Array output of a Labview dll

Hi all,
I haven´t found the solution in the posts of this forum, if somebody has, please inform me.
I want to output an array from a dll compiled in LV7.1. It doesn´t work. I have tried all the combinations of Array Data Pointer & Array Handle Pointer, and the two calling conventions, and it doesn´t work. My output array (Y) is always the unchanged input array. Any idea?

Whithout having your DLL it's difficult to say why your code is not working. There are different ways to pass array data, please also have a look at the examples that are contained in LabVIEW.
You can also find a pretty good tutorial here

Similar Messages

LabVIEW DLL 2D Array output deallocation

Hey everyone,
I am using a custom built DLL made with LabVIEW. One of the functions outputs a 2D array of data by "handle". I can catch the 2D array from the function just fine from within my C program, however I have a question about deallocating the memory allocated by the LabVIEW DLL for the 2D array.
I call the DLL function repeatedly in a loop and as this occurs the RAM used on my machine continues to increase until it is full or I exit the program. There are no other dynamically allocated peices of data within the C program that could be causing this.
The question is, can I call free() on the 2D array handle safely? Is this the correct way to deallocate the 2D arrays passed out of LabVIEW DLL functions? One dimension of the 2D array is always the same size, but the other dimension varies per call.
Here is an example (I have renamed function calls and library headers due to security reasons):
#include "DLLHeader.h"
int main(void)
    ResponseArrayHdl myArray = NULL;
    DLL_FUNC_InitializeLibrary();
    DLL_FUNC_ConfigurePortWithDefaults("COM3");
    DLL_FUNC_StartAutoSend(9999999);
    while(DLL_FUNC_IsTransmitting())
        DLL_FUNC_GetAllAvailableResponseMessagesByHndl(&myArray);      // gets the 2D array
        // do something with array data here!
        free(myArray);   // is this the appropriate way to clean up the array?
        Delay(0.05);
    DLL_FUNC_GetAllAvailableResponseMessagesByHndl(&myArray);      // gets the 2D array
    // do something with array data here!
    free(myArray);   // is this the appropriate way to clean up the array?
    DLL_FUNC_ShutdownLibrary();
    return 0;
from DLLHeader.h:
typedef struct {
    } ResponseMessage;      // created by the LabVIEW DLL build process
typedef struct {
    long dimSize;
    ResponseMessage Responses[1];
    } ResponseArray;
typedef ResponseArray **ResponseArrayHdl;   // created by the LabVIEW DLL build process
I want to make sure this is an appropriate technique to deallocate that memory, and if not, what is the appropriate way? I am using LabVIEW 7.1 if that matters. The C program is just ANSI C and can be compiled with any ANSI C compliant compiler.
Thanks!
~ Jeramy
CLA, CCVID, Certified Instructor

Tunde A wrote:
A relevant function that will be applicable in this case (to free the memory) is the "AZDisposeHandle or DSDisposeHandle". For more information on this function and other memory management functions, checkout the " Using External Code in LabVIEW" reference manual, chapter 6 (Function Description), Memory Management Functions.
Tunde
One specific extra info. All variable sized LabVIEW data that can be accessed by the diagram or are passed as native DLL function parameters use always DS handles, except the paths which are stored as AZ handles (But for paths you should use the specific FDisposePath function instead).
So in your case you would call DSDisposeHandle on the handle returned by the DLL. But if the array itself is of variable sized contents (strings, arrays, paths) you will have to first go through the entire array and dispose its internal handles before disposing the main array too.
Rolf Kalbermatter
Message Edited by rolfk on 01-10-2007 10:43 PM
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

Calling LabVIEW DLL from C with 2d array strings

I am trying to write a DLL in C that calls a LabVIEW DLL that has a
number of functions that each return a 2D array of strings which are the formatted
measurements, with column 1 being the measurement name and column 2
being the measurement. I wanted to use the 2D array of strings since
this would give a uniform interface for returning measurements. Ive
cobbled together bits and pieces of messages and example code I've
found here into something that almost works, and was hoping someone
with a little more experience in interfacing C with LabVIEW DLLs would
be able to help me.
Here's a little
snippet from the header file generated when building the LabVIEW DLL:
typedef struct {
long dimSizes[2];
LStrHandle String[1];
} TD1;
typedef TD1 **TD1Hdl;
long __cdecl TestVI(char serialNumber[], TD1Hdl *formattedMeasurements, char ErrorDescription[], long len);
The "TestVI" VI generates a 2D array of strings. The cell contents and number of rows are random to
simulate different measurement names and measurements.
Here's a snippet for the wrapper class:
class CArgoTestsLabVIEW
public:
CArgoTestsLabVIEW();
virtual ~CArgoTestsLabVIEW();
// test modules called from parent DLL
BOOL GetResult_LV(CString resultName, double *result);
long TestVI_LV(CString serialNumber);
private:
TD1Hdl m_LVStringArray;
CMapStringToString m_resultMap;
InitMeasurementsArray();
PopulateResultMap();
The "m_LVStringArray" is intended to hold the 2D array of strings that
the test modules spit out. The "m_resultMap" is just for accessing the
measurements from the parent DLL via the "GetResult_LV" function.
The implementation of TestVI_LV is:
long CArgoTestsLabVIEW::TestVI_LV(CString serialNumber)
long rc = 0;
char errStr[BUFFERLEN];
strcpy(errStr,"");
rc = InitMeasurementsArray();
if (rc == 0) {
rc = TestVI(serialNumber.GetBuffer(serialNumber.GetLength()), &m_LVStringArray, errStr, BUFFERLEN);
PopulateResultMap();
return rc;
The accessor functions InitMeasurementsArray and PopulateResultMap are:
long CArgoTestsLabVIEW::InitMeasurementsArray()
MgErr err;
if (m_LVStringArray)
DSDisposeHandle(m_LVStringArray);
m_LVStringArray = (TD1Hdl)DSNewHandle(sizeof(TD1));
// code to check for NULL
// Set number of strings in array to 0
(*m_LVStringArray)->dimSizes[0] = 0;
(*m_LVStringArray)->dimSizes[1] = 0;
// Set total size of array structure. For now it is only as big as the long variable.
err = DSSetHandleSize((UHandle)m_LVStringArray, sizeof(long));
// code to check for error
return 0;
void CArgoTestsLabVIEW::PopulateResultMap()
int numberOfResults;
int i;
int charCnt;
numberOfResults = (*m_LVStringArray)->dimSizes[0];
if (numberOfResults == 0) {
return;
m_resultMap.RemoveAll();
for (i = 0; i < numberOfResults; i++) {
charCnt = (*((*m_LVStringArray)->String[i * 2]))->cnt;
(*((*m_LVStringArray)->String[i * 2]))->str[charCnt] = '\0';
charCnt = (*((*m_LVStringArray)->String[i * 2 + 1]))->cnt;
(*((*m_LVStringArray)->String[i * 2 + 1]))->str[charCnt] = '\0';
m_resultMap.SetAt((LPCTSTR) (*((*m_LVStringArray)->String[i * 2]))->str, (LPCTSTR) (*((*m_LVStringArray)->String[i * 2 + 1]))->str);
The problem I have is that I eventually get an access violation from
the run-time engine if I try to call the test VI in a loop. I'm
obviously having a memory management problem, but it escapes me as to
where the problem is. Anybody have any ideas?

smercurio_fc wrote:
The problem I have is that I eventually get an access violation from the run-time engine if I try to call the test VI in a loop. I'm obviously having a memory management problem, but it escapes me as to where the problem is. Anybody have any ideas?
(*((*m_LVStringArray)->String[i * 2]))->str[charCnt] = '\0';
Hi smercurio,
Have you solved this? I don't work with C much anymore, but it looks, here, as if the memory at str[charCnt] isn't yours to address/change.
Is index "charCnt" one char past the end of the String-memory allocated by LabVIEW?
just an idea!
Hmmm, maybe page 9 is a bit far back to fish in the unanswered posts.
Message Edited by Dynamik on 03-03-2006 02:03 AM
When they give imbeciles handicap-parking, I won't have so far to walk!

Passing Array of Srings between Visual Basic and Labview dll

I have searched and searched for the correct way to pass an array of
strings between Visual Basic 6.0 and a Labview 7 dll. So far, I still
do not know how to pass the array. When I create the dll in LV, the
array of strings is presented as a string, not an array. I am familiar
with passing arrays of type double, but I really need to know how to
pass an array of strings. Any and all help is appreciated.
Bob

Hey Bob,
From what I understand, that can get kind of messy. You have to allocate the memory in VB in the format that LabVIEW expects (see the externalcode.h file in National Instruments\LabVIEW 7.0\cintools for details). Then pass a pointer to that location to LabVIEW. There are a couple of related examples online. They don't necessarily show how to pass an array of strings to VB, but they should show how to pass a string and an array. I hope this helps.
Using Microsoft Visual Basic to Call LabVIEW DLLs That Pass String Data Types
http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B123AE0CB9B0111EE034080020E74861&p_...
Using Microsoft Visual Basic to Call LabVIEW DLLs That Pass Array Data Pointers
http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3D9E556A4E034080020E74861&p_...
Regards,
Chris J

How to call labview DLL from C#, passing char, char[], float[], long, short

Hi,
I'm having trouble calling labview dll from C# to perform certain function.
The function supposed to return the values in the float Analysis[] array. However, when I execute it it only returns zero values.
It seems that some parameters are not properly passed to the dll.
Below is the function in the header file:
void __stdcall Optical_Center(char FileDirectory[], long ImagePtr,
    short int Height, short int Width, char ReadFromFile, float Analysis[],
    long lenAnalysis);
and my corresponding dll import in c#:
[DllImport(@"SMIA.dll", CharSet = CharSet.Ansi)]
        public static extern void Optical_Center([MarshalAs(UnmanagedType.LPStr)]string FileDirectory, long ImagePtr,
            short Height, short Width,char ReadFromFile, IntPtr Analysis,
            long lenAnalysis);
string str = @"C:\SMIA.raw";
int len = 3;
long m_lenAnalysis = 3;
long m_ImagePtr = 0;
short m_Height = 2464;
short m_Width = 3280;
IntPtr m_PtrArray = Marshal.AllocHGlobal(len * Marshal.SizeOf(typeof(float)));
char m_ReadFromFile = '1';
Optical_Center(str,m_ImagePtr,m_Height,m_Width,m_ReadFromFile,m_PtrArray,m_lenAnalysis);
float[] m_Analysis = new float[len];
Marshal.Copy(m_PtrArray, floatArray,0,len);
Marshal.FreeHGlobal(m_PtrArray);
string printstr = "";
for (int i=0; i<len; i++)
    printstr = printstr + floatArray[i].ToString() + "\n";
MessageBox.Show(printstr);
Appreciate if anyone can help, thanks.
KL

I was just about to post the header file of the DLL, when
I noticed that there's a function called LVDLLStatus.
This little thingie turned out to be a rather handy tool.
With that function I found that in the DLL I had a problem
with another function that prevented the DLL to be correctly
loaded.
This other function in the DLL is for generating digital output
and it worked as it should, when tested from LV.
Anyway if someone is interested, I got it working by using
the LoadLibrary and GetProcAddress function, as in the
source code thatI posted earlier.
I will investigate what is wrong with that digital output, and
post into a another thread if I have problems with that.

Configure string parameter for LabView dll

Hi,
I have created a simple LV 2010 vi (Starting vi) that reads the identification of an oscilloscope. I then take this vi and build it to a LabView dll. I test the dll by calling it from LabView (RunFrom dll). It essentially seems to work but len and ReadBuffer come back blank. It has to be in the way I am configuring the parameter setup for Readbuffer (Parameter Setup) in the dll configuration. I have tried several different configurations but nothing seems to work. Any help is appreciated!
Jim Haas
Solved!
Go to Solution.
Attachments:
Starting vi.png ‏43 KB
RunFrom dll.png ‏29 KB
Parameter Setup.png ‏20 KB

What's the len parameter for? Normally you would set that as the length of the string, but it appears you haven't done that. Also, you're passing len by value, not by reference, so the function expects it to be an input and you'll never get back a value other than whatever value you provide.
Don't use a local variable of ReadBuffer for the "readbuffer" input. You need to pass an initialized string long enough to hold the expected amount of data. The easiest way to do this is to use Initialize Array to create an array of U8, then use byte array to string. Set the "minimum size" parameter to "len" and pass in the length of the initialized string (this isn't required but is good practice). If you need the resulting length output, add another indicator and parameter for that value. There might be a way to do it with a single parameter by passing len by reference, you'd have to experiment (it's definitely doable in C but I don't know if LabVIEW allows it).

How a variable in C++ gets updated from calling a labview dll running in a loop?

Hi,
I have created a dll which is called from a C++ program. The dll has been created from a vi which continuously runs in a loop (this is necessary because I need to control some hardware in real-time). When I call the function from C++ I can see the front panel of the vi working properly, i.e. all variables are updated in real time on the labview panel (which I will set as not visible once i get this problem sorted out).
However, I can't get the variables' values getting updated in my C++ program and I need these values to change in which way the hardware should behave ... is there any example somewhere in which something similar has been done? I have seen some examples where a dll is called from C++ with a vi function but not running in a loop. In these examples, the vi function passes the datum to the C++ software once is finished ...
thanks very much for your help,
kind regards
Sergio

Hi smercurio_fc!
Thanks very much for your answer!
I have already an inter-process communication, where there are two threads running in parallel. In one thread the C++ code is running while in the other the LabVIEW code is running. The labview function is passing the "output" variables as pointers too.
_1DScan(ReqForce,&StopAlign,0,&ReadForce,&Piezo_running,&RS232OK,&Running);
the function is called using the following:
void CFMControl::FMThreadProc()
_1DScan(ReqForce,&StopAlign,0,&ReadForce,&Piezo_running,&RS232OK,&Running);
return;
When I run the C++ code I can see both threads working by seeing data being updated in C++ front panel (data that belongs to C++) and in labview fron panel (data that belongs to labview). However, when I try to use any of the outputs coming from labview I can't get them updated....

How to pass Visa Resoure Name parameter to labview dll in labwindows/cvi

Hi, everyone
I build a dll from labview, the prototype is : double getchannelpower(double f, uintptr_t *VISAResourceName);
I don't know how to pass VISAResourceName to this function.How can I get the VISAResourceName of this type(uintptr_t *)?
Is it related to the paremeter ViPSession in function viOpen(ViSession sesn,ViRsrc rn,ViAccessMode am,ViUInt32 ti,ViPSession vi)?
BRs,
lotusky

1. uintptr_t *VISAResourceName in the labview dll is connected to viOpen function as input parameter internally.
2.I can call the labview dll in labview via CLF Node, when the VISAResourceName parameter is set to Numeric(32-bit int or 32-bit usigned int) OR Adapt to data(Handle by Value). And I got the value of the VISAResourceName parameter, which is 0; When I directly connect 0 to the dll, it still works. But in labwindows, when I pass 0 to the VISAResourceName parameter of the dll function, I got a FATAL RUN-TIME ERROR: The program has caused a 'General Protection' fault.
mkossmann 已写：
Could you check what exactly uintptr_t *VISAResourceName in your labview dll does.Might it be that it is connected to the labviews Dll internal ViOpen() ViSession output parameter ?. And the name VISAResourceName is misleading.
Another idea would be that Labview uses 32bit Unicode for the ResourceName. And you have to convert the C String to that Unicode first.

Resizing an array of struct inside a DLL using the memory manager

Hi all,
I dug deep inside the boards, but wasn't able to find a solution for my problem.
I'm building a dll, which does some imageprocessing and should return an array of structs to labview, with one struct for every element in the image.
As I don't know the number of elements beforehand and the limit of the number is numbers of magnitude larger then the expected one, I don't want to allocate such a huge chunk of memory prior to the dll call in labview.
In a former version I used a 2d array for the elements, where each row holds the values of every element. Here I used the NumericArrayResize-function, which worked quite well. But I have to add more sub-processes and using structs (or clusters in labview) appears to be more usefull and cleaner for me, in addition I had to cast some of the elements back and foreward a few times.
So one element-struct should hold 2 singles and 1 uint32. My question is now, how can I resize this array of struct with memory manager functions as the NumericArrayResize-functions does not suit this purpose?
(Accessing a given array of structs inside the DLL and after that reading the changed values in Labview is surprisingly easy )
Thanks in advance
Solved!
Go to Solution.

Well, I was able to solve it myself. I found this thread, where the first post of rolfk made me thinking. It appeared to me, that the numericarrayresize-function behaves very similar to the realloc-function of c. So I used the type unsigned int 8 (which is just one byte) and multiplied it by the number of bytes used by one struct, in my case 12 bytes (4+4+4) and then multiplied it by the number of structs (elements in the image) i have. Luckily it worked and the memory block was resized exactly as I wanted it to be. Important to note: do not forget to adjust the size element of the handle, otherwise Labview does not know about the changed size.

Array output from formula node with input variable as array size

Hi,
I have created a formula node with an array output called al, but I get an error "you have connected a scalar type to an array with that type".
I declare the output as follows..
float64 al[len_as];
where len_as is an scalar input to the formula node.
It only works when I put a number as.
float64 al[5];
,but I don't know beforehand how many elements I need, so I cannot use this.
Please help! This is so stupid.
Thanks

Don't define your array in your formula node.
Initialize the array as the size you want and pass it in as an input into the formula node.
Are you sure you even need to use a formula node? Can you implement your formula using all native LabVIEW functions?
Message Edited by Ravens Fan on 10-07-2009 11:51 PM
Attachments:
Example_VI_BD.png ‏3 KB

Array output from formula node

How to get an array output from the formula node.I am trying to use a for loop inside the formula node and want an array output.

You cannot place a For or While Loop inside the formula node.
Here is what the Help Description says about the syntax inside the Formula Node:
Formula Node
Evaluates mathematical formulas and expressions similar to C on the block diagram. The following built-in functions are allowed in formulas: abs, acos, acosh, asin, asinh, atan, atan2, atanh, ceil, cos, cosh, cot, csc, exp, expm1, floor, getexp, getman, int, intrz, ln, lnp1, log, log2, max, min, mod, pow, rand, rem, sec, sign, sin, sinc, sinh, sizeOfDim, sqrt, tan, tanh. There are some differences between the parser in the Mathematics VIs and the Formula Node.
Place on the block diagram
Find on the Functions palette
Refer to Creating Formula Nodes and Formula Node Syntax for more information about the Formula Node and the Formula Node syntax.
Note The Formula Node accepts only the period (.) as a decimal separator. The node does not recognize localized decimal separators.
<SCRIPT type=text/javascript>if (typeof(writeVarRefs)=="function"){writeVarRefs("763");}</SCRIPT>
<SCRIPT type=text/javascript> if(typeof(lvrthelp763) != "undefined"){document.writeln(lvrthelp763)}</SCRIPT>
<SCRIPT type=text/javascript> if(typeof(lvfpga763) != "undefined"){document.writeln(lvfpga763)}</SCRIPT>
<SCRIPT type=text/javascript> if(typeof(lvemb763) != "undefined"){document.writeln(lvemb763)}</SCRIPT>
<SCRIPT type=text/javascript> if(typeof(lvpdahelp763) != "undefined"){document.writeln(lvpdahelp763)}</SCRIPT>
<SCRIPT type=text/javascript> if(typeof(lvtpchelp763) != "undefined"){document.writeln(lvtpchelp763)}</SCRIPT>
<SCRIPT type=text/javascript> if(typeof(lvblackfin763) != "undefined"){document.writeln(lvblackfin763)}</SCRIPT>
<SCRIPT type=text/javascript> if(typeof(lvdsp763) != "undefined"){document.writeln(lvdsp763)}</SCRIPT>
Example
Refer to the Create Function with Formula Node VI in the labview\examples\general\structs.llb for an example of using the Formula Node.

Access labview dll in labwindows

Hello,
Q1. I have created a DLL in labview8.2. I have included the header file and the library file in my LabWindows project. When I compile the code it throws up an error in header file extcode.h. I have attached the error messages with this post in a file. Can anyone please guide me fixing this error. Also related links to creation of DLLs in Labview and accesing these DLLs in CVI would also be helpful.
Q2. I have created a VI which has input parameter as a cluster. The cluster has integer data type and an array of integers. I am creating a DLL out of this VI. Are there any limitations for accessing the cluster from CVI? How do I resolve them?
Thanks in Advance,
Pradeep
Attachments:
extcode_error.txt ‏2 KB

Hello Pradeep,
The compile errors you posted seem to indicate that the header file was incorrectly generated or modified. I would suggest going over it the header file for any syntax errors in the region where the first error is thrown. You could also try to regenerate the header file by recreating the dll. I have found two links that should help you get started with using a LabVIEW dll in CVI and also using clusters with dlls. I would recommend, however, that you continue to search through the forums and Developer Zone. There is a wealth of information here that is very helpful.
KnowledgeBase 3337DOV4: Calling a LabVIEW DLL from a CVI or other C/C++ project
NI Developer Zone Example: Using Structures in a DLL with Clusters in LabVIEW
Adam
National Instruments
Applications Engineer

How to call Labview DLL from VB2005

Dear all expert,
I'm a student and very new in Labview programming.
Currently i have build a simple vi and need to convert it to dll so that i can call it from my VB.net. But the problem is how to call the labview dll from my VB.net?
I know we must declare function something like this,
Auto function Bodeplot Lib"..\\Bodeplot.dll" (Byval Val1 as double, Byval Val2 as double,...) as double
but how to determine Val1, Val2 (and so on) is input for which data? if my vi have 10 input (frequency, Kc,Fcz,Fcp,Wzrhp,Wp,k,Wz,Beta and Operation) ? and how to select the output (my application have 3 possible output : magnitup loop,phase loop, and degree loop)
In addition, since I'm using Labview 8.0 , and as i know apllication builder for this version cannot convert vi to dll which contain Mathscript (but unfortunely, my vi all use Mathscript), so really hope someone can help me to convert my vi to dll using Labview 8.2 (which remove this limitation).
here I'm attach my Vi and really hope someone willing to help.
Thank you.
Attachments:
bodeplot.vi ‏1049 KB

On Sep 17, 6:40 am, cckoh <[email protected]> wrote:
> Dear all expert,
> I'm a student and very new in Labview programming.
> Currently i have build a simple vi and need to convert it to dll so that i can call it from my VB.net. But the problem is how to call the labview dll from my VB.net?
>  
> I know we must declare function something like this,
>  
> Auto function Bodeplot Lib"..\\Bodeplot.dll" (Byval Val1 as double, Byval Val2 as double,...) as double
>  
> but how to determine Val1, Val2 (and so on) is input for which data?  if my vi have 10 input (frequency, Kc,Fcz,Fcp,Wzrhp,Wp,k,Wz,Beta and Operation) ? and how to select the output (my application have 3 possible output : magnitup loop,phase loop, and degree loop)
>  
> In addition, since I'm using Labview 8.0 , and as i know apllication  builder for this version cannot convert vi to dll which contain Mathscript (but unfortunely, my vi all use Mathscript), so really hope someone can help me to convert my vi to dll using Labview 8.2 (which remove this limitation).
>  
> here I'm attach my Vi and really hope someone willing to help.
>  
> Thank you.
>  
>
> bodeplot.vi:http://forums.ni.com/attachments/ni/170/272124/1/bodeplot.vi
If you insist on using Labview with your project then you should
consider using ActveX in place of using a dynamic link library to
interface to your VB.net code. You don't need "Application Builder"
if you use ActiveX. The Student, Basic and Full development versions
of Labview for Windows come with ActiveX capability. For more
information on ActiveX look up the subject ActiveX in Labview's Help
File.
Howard

Exchanging 2 D array between VBA and labview

I have a project : half part is VBA writen, half part is Labview coded. Both parts are writen to operate manually. The first one prepares data and charts them on charts sheets, the second one smooths data with ready made labview curves fitting VIs. So I want operator could use them seamless, that means calling labview from VBA 2007 code collecting X,Y data into a 2 D array, then send it to labview DLL smooth the curves and send back an array with smoothed data to excel through VBA.
My concern is how to declare 2D array parameters in VBA and in Labview in order to work fine (array of variants or doubles, parameters declared by ref or by val)
I have seen similar topics in NI forum but they dealt with VB.net and not VBA .
I run office 2007 and labview 2009 full dev. system with application builder.
Regards

bassevellois wrote:
Thank you for the answers.
The examples provided with labview for ActiveX exchanges are not very clear. I want to use labview as ActiveX server and Excel through VBA as client.
There's only one example that I know of that ships with LabVIEW and it shows how to access LabVIEW from VB using LabVIEW's ActiveX server. It opens a VI and runs it. Doing it from VBA is very similar. You want to add the reference to the ActiveX Server in your VBA project. If you're controlling the LabVIEW development environment directly, then the library to include in your list of references will be "LabVIEW x.x Type Library". If you are controlling a LabVIEW-build app, then the library name will be whatever you specified when you built the app.
I have no idea of creating and exposing classes, methods or properties needed in VBA from my Labview VI which was at the beginning a standalone application.
I don't quite understand what you are referring to. The ActiveX Server in LabVIEW and a LabVIEW-built app are pre-defined. You do not export anything from your LabVIEW VI. The available properties and methods are a function of the LabVIEW ActiveX Server, not of your VI. If you are building an app then you just need to enable the ActiveX server for the application, and that's done in the build specification.
How to reproduce my example:
Make sure you've enabled the ActiveX Server in LabVIEW.
Download the attached 2D_VBA_Test VI to your C:\Temp folder. You can save it anywhere, but you'd have to change the path in the Excel VBA macro.
Download the attached Excel workbook.
Open the workbook and click the button. If LabVIEW is not running it should launch LabVIEW, and open the VI and populate the front panel array with the values from the spreadsheet.
Attachments:
2D_VBA_Test.vi ‏6 KB
VBA to Excel.xls ‏24 KB

Error while caling Labview DLL from VB2005

Dear all expert,
i'm a student and very new in Labview. Currently, i design a application using Labview8.2 and need convert it to dll. So that i can call it fom my VB2005.
I'm encounter an error, there is my computer "hang" when calling the labview dll. I suspect this may due unproper way i calling the labview dll in my VB program. So, really hope some one can give me any suggestion and modification to my program. I attach my vi and Vb program.
for your information,
i already install labview run time engine 8.2.1 and uncheck the "Loader Lock detected".
below is the Function Prototype create when i using Application Builder to build the dll.
void Bodeplot(unsigned short Operation, double Beta, double Frequency, double Kc, double Fcz, double Fcp, double Wz, double Wp, double Wzrhp, double k, double *Output)
Thank you very much.
Attachments:
MyProgram.zip ‏723 KB

Hi cckoh,
A couple suggestions include:
1) Make sure you are using the correct .NET data types that map to the data type that LabVIEW uses. For example, your Operation paramter for your DLL is an unsigned short which is equivalent to a System.UInt16 in .NET.
2) You should be using ByRef instead of ByVal for your output parameters. For example, in your function prototye, you have double *Output. For example, when you import your unamanged DLL, the prototype you should use woudl be:
Declare Auto Function Bodeplot Lib "........."(ByVal Operation as System.UInt16, ........ ByRef Output as Double)
I tested this out and it loads the DLL, calls the function, and returns without problems.
Hope this helps!!
Best Regards,
Jonathan N.
National Instruments

Array output of a Labview dll

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