information on all exported functions; this info is contained in the header file. The result of the wizard is a set of VIs containing one Call Library Function Node each for each exported function.
- .NET assembly (extension .exe OR .dll): This can be compared to ActiveX. So the way to program with .NET is similar to ActiveX. Maybe you want to take a look into the examples of LabVIEW regarding .NET...
- Global Assembly Cache (GAC): All assemblies contained here are registered in the system. Every application can easily work with assemblies contained here.
- Private assemblies: This would be the way to work with .NET assemblies which are built on your own. You have to select the .DLL-file itself and make sure that the file can always be found in the same (relative)folder of your application.
hope this helps,
NorbertMessage Edited by Norbert B on 02-21-2007 02:16 AM
CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.

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.

Creating a DLL in LabVIEW containing a function using pointer to pointer

Hi!
I´m facing the problem to create a DLL from LabVIEW containing the following C-function:
functionF(structS** arrayA) ,
where:
structS is a struct of various data-types (e.g. int)
arrayA is an C-array of structS
How can this be done? Any ideas?
Thank you in advance for your support

This cannot be done in LabVIEW. LV doesn't have the data type "Pointer" as C has.
The only workaround I can think of is to use an array of strings in LV and in the interface define the parameter as "by reference". In LV you have to typecast the wire with the string to a cluster withthe layout of structS.
As far as I know an array of strings is represented as an array of pointer to strings. This is because strings are variable in length and therefore LV uses this method storing the pointers to the strings in the array and not the elements as usual.
You have to read the document about memory and data types of LabVIEW. In elder versions this was in the LabVIEW Bookshelf but I haven't found it in short in the newer version.
Waldemar
Using 7.1.1, 8.5.1, 8.6.1, 2009 on XP and RT
Don't forget to give Kudos to good answers and/or questions

Build a DLL in LabVIEW & Use the DLL in LabVIEW

I am trying to build a DLL for the simple vi with LabVIEW and want to use the DLL in LabVIEW. is it impossible?
I wrote a vi and it have 2 terminals. one is the input for numeric dbl data type and one another is the output for numeric dbl 1D array data type.
It was built with the Application builder for LabVIEW 8.0 and DLL was created successfully.
I want to use this DLL in new vi with LabVIEW.
Call library function used. I wrote a new vi to use that DLL.
In config dialog I config each parameter for dll and connected terminals. but it doesn't work
pleas refer to the attatched file and let me know what I missed.
Attachments:
Array1D.zip ‏60 KB

At first I kept scratching my head wondering why someone would want to do this. Create a DLL in LabVIEW to call it from LabVIEW. Seems redundant. But, perhaps it's an exercise or perhaps it's for testing the DLL...
In any event, calling the DLL worked for me in 8.2. How are you configuring your Call LIbrary Function node? I have it set up as follows:
return type: void
iteration: Numeric, Signed 32-bit Integer, pass by value
array1D2: array type, Signed 32-bit Integer, 1 dimension, "Array Data Pointer" format
len: Numeric, Signed 32-bit Integer, pass by value
Then I called the DLL like this:
Message Edited by smercurio_fc on 03-16-2007 12:57 PM
Attachments:
Example_BD.png ‏2 KB

Using a cygwin DLL in LabVIEW 7.0

Hallöchen!
I try to use a function from a cygwin DLL in a LabVIEW 7.0 VI. So
I wrote
void funcName(double values[], long number_values)
for (int i=0; i < number_values; i++) values[i] /= 2.0;
to the file test.cc and said (cygwin gcc 3.3.1)
gcc -c test.cc
gcc -shared -o hall.dll test.o
Then I included it as a shared DLL in LabVIEW, added the correct
parameter sequence and return value. The name of the function was
a little bit different (Z8funcNamePdl).
But: LabVIEW crashes every single time. Not matter what I say about
calling convention or reentrance. As soon as the "configure" window
is closed, *all* LabVIEW windows are closed.
What am I doing wrong?
Thank you!
Tschö,
Torsten.
Torsten Bronger, aquisgrana, europa
vetus

Hallöchen!
LarsRoe writes:
> [...] LabVIEW arrays have a different structure than the
> traditional C arrays. As a quick test, try passing in a single
> DBL value by pointer for the first argument, and 1 for the second
> argument.
Even a "void Test()" lets LabVIEW crash. I now say
extern "C" {
void Test();
void Test() {
return;
> The prototype in your C function needs to match the prototype you
> get from the "Create C File..." Dialog.
Granted, but quoting the gcc manual: "Good compilers never crash."
I didn't *start* the VI after all.
Tschö,
Torsten.
Torsten Bronger, aquisgrana, europa vetus

Using DLL functions created with LabVIEW 6i in CVI 4.0.1

I want use SQL functions from LabVIEW 6i in LabWindows/CVI 4.0.1. Building DLL with this LabVIEW-functions was succesfull, but after using DLL in CVI project and run, error message was generated: FATAL ERROR : LABVIEW.LIB was not called from a LabVIEW process. Can you help me? In attachment are VIs and build script for this DLL.
Attachments:
DLL.ZIP ‏24 KB

The SQL toolkit appears to be an ActiveX program. Why not call the objects with activeX in CVI directly?
There are several hits for labview.lib on ni's site. Goto http://search.ni.com/?col=alldocs&layout=TechResources&ql=a
and search for labview.lib.

How to access Call Back Functions using *.dll in the Labview?

Hai,
I am Pavan Ram Kumar Somu.
I am new to Labview, currently I am working on MVB Interface.
I need to access the API functions from *.dll file in Labview, as of now , I am doing this with Call function Library node in Labview but it does not support the following data types like
    1. Pointer Arguments(To which memory it points in Labview)
    2. function pointers Arguments
    3 .pointers in structures and pointer structures in structures and many other data types.
Please Answer the below queries also:
1. How to pass pointer arguments to API functions in DLL and how to collect pointer
    return types from API functions in DLL
2. How to pass structure arguments to API functions in DLL and how to collect structure
    return types from API functions in DLL
3. How to use callback functions(nothing but function pointers) in Labview and how to
    collect callback fuctions return types from API functions in DLL
I need your help while passing these datatypes to API functions in DLL from labview.
Suggest me if there is any other alternative for implementing this task.
I am referencing some examples here:
Examples:
I)
Unsigned short int gf_open_device(void *p_device_config, unsigned long int client_life_sign_timeout, unsigned short int *device_error)
void *p_device_config: How to access/pass these arguments in LabView and to which memory location it points in LabView.
II) #include <windows.h>
     #include <process.h>
     HANDLE rcvEvent0, rcvEvent1;
/* Function call*/
CanGetReceiveEvent(handle[0], &rcvEvent0);
Above is a piece of C code, Now I want to use HANDLE datatype which is windows based, how to use these type in the LABVIEW.
With regards
Pavan Ramu Samu

"Somu" <[email protected]> wrote in message news:[email protected]...
Hai,
I am Pavan Ram Kumar Somu.
 
I am new to Labview, currently I am working on MVB Interface.
 
I need to access the API functions from *.dll file in Labview, as of now , I am doing this with Call function Library node in Labview but it does not support the following data types like
    1. Pointer Arguments(To which memory it points in Labview)
    2. function pointers Arguments
    3 .pointers in structures and pointer structures in structures and many other data types.
 
Please Answer the below queries also:
 
1. How to pass pointer arguments to API functions in DLL and how to collect pointer  
    return types from API functions in DLL
 
2. How to pass structure arguments to API functions in DLL and how to collect structure
    return types from API functions in DLL
 
3. How to use callback functions(nothing but function pointers) in Labview and how to
    collect callback fuctions return types from API functions in DLL
 
I need your help while passing these datatypes to API functions in DLL from labview.
 
Suggest me if there is any other alternative for implementing this task.
 
 
I am referencing some examples here:
Examples:
I)
Unsigned short int gf_open_device(void *p_device_config, unsigned long int client_life_sign_timeout, unsigned short int *device_error)
 
void *p_device_config: How to access/pass these arguments in LabView and to which memory location it points in LabView.
 
II) #include <windows.h>
     #include <process.h>
   
     HANDLE rcvEvent0, rcvEvent1;
 
/* Function call*/
CanGetReceiveEvent(handle[0], &rcvEvent0);
 
Above is a piece of C code, Now I want to use HANDLE datatype which is windows based, how to use these type in the LABVIEW.
 
With regardsPavan Ramu Samu
Search the forum (forums.ni.com) for callback, pointer or handle, and you'll find that it is all possible, but not very easy.
e.g.: http://forums.ni.com/ni/board/message?board.id=170&message.id=88974&requireLogin=False
Regards,
Wiebe.

Using Labview realtime module in RTAI

hello everyone,
i want to use Labview realtime module in RTAI for real time applications beacuse of it's free source and very good performance. is it possible to do this work?
if it is, can anyone introduce some same case study or something similar to this?
Solved!
Go to Solution.

amirsaman wrote:
hello everyone,
i want to use Labview realtime module in RTAI for real time applications beacuse of it's free source and very good performance. is it possible to do this work?
if it is, can anyone introduce some same case study or something similar to this?
I don't think that is possible for anyone outside NI. LabVIEW realtime supports at this time only Windows as development host and as target only National Instruments hardware with specifcally targeted OSes or the Pharlap ETS system on x86 systems with a somewhat specific hardware configuration. Using RTAI as target OS for LabVIEW realtime applications would require first some modifications to the LabVIEW realtime plugin to support this new platform.
Also none of the LabVIEW realtime files created for either the NI platforms running VxWorks or Pharlap OS, or the Pharlap ETS system woud be possible to get deployed to a RTAI system, as they are not compatible. You would in the first place have to port the whole slew of shared libraries that make up the realtime LabVIEW runtime system on one of these targets to your RTAI system which is basically a completely new LabVIEW target platform that you can only create with quite a bit of effort from the LabVIEW source code. It's not really impossible for NI as most of the LabVIEW code is written quite platform independently but it would be a combination of the compile settings for current LabVIEW realtime, with settings to produce LabVIEW VxWorks realtime targets with some extra Linux settings. Yet it would be by far not trivial and some of the parts are actually hardware specific drivers which have to be ported too, and limit the possibility of what RTAI hardware could be used even further. In short not something that would make any commercial sense to NI as they would have to invest a lot of resources without any possibility to sell extra hardware.
And hell is freezing up before NI releases LabVIEW source code in any form that would give non-NI employees access to it!
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

Using gpib-32.dll in Labview 7.0

Hi there,
I am relatively new to Labview and I need some help trying to program an old HP3488A switch/control unit using the Call Library Function Node. I would like to convert the existing VB6 code, which uses gpib-32.dll, into Labview. What I have done in the VB code is to call the ibdev function to set up the HP instrument. I would like to do the same in Labview. How would I even go about setting up the .dll files as I am revamping the existing code (running on a Pentium II computer) and trying to create an identical code in Labview (running on a Pentium III computer). Also, after I have set up the .dll files (done any system configurations if necessary), how do I actually implement this file in Labview?
I have tried calling the ibdev function in the properties of the Call Library Function. I created 6 parameters of return types with ranges of type long. Then I pass integers into the input of this node and when I tried running it I get an error exception within the external code as follows:
"An exception occured within the external code called by a Call Library Node. This might have corrupted Labview's memory. Save any work to a new location and restart Labview. VI "switch.vi" was stopped at Call Library Function Node 0x1D7C of subVI "switch.vi"
Can someone please help me? Thanks.

I actually tried that before. As the HP3488A switch instrument is very old and came out before IEEE488.2 got introduced, it still uses IEEE 488.1, or HPIB commands. When I try using MAX or even my Agilent IO Control, it shows that there is an instrument connect to GPIB address 10, but neither programs can auto-identify the instrument using the *IDN? query. Even so, I tried typing ID? in both programs and I got no data back from the instrument. I'm not too sure as to what the problem is since I always get "\n" back from the instrument's reply. I even tried changing the termination character enable to TRUE and I still got nothing back.
However, on the front local display of the switch, I can see arrow indicators moving between TALK and LISTEN whenever I perform a write or write/read command. But no data gets sent or received because I couldn't perform any write commands to change the switch. If anyone can tell me what the real problem is that would be great. But if not, then I will have to use the Call Library Node because I know that my VB6 code actually works on the HPIB instrument and I could simply use this gpib-32.dll file on Labview and perform the same instructions, which should allow me to talk to the switch. Can anyone tell me how to properly set up a Call Library Function Node as I have errors using the gpib-32.dll file (please see my previous message)?

Using Keyboard or Mouse in LabView RealTime

Hi,
I would like to know whether keyboard or mouse can be used as input in LabView RealTime. If yes, can anyone explain me how to get the input coming from the keyboard or mouse?
Thanks

Hi e_Rik,
Could you explain what you are trying to do a little further? Currently the only real-time targets that can have a keyboard or mouse plugged into them is a PXI chassis or a desktop ETS system.
The following links also touch on the subject as well.
http://forums.ni.com/ni/board/message?board.id=170&message.id=147602&requireLogin=False
http://forums.ni.com/ni/board/message?board.id=170&message.id=149424&requireLogin=False
http://forums.ni.com/ni/board/message?board.id=180&message.id=27461&requireLogin=False
I double checked and currently there are no keyboard or mouse VIs that work on real-time targets. You may be able to get around this by finding a serial keyboard and mouse and using VISA calls. Hope that helps clarify, and have a good day.
Brian K.

Using dll in labview realtime

Similar Messages

Maybe you are looking for