ActiveX to configure LabVIEW and webDAQ

I'm trying to use ActiveX in LabVEIW to fetch data from a webDAQ/100. I have configured the webDAQ, put I need help to communicate with the webDAQ from LabVEIW (using ActiveX). I've never tried anything like this before, and I would really appreciate some help here

Margann,
The best help we can offer is to point you to the ActiveX shipping examples in LabVIEW. This will show you how to use the ActiveX functionality of LabVIEW. If you need help deciding what methods and properties to call on the ActiveX object, then I would contact webDAQ.
Randy Hoskin
Applications Engineer
National Instruments
http://www.ni.com/ask

Similar Messages

Lost ActiveX connection with LabVIEW server

I have called LabVIEW in TestStand and tried to execute the test cases .
While executing I got the following error: ( Lost ActiveX connection with LabVIEW server.
The LabVIEW adapter will try to reconnect on the next execution attempt.-18001; An error occurred accessing the LabVIEW ActiveX automation server.).

Same error. Is anyone from NI going to bother commenting on this? It's been >8 months...

I am trying to use Labview and RP1210 compliant hardware to connect to a truck J1939 bus and receive messages.

I am trying to use Labview and RP1210 compliant hardware to connect to a truck J1939 bus and receive messages.
Specifically I am attempting to read data frames using the RP1210_READMESSAGE . am able to configure the hardware and send a message to the J1939 bus. . I think I have not configured something correctly. I can use the RP1210_SENDMESSAGE and see the message I have sent on the bus using CANalyzer When I use the RP1210_READMESSAGE I get the timestamp from a message and the return from the function sends back the correct number of bytes (the number matches the number of bytes I sent out plus four bytes from the timestamp). What I am having trouble with is actually receiving the data. I have had the same type of behavior from two different hardware (Vector CANcase XL and Nexiq USB Link), so I don't think the issue is vendor specific.
Has anyone been able to make the RP1210_RECIEVEMESSAGE function work correctly?
Thanks for any help

Thanks
I have already tried that. The links are the NI RP1210 wraper. The problem I am having is using labview to interface with the RP1210 layer. The RecieveMessage char*fpchAPIMessage this is the output which is a pointer to a cahracter array. In this variable I can receive the timestamp of the message but not the message. The retun showns the correct amount of bytes are aviaable (18 for a 8 byte message) but I can only get the 4 byte timestamp I think I have to dereference this pointer to view the data. I am not sure how to fix this.

Activex question in labview

Hello,
I am trying to controll an 8753ES with the agilent intulink through labview using activex. I have read about activex in labview, and and help file for intulink, which says:
In order to use the Agilent IntuiLink VNA Automation Server, a Visual Basic program must reference two servers. Under the Visual Basic Project | References… menu item, include the following two references:
· BLXL Servers: Check the box for Agilent IntuLink Servers Common Interfaces. As the description suggests, this library contains definitions of common interfaces. In particular, this library defines some enumerated types, used by Agilent IntuiLink Automation Servers.
· AgtServer8714: Check the box for Agilent VNA Network Analyzer Automation Server. This library contains definitions specific to the supported network analyzer products.
Object Hierarchy
AgtServer8714 Object
Provides methods to obtain data, obtain graphics, save and restore calibration and state, and to establish and close a connection to a network analyzer.
AgtMeasure8714 Object
Provides methods to obtain scalar parameters from the network analyzer. Most of these are setup parameters.
AgtUtilities8714 Object
Use the AgtUtilities8714 Object to:
· Work with the network analyzer connection to the PC.
· Work with the network analyzer descriptions and identity.
Now, I have constructed what I think is the correct implementation in labview (see atachment), but when I run it I get an error that makes it seem like an i/o refernce is not included:
Exception occured in AgtServer8714.AgtServer8714.1: CAgtServer8714::Connect method failed. CAgtCore8714::Connect method failed. CAgtConnectObject::CreateIO method failed. in vna_activex.vi
What I really want to know is, how do the references that are required for a program in vb work in labview? I looked up a vb sample for intulink, and they include four references:
Reference=*\G{00020430-0000-0000-C000-000000000046}#2.0#0#..\..\..\..\..\..\WINNT\System32\STDOLE2.TLB#OLE Automation
Reference=*\G{06EB23A2-C6C1-8714-98B5-080009C12B46}#1.0#0#..\..\..\..\..\..\Program Files\Agilent\IntuiLink\VNA\AgtServer8714.dll#AgtServer8714Lib
Reference=*\G{D753C10E-EF9A-11D3-98B9-080009C12B46}#1.0#0#..\..\..\..\..\..\Program Files\Common Files\Agilent\IntuiLink\BLXLServers.dll#Agilent IntuiLink Servers Common Interfaces
Reference=*\G{6B263850-900B-11D0-9484-00A0C91110ED}#1.0#0#..\..\..\..\..\..\WINNT\System32\msstdfmt.dll#Microsoft Data Formatting Object Library 6.0 (SP4)
It seems like in labview, there is nothing else that is reading the reference when I do an automation open. Any help at all is welcome. Also, if you know of any labview examples that use intulink, that would be great.
Thanks,
Eric
Attachments:
vna_activex.vi ‏11 KB

Here is a link to the Agilent8753ES instrument drivers from www.ni.com/idnet:
http://sine.ni.com/apps/utf8/niid_web_display.model_page?p_model_id=1625
Brian
Brian G.

How to implement an ActiveX server in LabVIEW

My task is to implement an ActiveX server in LabVIEW 8.0 that will be called from a data management software (DXE).
The LV server will take care of data acquisition and control.
I have been looking for tutorials and example code at the NI developer zone and elsewhere without any progress. Information is either to general or code is to old (LV 5.1) to give any help.
Please, show me to a good example of an ActiveX server in LV 8 properly commented or with attached explanations.
Alternatively, suggest any tutorial, short course or books with practical instructions.
Specific information is most welcome.
I suppose that it is possible to write a ActiveX client in LabVIEW to verify the functions of the ActiveX server ?

rolfk wrote:
skalis wrote:
Thank You. Good to know that I am on the right track.
However,
Your sentence "If You look at the several shipping examples..." make me
little concerned. I am not able to find any example of a LV ActiveX
server in my LV 8.0 installation. I would be very grateful of You can
send me any.
Basically you can not create your own
Active X server with your own object hierarchy and methods in LabVIEW.
LabVIEW however can export a predefined Active X server interface that
is just another access method to its internal VI server interface.
With this interface you can determine what VIs are available to
control, load specific VIs from disk if you know their path and,
execute those VIs and passing parameters to it and receiving outputs.
So if your software allows you to script the Active X access to an
Active X server in some ways such as VBA or similar you should be fine.
If your software expects a specific Active X interface you have to
implement in the server application, you are out of luck with LabVIEW,
without using an external component such as an extra Active X server
DLL that translates between the expected interface and the exported
LabIVEW interface. But this last method is quite likely not worth the
hassle.
Rolf Kalbermatter
While I did follow the link mentioned above and found the Interop.LabVIEW.dll that is included in the C# project for the purpose of calling VIs from C#, I am frustrated that these methods are 'buried' in a .dll that you have to go and find on the NI web site, and are not ActiveX methods that are available in an ActiveX Object that is installed when you install LV 8.20 PDS.
Rolf, I don't know that you will get this email, but are you refering to the methods inside of the Interop.LabVIEW.dll in what you are saying above, and if so, how did you become aware of this .dll?
Is anyone aware of any documentation for these ActiveX methods?
Thanks,
Wes
Wes Ramm, Cyth UK
CLD, CPLI

I am new to Labview and was wondering if it is possib

le to control Labview via an external script? I am trying to automate my testing and want to use a script to send commands that will call my equipment.vi models and have it configure the equipment via GPIB to the test instruments. Thanks in advance - HeidiI am trying to automate my testing and want to use a script to send commands that will call my quipment.vi models and have it configure the equipment via GPIB to the test instruments. This will take out the GUI interface and still allow my model .vi's to control my equipment. - Thanks in advance - Heidi

le to control Labview via an external script? I am trying to automate my testing and want to use a script to send commands that will call my equipment.vi models and have it configure the equipment via GPIB to the test instruments. Thanks in advance - HeidiHi Heidi.
Check out this link from Jeffrey Travis
http://www.jeffreytravis.com/lost/labperl.html
"LabPerl is a cross-platform API for letting LabVIEW and Perl communicate. It consists of some LabVIEW VIs and 2 Perl modules (.pm) files that allow Perl functions to call LabVIEW VIs and pass data, and viceversa. You should be somewhat familiar with Perl before trying to use LabPerl."
I do not know if it will do what you want as I never tried it, but it is worth a try.
PJM
Got EasyXML?
JKI.VIPM.EasyXML.OpenG.LAVA.Builder.blog

How to switch central frequency fastly with labview and USRP?

Hello everybody,
         Recently I was making a frequency hopping receiver with labview and USRP N210 and SBX. The transmitter works on the 2.4G band, and it changes from one central frequency to another every 65536us. As I think, if I start receiving at the correct time, and change the central frequency of the USRP every 65536us, I should be able to receive the data.
    But I find that, when usrp switch form one central frequency to a different one, it spends nearly 48ms and when it switch from one frequency to the same one, it only spends 3ms(I test the performance by modifying the niUSRP EX Rx Continuous Async Reconfig on the Fly.vi example). So if I want to follow the hopping sequency, I may can only receive 17ms data because I have to save time for switching central frequency.
     My problem is that: why usrp changes central frequency so slow, how can I make the process faster? If I want to follow the hopping sequency, can anybody give me some good advice? Thanks

There is an attribute "LO Frequency" that you can use to lock down the frequency of the local oscillator. Then, when you set the "Carrier Frequency" attribute, the difference between the carrier frequency value and the LO frequency value will be realized by frequency shift in the DSP in the FPGA. Changing this "digital" frequency shift value is much faster, since you don't have to re-tune the local oscillator.
Let's say you're sweeping from 2.44 GHz to 2.46 GHz. Set the "LO Frequency" to 2.45 GHz then Commit. Then, in your loop, program the "Carrier Frequency" attribute from 2.44 GHz to 2.46 GHz. In the loop, it will only program the digital frequency shift, which will happen much faster.
Another tip is to use the property node to program only the attributes you want to change, rather than the niUSRP Configure Signal.vi (which sets many at once).
For more details, see the "Configuration:Advanced:LO Frequency Property" in the NI-USRP Help, and look at this example:
<LabVIEW dir>\examples\instr\niUSRP\niUSRP EX Fine-Tune LO Frequency.vi

How can i use activeX Control in labview?

how can i use activeX Control in labview?
please describe me step by step.
thanks.

Well..that was quite helpful..but now I'm encountering certain problems. I've attached the VI I've made.
I don't need sound at the moment so I dropped it. (Although I tried to play it..but all I could hear was a very annoying sound.) Secondly I don't want to display any date or time..so i dropped that property too.
Now when I run this Vi...the webcam turns on, the screen of videocapx pops up..then the webcam light goes off..and another pop up appears saying..labview is not responding..and i have to close it reluctantly.
I haven't placed the stop capture property in this vi. i checked it by placing it too..but that doesn't work.
I would like to notify that my actual task is to acquire image and then compare it with another one already present on my pc. I want you to please help me out..solve my first query then I'll proceed with the latter part.
Attachments:
activexvideocaps.vi ‏20 KB

Large applications - Labview and other programming languages

Hello Labview Users,
as the forum saw this very interesting thread about large applications programmed in Labview
(see: http://sine.ni.com/niforum/niforum?requireLogin=False&forumDU=http://forums.ni.com/ni/board/message?... ) I would like to ask the community about their experiences with Labview applications in combination with other programming languages.
In advance: I have several years of experience in programming Labview applications starting from quick-and-dirty solutions which had to run within few hours and complex test solutions. I saw Labview growing and becoming better with the released versions and lot of things I missed in former times got implemented in the meantime. Actually I have to develop a complexe ATE solution with numerous equipment to control and numerous data to be captured and archived. Despite the Verison 8 I still feel still some drawbacks of the LV concept which let me hestitate to setup the solution completly in Labview:
1) It is alway hard to re-use code of complex applications since it is not possible to do some kind of global search an replace of functions
variables etc. It nearly impossible to re-use approved code structures (e.g a state machine) if the "inner part" is changing more the a little bit.
2) If the application requires a certain flexibility (e.g. exchangeable test equipment of varying vendors) this is hard to implement since you have to define a lot of parameters through your hierarchy if you dont want use global variables which slow down your application and hide
the code functionality.
3) Despite modern PCs the look and feel of LV applications appears somewhat slow compared to other applications. For complex user interfaces the polling methode generates a lot of complex code. (I dont have expierence with the event-structure).
Now my questions:
Do you have experience of implemention of complex solutions dividingthe code modules using Labview and other languages? Which other
languages did you use? Why did you use these languages (speed, flexibility of text based code, available library functions)? Did you found out this to improve your development time and code maintainibility?
(I concider a solution where I do the single tests with Labview-VIs but delegate all the test sequencing and data collection stuff written in PERL which allows really very compact code)
I'm curious what your experiences are.
rainercats

Given that you're asking these questions in a forum for LabVIEW users the opinions given are going to be somewhat slanted towards the general like of LabVIEW. I've been working with LabVIEW for a long time, ever since 2.something on a Mac. I've written numerous large-scale applications as well as "mundane" instrument drivers. As you've noted you're experienced with LabVIEW, so you know some of its strengths and weaknesses.
To address your specific questions:
(1) Yes, that has always been a limitation in LabVIEW, but I don't believe it is an overriding one to choose C over LabVIEW. Putnam provided one workaround for the search and replace of VIs. Once you've programmed in LabVIEW long enough you get used to doing it this way. Is it clumsy? Yes. As for the re-use of code structures, that's not entirely true. You can create a "template" VI (a regular VI, not a .vit) that contains the code you want to re-use and place in your palette with the "Merge VI" option set. That way you can select it from your functions palette, plop it down on your diagram, and you get the "template" VI's diagram placed right into your new VI.
(2) This is not something that is specific to LabVIEW, as this exists with any programming language. It's not the language that limits you here, it's how you've designed your code. In a language like C++ you would go with classes. You can do the same thing in LabVIEW. IVI is another option (though not preferred by me).
(3) As Putnam mentioned, you should be using the event structure.
Other thoughts:
The biggest strength I see with LabVIEW is that each VI is a miniature program, which allows development and debugging of functions a snap. With a language like C you have to write another program to call that function in order to debug it. The biggest weakness? I would say user interface. Yes, even with the event structure. Don't get me wrong, the event structure has vastly improved the way user interfaces and event handling in general are done with LabVIEW, but it simply doesn't hold muster to a program written in C or VB. ActiveX anyone? LabVIEW still doesn't do ActiveX properly in terms of actually getting the controls to work. Programming ActiveX controls is just plain aggravating what with all the property nodes taking up so much diagram space.
It certainly makes sense to use the best tools available to you to get the job done. In my recent projects I had to write software to run automated tests on some products my company made. The test modules were written in LabVIEW. The tests executive was a proprietary engine driven by a SQL Server database. I had to write a "wrapper" DLL that interfaced between the LabVIEW code and the executive since the executive hadn't been designed to call LabVIEW DLLs directly. This allowed us to use LabVIEW as the preferred language for developing the test modules and let the guys who were fiddling with the test executive do their bit. Of course, TestStand's premise is basically that.

Win 2000 attempts to "configure" Labview at startup

When starting Labview 6i, windows 2000 displays a message which says it is "configuring Labview", after thaT I get an error message: Internal error 2602 File llbedit.llb.2EB22F05_3959_11D3_80B2_0050049FD550. What could be causing this? After I dismiss the error box, the program appears to run correctly.

I believe that the LabVIEW installation may have been corrupted. I've heard of a similar issue with Windows NT, and a reinstallation fixed the problem. I would suggesting completely removing LabVIEW and then reinstalling.
J.R. Allen

Labview and Adobe Acrobat output

We currently can print (one at a time) a vi graph to Adobe pdf format,
where each instance promping for a file name. Having hundreds of data
acquistions, I would rather have a solution that prints to PDF files with
no
subsequent prompt for the user. Is there such an animal?

In response to your exact question, I don't know, if the filename is generated by you as a prompt in LabVIEW, then you are well on your way. If it is prompted for by the system, then good luck. Not having worked with this before, I can't offer much.
However...
If what you are trying to do is, as some others posting here, to print a graph periodically, then I can offer an alternative suggestion:
I once created a strip chart recorder program in LabVIEW 5.0.1. It took data at a configurable rate, and compiled it to a color graph. Periodically (also configurable, in number of data points???) it would print a b&w graph of the data collected in that set. At the end of a period, I would have a stack of neatly printed graphs, just like a strip chart record
er (sort of...)
The trick to doing this was to call a different VI with configured graphs, all neatly put up on a page, and populate the graphs with the latest data, and programmatically print the front panel. This allowed incredible flexibility with certain restrictions. As this was a front panel, you couldn't (in my version) easily configure the number of channels. All graphs were individual graphs, and were autoscaled, or scaling was manually configured. Additional information such as filename (data were also saved to disk at the same time it was printed), date, time, and other pertinent information were printed on the graph printout. It was quite inexpensive, and until daylight savings time, was quite reliable (good old windows 95 liked to shut down the system to tell you it was changing the time, and hold everything, waiting for you to say "ok"...gotta love it...)
This is an excellent method of producing strip-chart recorder type output to a printer without much fancy p
rogramming. While it does take a little bit of planning to execute properly, it really works well.
Hope that helps

Slow imc COM (ActiveX)-libraries inside LabView

Hi
I'm using the imc COM (ActiveX)-libraries inside labview. The key command is the "automation open" block from LabView and selecting the desired ActiveX class.
Here his the definition of one of this function:
Function DChannel.GetDataDouble( StartIndex As Long, Count As Long,
Data As Double() ) As Long
Copies the specified samples in an array of 8Byte real numbers.
Parameters
StartIndex
Index of the 1st sample to copy. The first sample in a channel has an index of 1.
Count
Number of samples to copy.
Data
Array to receive the values. See remarks section.
Return Value
Number of valid samples in <Data>. May be smaller than <count>, when there are not enough samples in the channel (StartIndex + Count -1 > Length).
The problem and also question is why the parameter Data apears as a variant when I use a invoke node for the above method (should be double()??)
When using large Data arrays the libraries are very slow in comparison with VB6. I tested the same functions in VB6 and LabView. In VB6 the COM libraries are very fast! Does anybody know how to improve performance with COM Variants?
Thank you

I'm not sure you can do anything about the speed as long as you use ActiveX. At least that was the answer I got when I asked a similar question here. It seems that there is a lot of data copying between memory spaces that goes on between ActiveX and LabVIEW and, if there is much data involved, it can take a while. Search these forums for the terms safearray or "safe array" or marshal data and you will find more info on what you are up against.

How can I configure labview for communication with Modbus I/O?

i read a article about configureing Labview for communication with modbus I/O in NI developer zone, but it was written for Labview 6, how can I configure it with labview 7. it seems there are some difference. Thanks!

In both LabVIEW 6 and 7, you connect to modbus using Lookout Protocol Drivers (LPD) and then communicate to LPD using the tag engine of LabVIEW DSC or through DataSocket.

Simulink, Labview and DLL

Hi all,
I can communicate my model in Simulink with Labview using the SIT and without working in real-time. However,now, although I have made a DLL(Dynamic Library Link) with Simulink and my compiler, I don´t know how I could run it in real-time with my target calling the DLL.
This is, instead of using my model (*.mdl) in Matlab, I want to use the DLL but I don´t know how I must call it from Labview.
If someone could help me, I would be very grateful.
Thanks
Ziman.

Hello,
considering that you have recent versions of LabVIEW and SIT, you could do that ( run the model in an RT target ) using the SIT Connection Manager ( Tools - SIT Connection Manager ). In this dialog box, you will have to select Real-Time Target, insert an IP and choose the path to the Model DLL. Once configured, then click on OK button and when running the VI, it will download the model to the RT Target
If you open an example that comes with SIT called Sinewave ( Help - Find Examples ), you will have the information to run it in an RT Target in the front panel. For more information, here you have a link ( http://zone.ni.com/devzone/cda/tut/p/id/3583 ).
I hope this helps
crisR

How can i work simultaniously with labVIEW and Excel ?

Hello . I study engineering and need some help with labVIEW, and the connection to microsoft excel.

Hi
NI offers an "Report generation toolkit". You get some VI's with this toolkit and so you can directly create your reports from LV.
Another possibility is the communication through ActiveX. There is a nice link with application notes and LV examples for that:
http://zone.ni.com/devzone/devzone.nsf/webcategories/C3E56C69D399361E86256AB7006A9149?opendocument&node=DZ53003_US
Regards,
Luca

ActiveX to configure LabVIEW and webDAQ

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