Call lvlib in LabVIEW

Similar Questions

• Calling DLLS in LabVIEW

  Hello

  Below is the code written in LabWindows in which dynamically access a Dll using Windows API LoadLibrary(), GetProcAddress(), and FreeLibrary().

  Successfully, I could load the library and get the procedure address using library calls node in LabVIEW. But got stuck after that.

  As I am not good in C/C++ coding, ask someone to really help me to write the same thing in LabVIEW.

  Kindly do the needful.

  #include   // Function prototypes.
  #include     // CVI Active X definitions.
  #include 
  #include    /* Needed if linking in external compiler; harmless otherwise */
  #include 
  #include 
  
  typedef long __stdcall( *OLECREATEOBJECT)(char*);
  static  HINSTANCE  Hinstlib;
  static  long  gvntISystem;
  
  long CviCreateFastObjects (void)
   {
  OLECREATEOBJECT procAdd;
      pStrTempmem      = (char*)CA_AllocMemory(1);
      Hinstlib = LoadLibrary("FastTrio");
      if( Hinstlib != NULL)
  {
          procAdd = (OLECREATEOBJECT) GetProcAddress(Hinstlib, "OLECreateObject");
          if(fRunTimeLinkSucess = (procAdd != NULL))
  {
          gvntISystem = (procAdd)("FAST.IMFASTSystemInterface");
          return 0;
          }
          else
          return 1;
          }
      else
          {
  return 1;
          }
  }
  

  All the information you need are in the C code.

  • OLECREATEOBJECT is typedefed just after all the #includes at the top.  It returns a long integer (typically I32 in LabVIEW, but could be I64 on a 64-bit operating system) and takes a string as input.  It uses the standard windows calling conventions, not the C calling convention.
  • LoadLibrary and GetProcAddress are used to get a pointer to the function (procAdd).  This is handled in LabVIEW, by filling in the location of the library and the function in the call library node.
  • The library of appeal in LabVIEW node must also be set to the standard calling convention and return value (I32) and list of parameters (a string) must be set.
  • the function is used to set gvntISystem with a constant of entry 'FAST. IMFASTSystemInterface ".  In LabVIEW, a constant string of wire at the entrance and read the return value.
  • You can implement the audit, thus using the call library errors node error output.

  Good luck!

• Efficiency call DLLS in Labview

  Hello

  I'm working on a labview program for the treatment of the data in real time.  Thus, code running efficiency will be critical.  I wonder how about the cost of calling DLLs.  Similarly, what the call cost of the subprogrammes.

  To implement the same function, the call of a Subvi will be faster than calling a DLL?

  If I can develop all screws Sub in the main program and delete all the calls, which will be much faster?

  Can someone give me any clue or guideline?

  Thank you.

  CRXX wrote: [...]

  I'm working on a labview program for the treatment of the data in real time. [...]

  What is the OS you are using?

  Since you ask in general, I answer in general:

  This question cannot be ansered. This is a case-by-case-thing and must be assessed individually.

  Most of the effect will be the memory management: which allocates the amount of memory? When it's done?

  Memory of ESP. allocation mess up determinism, if a DLL can perform worse than pure code LV (given a BONE of RT LV). But it might be preferable for some algorithms encapsulated... no one can say in general.

  Perhaps the most important question is:

  How many times is that the code (DLL vs Sub - VI) called and how short is its runtime? If the load of execution: calling code relationship is very low (-online 1:1), it is best to "solve" the subcode. SubVI Inling is a valid way in pure BT (from 2010).

  If the code is called rarely, this whole discussion is somehow obsolete as the overload of calls will be negligible, even if it would be quite high...

  And no, C is not faster as LV by definition. It also depends on the task and how you implement it...

  hope this helps,

  Norbert

• Error 1097 when calling DLLS in LabView

  I get an error 1097 when calling the LabVIEW provider library. Curiously, the error, the DLL routines still seem to do what is asked of them.  This is the test code.  It opens an Ethernet connection to a controller of axes Galil, he asks (possibly) the value of its internal clock, and then closes the connection.  Each call library function returns error 1097 but "valve function" I32 error number is always zero. Open function causes the connection to be opened, the command function causes the send command and receives a reasonable answer, narrow funtion seems to cause the connection to be closed.

  

  Here is what I see when I run the test:

  

  Also directly configure call-library functions, as I did in this VI, I also tried using the import-shared-library Wizard to create a vilib of functions of the DLL and I get the same behavior and errors when I use these functions.  I tried to tweak some of the data types in my configured manually call library functions to see if I could find a combination that worked better with the library, but had no luck there.

  I use the x 86 version of the DLL with v2014 LabVIEW 32-bit on a 64 bit windows system 7.  I see that the error on the two computer systems of different work configured in this way. I see a similar error on a home computer with just the RTE of 2014 installed. The manufacturer says they can not reproduce the error. I always saw the error over multiple versions of their library DLL.

  In the attachment ZIP it has a link to the DLL library on the manufacturer's website. There is also a copy of the VI, the DLL and a large part of how-to-use documentation that accompanies the DLL.

  I was hoping that someone who was familiar with the use of the call-library function might take a peek at what I do and see if an error could be spotted.

  Unable to find an error, I did, I would be happy to suggestions on how I could solve this. Little seems to me like there may be a problem with the library. The manufacturer, Galil, said that they have opened a log with OR to see if NEITHER could help but since Galil said they can not reproduce the problem and provide an example of the NC, it really went anywhere.

  Given the decoration of symbol names as exported by the DLL I "m convinced that you must change the stdcall calling convention.

• Python, call DLLs in LabVIEW: Fatal internal error when accessing output String Cluster

  Hello

  We have compiled a DLL in LabVIEW (TestError.dll) and tried to call it from Python.

  TestError.dll includes 2 functions:

  1 testErreur: cluster 1 entry string, 1 channel indicator

  2 TestError2: 1 channel input, 1 bunch of output string

  What we try to do in Python is actually something like this:

  1 provide values to controls in the functions of the DLL.

  2. call the DLL.

  3 get the values of the indicators.

  What we have seen are:

  1 read/write operations on normal data types (string, digital) indicators/controls are OK

  2. write operation on the Cluster string entry is OK

  3. read operation on the Cluster output string is not OK. The following error is still prompted for:

  «Unrecoverable internal error: 'MemoryManager.cpp', line 437.» LabVIEW version 8.6... »

  Also joined the TestError.prj and python code.

  Grateful if someone can help to explain why we get this error and how to overcome?

  Thank you

  howmean

  What we have seen are:

  1 read/write operations on normal data types (string, digital) indicators/controls are OK

  2. write operation on the Cluster string entry is OK

  3. read operation on the Cluster output string is not OK. The following error is still prompted for:

  «Unrecoverable internal error: 'MemoryManager.cpp', line 437.» LabVIEW version 8.6... »

  Also joined the TestError.prj and python code.

  It is very logical that it does not, and the bad news is, it cannot really be implemented reliable of a process not LabVIEW.

  LabVIEW channels (and tables) are very specific species. They are then called handles, which are pointers to a pointer to a block of memory. If you have a control or indicator on its own, the Prototype configuration allows you to configure this setting as a C. LabVIEW data pointer, when creating the DLL, create heels C for each exported function and place the code to do the translation between the past C pointer to and necessary LabVIEW data handle. For strings and arrays within the cluster, there is no configuration option and the DLL is expected to pass a structure with data handles native LabVIEW in there.

  You may say that creating handles data in your calling process enough to trick LabVIEW. For the input variables that actually CAN sometimes work (but is a delicate and dangerous generally to handle this). There is no way to make it work for output variables. LabVIEW will try to resize handle to fill data in that he wants to make. This resizing is done using internal memory manager of LabVIEW. This will work only if it had been allocated by EXACTLY the same instance of the memory manager. Otherwise, it refers to a different memory segment and catastophally fail. The only way to make this work perhaps, with luck, taking your heart and prayer to the gods, is to lvrt.dll to allocate a handle that you must pass to the DLL. Still find the good lvrt.dll, which will execute your DLL LabVIEW is a major challenge.

• How to call sequence into LabVIEW, by providing the path of the sequence files.

  Hello

  Please give me a solution for call sequence from the API ActiveX LabVIEW file by entering the path of the LabVIEW user interface sequence.

  Thank you

  Wherry

  Here is a link I gave some pointers on how to run a file opened via Single Pass sequence.

  http://forums.NI.com/T5/NI-TestStand/direct-execution-of-the-sequence-when-UI-launches/m-p/2000819#M...

  How are you going to start this sequence is the user who selects the sequence on the disk?    Is already open in a SequenceViewMgr control?

  An operator interface would be more applicable to your situation?

  Thank you

  PH

• What is the right way to specify the location of the shared library in an a .lvlib function call library function node?

  I'll have a bit of a problem with how to specify the location of library shared in a call library function node it is a VI that is part of a library of LV. Here's a little background which may help.

  I do a lot of measures using spectrometers photo from several manufacturers.  Someone in my company developed a C DLL library, which provides a simple API for all the different spectrometers. To facilitate this DLL to use in LabVIEW, I wrote a .lvlib that wraps all the functions.  When I want to use the API, I simply include the .lvlib file in my project that allows me to drag and drop the wrapper s VI on my block diagram. When I created the .lvlib of VI, I specified the path in the call library node. /. * so it will always look in the local application to the DLL directory when I run.

  The problem is, when I load demand, LabVIEW you asks for the location of the DLL even if it's just there in the local directory! I tried to put copies of the DLL in the directory with the .lvlib, but he still refuses to find the DLL loading.  What I am doing wrong?

  You should in this simple case enter the full path to the DLL by navigating to it. If the DLL is on the same volume/drive that the VI containing the call library node LabVIEW will be internally store the relative path from the VI to the DLL (but still show the absolute path). If you move the DLL and screw together (so the relative location of the DLL to the VI remains the same) LabVIEW will always find the DLL.

  I don't think that the lvlib would add nothing to that.

• TestStand call using LabVIEW VI

  Hello

  How to call teststand through LabVIEW and LabVIEW indicator of day?

  the two should operate in parallel and for this VI I spend only a sequence file path. (except UI example suggest me other examples)

  Best regards

  Usually you have a UI call TestStand.  The user interface can be built in LabVIEW.  Here is the document on the development of the user interface:

  http://www.NI.com/white-paper/7560/en/

  Then you use the Messages of the user interface to communicate back and forth between the user interface and your movie file.

  http://www.NI.com/Tutorial/4532/en/

  Hope this helps,

• How can I prevent labview "Getting Started" page to open when you call a VI in Teststand?

  Hello

  When my file of sequence called a VI, Labview "Getting Started" page opens and will remain open even when running the file sequence ends. I made sure the option "Show VI before Panel when called" is not checked, but still the same issue.

  I appreciate any help on this.

  Thank you

  Ayman

  Try these options here

• Call a C-built DLLS in LabVIEW

  Hello!

  I try to get knowledge on how to call DLLs in Labview.

  I found a very good example on this site:

  http://zone.NI.com/DevZone/CDA/EPD/p/ID/1513

  I downloaded and extracted the call_c_dll_in_lvnew.zipfile.

  When you try to open the sample file GenSortRandC.vi in the folder LabVIEW_code_and_DLL

  I get the following error message.

  "The procedure entry point not found RebootRTSystem in the library cvirte.dll dynamics."

  I searched on the Internet and some forums but so far without success.

  Could you please let me know if you have the same problem the example whith?

  I have the following configuration:

  -Labview 8.5.1 FDS (default installation)

  -Windows XP sp3

  Best regards

  Mattias

  Sweden

  Mattias salvation,

  I have no problem with this example. I can't run without error.

  It's maybe because I installed the CVI Run Time engine.

  Mike

• How to pass a pointer in calling labview library using dll programmed in Labwindows?

  Hello

  I'm trying to interface a camera with Labview.  However, the camera can only be programmed in C, so I use Labwindow CVI.

  I need to pass a handle from the camera of a function to another, for example. leave an opencamera function to function setparameter.

  / * Loading the Qcam driver and open the first camera * /.
  Sub DLLEXPORT LoadDriverAndOpenCamera()
  {
  QCam_CamListItem cameraList [10];
  unsigned long cameraListLength is sizeof (cameraList) /sizeof(cameraList[0]);.

  load the driver
  QCam_LoadDriver();
  a list of cameras
  QCam_ListCameras (cameraList, & cameraListLength);
  listLength is now the number of available cameras

  QCam_Handle CMAH;
  Open the first camera in the list
  QCam_OpenCamera (cameraList [0] .cameraId, &hCam);)
  }

  Apparently, the caemraId is a long unsigned (unsigned 32-bit by 32-bit Labview 2012?) and QCam_Handle is defined as void *, so it is a pointer that points to a non signed 32 bit.

  When I only use C for programming, I can pass variable CMAH to other duties so it is declared as a global variable.  Ex, the following function can be Sub SetParameter(QCam_Handle hCam).  However, here, I trying to do a Labwindows/CVI dll and then call LoadDriverAndOpenCamera() through library function call in Labview.

  My question is: How can I switch CMAH to other functions in the same dll?  I have to add the parameter to the function? For example:

  Sub DLLEXPORT LoadDriverAndOpenCamera(unsigned long cameraId, QCam_Handle* cameraHandle)

  And then add two lines:

  cameraId = cameraList [0] .cameraId;
  cameraHandle = CMAH;

  in the service?  So I spend cameraHandle out?  However, the CMAH will always have kind of vacuum.

  Even if this is the case, how can I configure node call library on Labview?  In the arg parameter set up, I do not see pointers?  It seems that I can not put in place an exit node to be a pointer that points to an unsigned long.

  Thank you very much for your help!

  Best,

  Charles

  Hello Charles,

  I noticed that you posted something similar here. you have questions about the use of the call library function node?

• Acquire GigE camera data using labview CIN or DLL to call.

  I am tring to acquire data from a basler runner line CCD camera (GigE).

  Because the NI Vision Development Module is not free, and the camera provide a C++ API and C and also some examples, so I plan on using the function CIN or call DLLS in labview to achieve. Is this possible?

  I tried to generate a DLL with the example of the company code of the camera. But encounter difficulties;

  I did that a little background in C++, but not familiar with it. The C++ Code example provides the camera is a C++ (a source Code file) and a .cproj file, it depends on other files, the camera API directory.

  If I build the project directly, it will create an application window, not in a DLL. I don't know how to convert a DLL project, given that other information such as dependence in the .cproj file, other than source code.

  Can someone help me with this?

  Don't forget that for the acquisition of a GigE camera, you must only Module of Acquisition of Vision, not the entire Vision Development Module. Acquisition of vision is much lower price and also delivered free with hardware NI Vision current (for example a card PCIe - 8231 GigE Vision of purchase). You need only Vision Development Module if you then want to use pre-made image processing duties. If you are just display, save images to disk, or image processing using your own code (for example to manipulate the pixels of the image in a table) you can do so with just Vision Acquisition.

  It is certainly possible to call DLL functions if LabVIEW by using a node called library, it would be quite a lot of work unless you are very familiar with C/C++. Since their driver interface is C++, you need to create wrapper functions in C in a DLL that you write. Depending on how much you want to expose functions, this could be a bit of work.

  Eric

• allocation of an array of 2d in labVIEW and move to the DLL function to obtain data

  Hi all!

  I searched a lot about this, but one cannot find any solution. Please find attached the vi that I try to get a unit of 32 channels data,

  100000 samples per channel with 14-bit resolution. And please also find enclosed the header for my dll file. (in the header, it is the GetBuffers function).

  There is not a lot of data, it is a little more then 6 MB in the task of LAbVIEW Manager eats about 30 MB more memory, then it should. Are there explanations why?

  Because there is much more data in a single channel (million samples or more)

  Then I will try to allocate a 2D to data array, but when I try to run my LabVIEW vi crashes.

  Could you please help?

  Best regards

  Tomzi

  Dear Tomzi!

  To allocate the data in a table in LabVIEW, you must always initialize, as in a you must have a valid entry on cell (x-, y - 1) have a size of table of (x, y). It is usually best to use the function Array initialized for this purpose.

  There are ways to pass arrays 2D to DLLs, cand find you examples of both in examples > communicate with external Applications > external Code using the > integrating DLLs > DLL.vi call. Basically, LabVIEW can pass in the form of a big table 1 d 2D tables, so you'll need to spend too much table size index it. If you pass the array 2D handles it is preferable to use the typedef that LabVIEW generates for you, something along the lines of

  / * LabVIEW created typedef * /.
  
  typedef struct {}
  
  	Int32 dimSizes [2];
  
  	Double elt [1];
  
  	} TD1;
  
  typedef TD1 * TD1Hdl;

  I hope this helps.

  Best regards:

  Andrew Valko

  NOR Hungary

• LabVIEW MoveBlock and obtaining of a string from a DLL (assigned by the DLL)

  Hello classmates addicted LabVIEW,.

  I have a small question about the LabVIEW MoveBlock function.

  For a project I need to use an external DLL that must be called by my LabVIEW program.

  Essentially, the DLL returns a void * to a buffer and the size of the buffer (size_t). This stamp is just the string being returned by the DLL data. The DLL allocates these data and later in the program that I need to pass this pointer to a second function of the DLL to explicitly inform the DLL that I made using the data, so it can release these data.

  Here is the documentation for the function I want to use:

  Since you say the works of XNode, then you're dealing with a pointer and not a handle (pointer to a pointer), so you should be to pass the address of MoveBlock by value and not as a pointer to a value.

• Loop timed in LabVIEW DLL does not close

  Hello!  I have what I think, it is a simple loop timed in LabVIEW that stops after 100 iterations by throwing an error and letting the loop 'stop on error.  It works fine when it is executed in the ordinary LabVIEW environment, however, when compiled as a Dynamic Linked Library (DLL) and called from LabWindows it requires me to put an end to execution, rather than going out nicely.  As well, it seems to leave the real appeal of virtual Instrument very well and go to the next line of code, but when my function main() in LabWindows is completed it must always be something not cleaned which is the cause not come out well.  Any ideas?   I tried to add only a call to QuitLabVIEW and that doesn't seem to do it.

  Thanks in advance - hoping you will notice an error really easy. )

  A photo of the timed loop is attached.

  An excerpt from the code of LabWindows:

  int main)
  {
  CallMyLabVIEWDLL();  This line launches successfully and closed the window for my virtual instrument LabVIEW
  MessagePopup ("' My Title:", "That occurs after the call to your LabVIEW DLL" ");    This popup appears - indicating the call to the DLL has finished

  But after the code has completed LabWindows always shows "running", rather than close.

  return 0;
  }

  Why do you use a loop timed in the windows environment?  They are best used for real-time environments (not windows) and tend to have more support than the time.

  Is there a particular reason, a while loop will not work?