Calling NIST from Labview

Does anyone have any experience using NIST software with Labview. I am wanting to call NIST to get properties of two different gases, and not exactly sure how to accomplish this.
Can anyone point me in the right direction?

aputman wrote:
I use a TCP connection to get NIST time. Not sure if something like this is available for what you are looking for. Hope it helps.
NISTime-32.exe is shareware and available here
Their is a command line hook so you can just call it with the system exe from LabVIEW
Jeff

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Calling Teststand from labview

Hi,
I am trying to open teststand(3.0) from labview(7.1). When run the VI In highlight mode it works fine and opens the Teststand login panel.When try to run the VI in normal mode the VI Hangs and it doesn't open the Teststand also i have to terminate the application using taskmanger. I have attached the VI and the snap shot in highlight mode for your reference.Any suggestion will be appreciated.
Thanks & regards,
sathyendra N
Attachments:
VIANDSNAP.zip ‏90 KB

Hi,
Thanks for your Response. I am trying to use customize the Opertor Interface developed in labview.
Regarding the complete Application Back ground.
The complete Application was developed previously using labview 6.1 and Teststand 3.1 and it was working fine. Now i am trying to port the application to Labview 7.1 and Teststand 3.1 at that time it is not all opening the Teststand login so i thought tried only the basic part out of my code and that given the inconsistent problem so i am trying to slove that part first so i have made a simple vi which i included in my last mail.I want to maintain the same functionality previously developed in Labview 6.1 without any major changes so i am trying the same way in labview 7.1.can you please suggest some examples or suggestion.Waiting For Your Response.
Regards,
sathyendra N

Calling Dlls from LabVIEW

LabVIEW Gurus:
I am working with some software engineers who have no experience in LabVIEW. Unfortunately I have little experience in C/C++ to make sense of their inquiry.
Basically we are dealing with “Data Marshalling”. I will call a DLL and issue a command (string) and get back a 2-D array and an integer. So far so good.
The C/C++ programmer requested that I provide them with a pointer/memory address in which they will store data, so I can read it once the dll returns the array and integer. I browsed through the example online http://decibel.ni.com/content/docs/DOC-1690 and thought that if I wanted to read from the dll, the process is a simple as calling the appropriate function and configure the parameter (no pointers needed).
So, is there a specific way that they need to write the C/C++ code to be used in LabVIEW? Or what else to I have to take into consideration?
Thank you,
Santiago

That example is pretty simplistic as it only deals with integers. In this case no pointers are required since everything is returned by value. When you're dealing with arrays, however, you need to deal with pointers. If you open the Example Finder (Help -> Find Examples) and search for "dll" you will see the "Call DLL" example. That contains many examples of how to call DLL functions with a wide variety of datatypes. I strongly suggest looking at that example. There is also a chapter in the LabVIEW Help on calling DLLs (Fundamentals -> Calling Code Written in Text-Based Progamming Language).
You have 2 things to consider:
You're dealing with arrays - this means you typically need to pre-allocate the memory in LabVIEW, and it sounds like that's what the DLL expects you to do. This amounts to using the Initialize Array function to create your 2D array of the appropriate size and datatype.
You may be dealing with a C++ DLL. LabVIEW can only interface to C DLLs. This doesn't mean that you can't create a DLL in C++, but it does mean that the C++ programmers need to add an extern "C" modifier to the function calls, otherwise you get name mangling, and LabVIEW won't be able to call the DLL. The DLL programmers should know what that means.

How to call Exe from labview?

Hello NI,
I want to call the exe from the labview. presently i am using command.vi to open the exe. but it works only with source code. after creating the exe it doesnt work.
I checked the path of exe.
do you have any solution for this?
Regards,
Balaji DP

Working directory should be c:\windows\system32
copy your winword.exe into that system32 folder and just try this
Message Edited by mathan on 01-06-2009 03:24 AM
Attachments:
untitled.PNG ‏3 KB

Calling executables from LabView

I would like to know how to call an executable program from within my LabView program.

use the
System Exec.vi
you find it under the menu "Communication"

Calling Matlab from Labview returns a 1047 error - what am I doing wrong

above

Does your script work fine in MATLAB? Do you run a VI or an .exe?
MATLAB must be running, otherwise LabVIEW will be unable to access the MATLAB server. This will cause the 1047 error. Manually start MATLAB, and your program should run without the error.
The following KnowledgeBase may also be useful in troubleshooting this issue
LabVIEW 6.x and Earlier Does Not Interface Properly with MATLAB 6.1 or MATLAB 6.5
Zvezdana S.
National Instruments

Easiest way to call MATLAB from Labview

I have a bunch of MATLAB scripts I've developed over the years. I'd
like to have Labview collect data and pass it off to my MATLAB scripts
for plotting and analysis as it is streaming in. What is the easiest
way for me to do this?
Thanks for your help,
Matthew Little

[email protected] (Matthew Little) wrote in message news:<[email protected]>...
> I have a bunch of MATLAB scripts I've developed over the years. I'd
> like to have Labview collect data and pass it off to my MATLAB scripts
> for plotting and analysis as it is streaming in. What is the easiest
> way for me to do this?
>
> Thanks for your help,
> Matthew Little
Matthew:
Have you tried the Matlab script container in the Mathematics->Formula
function palette? This node allows you to put your scripts into the
Labview diagram. I haven't tried it myself, but it should work. Good
luck.
sm

How to call another program from LabVIEW?

Hi!
Is there anyone that can answer my question? I have found a similar thread where the user needed to call labVIEW from some program but I want to do the opposite.
I made a program in labVIEW that communicates via COM-ports (serial communication) with the processor I use at the job (Ubicom´s IP2022).
Now I want to add more funcionality to this program. I want to be able to program re-program IP2022 through this LabVIEW application.
The programming is done via an Ethernet-dongle. I start a program called IP2kProg, I write the ip-address of the dongle and the program-file (.elf) downloads at this address. But how can I do this from
LabVIEW, do I need to open IP2kProg or can I send some values to it via LabViEW?
Ant suggestions?
Thanks, Amir

Amir,
There are couple of options:
1. If your IP2kProg program has a command-line interface, you can use LabVIEW's System Exec.vi and send the commands and parameters to it.
2. If the IP2kProg has an API / exported functions, you can call them from LabVIEW using the Call Library Function Node.
Hope this gives you some ideas.
-Khalid

How can i call a DLL file from labview?

Iam using a sensoray 2601 module.It is given as DLL file(S2600.DLL).How can i call this function from LabVIEW?
Please Mark the solution as accepted if your problem is solved and donate kudoes

As far as I can tell problems might occur with the call library function node if the the DLL from visual basic is actually an ActiveX dll if that is the case it seems calling the dll by using the Invoke node is the way to go.
Have a look at this
/sletten

Call function in LabView from a DLL, then access global variable from DLL

I have created a DLL in LabWindows with a function and a structure. I want to call the function from within LabView and then access the global structure. I am able to call the function from the DLL with a "Call Library Function Node" and can access the return value, but I cannot figure out how to access the global structure. The structure is declared in the DLL header file with __declspec(dllimport) struct parameters.
Is there any way of accessing this structure without using the Network Variable Library?
Solved!
Go to Solution.

dblok wrote:
When you say "access to" or "the address of" the global variable, do you mean to pass the variable as an argument to the function call in the DLL? If so, then I was not really sure how to pass a cluster from LabView by using the "Call Library Function Node".
Yes, that's exactly right. I would include a pair of helper functions in the DLL to read and write the global variable. Alternatively you might write separate helper functions for each field inside the global structure, depending on the number of fields and whether you want to do any validation on the values.
You can pass a cluster by reference to a function that expects a struct by setting the parameter to Adapt to Type, so long as the cluster does not contain any variable-length elements (strings or arrays). The cluster needs to match the struct exactly, and sometimes that involves adding extra padding bytes to make the alignment work. Variable-length elements in LabVIEW need to be converted to clusters containing the same number of elements as the struct definition (for example, if your struct contains char name[12], you would create a cluster of 8 U8 values, and you could use String to Array of Bytes followed by Array to Cluster to convert a LabVIEW string into that format). If the struct contains pointers it gets more complicated, and it may be easier to write functions in the DLL to access those specific elements individually.
If you can't get this working or need help, post your code and an explanation of the error or problem you're seeing.
EDIT: it is also possible to include a single function in the DLL that returns the address of the global variable, which LabVIEW can then use to access and modify the data, but that's more complicated and likely to lead to crashes if you don't get the memory addressing exactly right.

Creating a DLL in Labview 8.6 and calling it from Visual Basic 6.0

Dear friends,
I need to create a DLL in Labview 8.6 and call it from Visual Basic 6.0. The system works as follows:
I made an application using Labview 8.6 + Vision Assistant 8.6 where I can obtain the x,y coordinates of a template in an certain image being captured by an USB camera. The template coordinates change every time it moves and Visual Basic 6.0 must read these x,y values in real time. I found some information in the link http://zone.ni.com/devzone/cda/tut/p/id/3925, but it works for version 6.x of Labview and 8.6 version is different. Am I in the right path? If you have an updated tutorial like the one in the link above but for Labview 8.6 It would be very nice. Please help me.
Kind regards.
João Júnior

Hello Osvaldo,
I analysed the updated tutorial you sent me, but the thing is that it doen't show how to create the DLL in LV 8.6 but only show how to accessing the DLL from VB6. My problem is really HOW TO CREATE THE DLL IN LV8.6. In the link http://zone.ni.com/devzone/cda/tut/p/id/3063 there is detailed information about how to do this in LV6.x, the problem is that I don't find the path Tools»Build Application or Shared Library (DLL) in LV8.6, I think the procedure in LV8.6 is a little bit different. Don´t you have an updated tutorial on how to build a dll in LV8.6?How could you help me?
Kind regards.
João Júnior

Not found error message from LabVIEW runtime when called from VC++ with statically linked MFC

I have a dll built using LabVIEW 6i. I am calling the dll from a VC++ application. When the application loads I get an error pop-up 'cannot find LabVIEW runtime'. If I change the VC++ code to dynamically load MFC (using the loadlibrary function) or dynamically load the LabVIEW dll I created then the problem goes away. Only when both are loaded statically do I get the error message.
The target machine is running Win2K pro and has the LabVIEW runtime installed.
I do not want do dynamic loads as I need to call the dll from a legacy application. Are there any options to change the way LV links to MFC or to force the dll to find the LV runtime?
Alan Widmer

Ben,
I have attached a ZIP of the files required to test a DLL from an MFC application. Or you can build the same application by following the instructions below. I used the numtest dll that you previously sent to me so there is no 'magic' in the LabVIEW or dll.
In VC++ select NEW. Pick the MFC AppWizard (MFC) to build an MFC application. In the wizard select
Project Name: MFCNumtest
Single Document
No database support
No Compound document support
Support for ActiveX
Default settings on the Features page
MFC Standard
MFC as a shared DLL
From the ResourceView of the project explorer, add an item Test to the IDR_MAINFRAME menu then add an item Go as a submenu item (with an ID of ID_TEST_GO)
Right click the new menu item and run the Class
Wizard. Click Add Function.. button to make a function OnTestGo()
Open MainFrm.cpp and scroll to the end of the file to see the skeleton for the OnTestGo function. In this function add a call to the LabVIEW dll. You will also need to add a reference to the .lib file and the usual extcode.h.
When you run the app you will see a window with the Test menu item. Select it and click Go to run the call to LabVIEW.
This all works great. If you now go to Project | Settings and on the general tab change the Microsoft Foundation Classes: item from 'Use MFC in a shared DLL' to 'Use MFC in a static library' rebuild ALL files in the project and run the app you get the error message:
System error 998 while loading the LabVIEW Run-Time Engine (C:\Program Files\National Instruments\shared\LabVIEW Run-Time\6.0\\lvrt.dll).
numtest requires a version 6.0 (or compatible) LabVIEW Run-Time Engine. Please contact the vendor of numtest to correct this problem.
I apologies for my slow response, g
ot distracted by some other issues.
Thanks for your help,
Alan Widmer.
Attachments:
mfcnumtest.zip ‏44 KB

When calling Excel 97 Macro from Labview 5.1, get error: cant find macro!

I have a macro written that I am trying to call from Labview. To assist in this task I downloaded an Excel Macro VI off the NI Websight. The VI came with an excel workbook that included a sample macro. I can run the example with no problems. I then modified the VI to fit what I am trying to do. I can get it to work with the Sample excel macro but not the one I created (I get an error saying it can't find the Macro). I have played with the timing and that has not worked. I have also noticed that when I use the sample Macro, it will work fine for a while then after a random number of executions, it will stop working and I will get the same error as with my Macro. In order to get it working ag
ain, I have to remove the sample worksheet (macro) and replace it with the original copy. I have been pulling my hair out for a couple of days now with this one so any help would be greatly appreciated!

I am not sure what the problem could be. The VI you speak of can be found at the following link:
http://zone.ni.com/devzone/explprog.nsf/6c163603265406328625682a006ed37d/190d1f351297ef9a862567740073e2bc?OpenDocument
I ran the program for excel 2000 on my LabVIEW 6.1 about 50 times and did not get the error you reported. Your macro should not be corrupted with use. Have you considered reinstalling excel? I liked the idea about turning off multithreading. Do you see the same behavior if you run in high light execution mode?
Jeremy Braden
National Instruments

Can I call a regular LabVIEW VI from my C# application without first creating a DLL in the application builder?

I am writing a C# application and have LabVIEW 8.2 and the Application Builder. I want the application to call different standard VIs included in LabVIEW. One way to solve this is to create a blank VI, insert the desired standard VI, have the Application Builder create a DLL and then let the application call the DLL. Something tells me there must be a shortcut to this, is there? Aren't all standard LabVIEW VIs really DLLs underneath the surface? Can I somehow call those DLLs directly?

arnold_w wrote:
Aren't all standard LabVIEW VIs really DLLs underneath the surface?
NO, LabVIEW is a programming language and contains a lot of primitives. Some VIs are wrappers for DLL's but even calling these from C(#) might be a problem.
You can exploit the LabVIEW ActiveX interface to perform all the actions you want.
Ton
Free Code Capture Tool! Version 2.1.3 with comments, web-upload, back-save and snippets!
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I am using the NI application note "Calling IVI-COM drivers from LabVIEW" I created an Automation Open and an Invoke Node, after wiring

the 2, the AN asked to right click the Invoke Node(this is step9) and choose initialize. However there is no intialize option on the pop up menu. Anything am I doing wrong? I am using Labview6 and I did add the "enableCustomInterface=True" in the INI-fileThank you for your help.
T Tall

the 2, the AN asked to right click the Invoke Node(this is step9) and choose initialize. However there is no intialize option on the pop up menu. Anything am I doing wrong? I am using Labview6 and I did add the "enableCustomInterface=True" in the INI-fileT Tall,
What's the number of the application note "Calling IVI-COM drivers from LabVIEW"? I'm unable to find what you're looking at.
Thanks,
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