LAVA: LAVA Portal

Since the RSS-feed only posts the first message of each thread, I have been relying on the View Unread Content as my feed.
However since last weekend the start date is being reset upon each visit to this page.

That screenshot is from this morning, and shows only the posts of the last night. I left yesterday without readins all the messages, now I have to digg through each forum to get all the messages.

Please fix the RSS-feed.

Ton

Hi All,

We're using labview to control a measurement system which comprises several moving axes, a source and a detector. We have a whole suite of software written now in labview for control and acquisition with the system and (separately) for post processing acquired data. One of the functions of the measurement system is to acquire 2D data "maps" and then process the data and display it to the user. For the type of measurement we're doing a dB contour plot of the data is extremely useful. At the moment, we have manage to achieve this using the 3D plots in labview (8.6). But we want to be able to make cursor measurements on the plots as well, which is where things get tricky - although we can make the 3D plot simulate a flat, 2D contour plot, the cursors within the 3D plot are always in 3D... so it's not at all obvious where on the flat projection of the contour plot the cursor is actually placed.

The ideal solution would be to have a genuine 2D plot with the contour lines on it (as opposed to using the 3D activex graphy thing), but I can't see anywhere within labview how to do this... I can get nice looking intensity plots of the data, but I want contour lines (with user selectable dB interval). Is there any easy (i.e. pre-existing) labview code that will let me do this? I can't imagine that I'm the only one who's interested in doing this with data acquired in labview....

Running inside the labview IDE I can use the MatScript node and the matlab "contour" function, but this app requires building into an exe and running under the labview runtime engine (which apparently you can't do with matscript functions...)

Anyone know any good solutions for doing this? Any suggestions welcome (I'd probably even pay for an add on if one existed... well, maybe...)

Cheers

Paul

I whipped out this tool yesterday to extract the call spec for any web services you have created in your project. This will make documenting your web calls much easier. I have tested this with all my projects that have web services in them but I would like others to give this a try and let me know if you find any bugs. I will be including this tool in my upcoming LV2010 web service tool package.

The VIs are written in LV2010.

-John

I'm a little confused as to why this is. If you could take a quick look at the code below:



The method is an override for a base class method. I need to get information from my class data, so I cast the object to the proper class. Note the cast will ALWAYS be valid (otherwise the dynamic dispatch will not invoke the method). I understand that the primitive can't have knowledge of this, but why does the prim lose the run-type type info? I can't use the output to wire up my Call Parent Method because it generates an error (as expected given the prim's behavior):



Is someone able to explain why the behavior is as it is? I've never stumbled across this problem before...

Hello all,
I had ever saw on ni.com that sombody shared user defined labview control kits(see attachments) which can build very pretty GUI, are there any other free kits to download?

Thx

Hi! 

I am wondering how to do the following Menu like in Project Explorer - (ToolStrip Control). (New - Open - Save - Save All ...)

Could you help me how to do that?

I am not proffessional in labview but trying to make an educational program. I have leaarned a lot so far from you guys in this forum.

My new problem is that i have a Tab control which has differnet data in different numeric indicators. I have also 2 buttons. I want to set them as whenever i push any of these buttons, the default values in tab control changes. Could help me in that regard?

Hi,

I am wondering does anyone know the best way to work out my P, I and D values for my level control project? Basically I am using a subvi called simplePID which I found on the NI website. I have two DAQ assistants in my program - one configured as an analog input (this input is from a cistern arm turning a pot which will determine the level of my test tank), and the other is configured as a digital output driving a pump. I havnt tried to use this program with my hardware yet due to my lack of understanding of PID and tuning the controller. I have read up a bit on manual tuning and the Ziegler-Nichols method, but I have been reluctant to try these without a bit of advise 1st. If this works will I need to incorporate pulse-width modulation to ensure more accuracy on reaching my setpoint (my pumps flow rate is 13L/Min but I have installed a manual valve to restrict the flow as necessary)? I have attached the vi below. Thanks for your time,

Rich

Hi

I got a problem with a .net DLL.
I have made a VI that use .net DLLs and it works fine.
Then I got an update of some of the DLLs.
When I open my VI and try to change the contructer node I got this error.

the version of the assembly you requested was automatically promoted to a later version by the .NET runtime engine

What does it mean and what can I do to avoid it?

I use:
LV8.2.1
Vista

thanks in advance

Bjarne

Hello,

I would like to install and run on a Windows 7 PC an application built on my developpement PC (LabVIEW 8.5.1 under XP).

I had some problems with the front panel fonts solved as described on another post by adding on the .ini file:

appFont="Tahoma" 13
dialogFont="Tahoma" 13
systemFont="Tahoma" 13

The data acquisition works normally.

The program should open some acquired data directly on OpenOffice scalc. To do that it looks on the registry the Path of scalc. There seems to be some problems accessing the registry: The vi "Open Registry Key.vi" working normally on XP returns a -604 error on Windows 7.

Any hints?

Thank you.

I found a new bug in LV2010. Back in LV8.6 I reported an issue where the order of the build specifications dictated the order they would be built when doing a build all. So, If you created an EXE first, then an installer, then later added a web service and included it in the installer, the order of the build would be:

Exe > installer > web service. Thus, when you make edits to the web service code and do a build all, your changes will not be picked up unless you build all twice, since the web service would be build AFTER the installer.

The work-around was to drag the build specs around to rearrange them so the web service came before the installer that needed it. I reported this and said that a better fix would be for the project to detect this dependency and build the components in the right order.

Well, in LV2010, not only has this not been fixed, but you can no longer drag the build specs to rearrange them and work around the bug.

So, better plan your project completely before trying to build any part of it...

Just a word of warning based on my recent experience...

If your RT code has lots of static NSV nodes and you are also programmatically opening NSV references then
you need to make sure that the behind-the-scenes init code that comes with each static NSV node
has completed before attempting to use the NSV API. If you do not then you may corrupt the SVE
and will have to reboot to recover. Currently I just do a dumb wait (30s in my case), it would
be nice if there was a way to find out programmatically when it was safe to start executing your RT code.

Daklu made an interesting point on this thread about if there is any internal standardisation of package names at NI.
Do we need naming standardisation?
I think yes, and IMO now is the time to do it with the LabVIEW Tools Network kicking off and VIPM/packages being NI's distribution method of choice.
Can we, the open source community at LAVA, lead the way for standardisation (I think yes here too)?

As for me I copied VIPM's original naming convention for all packages (.vip and .ogp), as well as what was already out there.
Along the way I added some of my own as the need arose.
I try to be as consistent as possible (sometimes I am not!)
The following are some examples of types of packages and keywords I use, as well as the name format for the package:

lib = Library: [Type] Internal Reuse Library
E.g. jgcode_lib_developer-1.4.0-1

rsc = Resource: [Type] Not reusable code. This can include palettes, templates, hooks, LabVIEW menu (wizard, project etc...)
E.g. jgcode_rsc_jgcode_toolkits_palette-1.1-1

class = LVOOP Class: [Keyword] Contains Library/Classes designed to be extended etc... (as opposed to an non-extend-able API)
icon_lib_class_variant_map-1.0-1

qdp = Quick Drop Plugin: [Keyword]
E.g. jgcode_rsc_qdp_lvoop_assistant-0.11.1-1

rpk = Repack: [Type] Repacked some else's code, need to use the code but it wasn't available as a package. None of the original code is changed.
E.g. jgcode_rpk_ni_system_style_daqmx_controls-1.0-1

fix = LabVIEW Fix: [Type] Exclusively released by NI and overwrites LabVIEW shipping files (something I don't normally like to do)
E.g. jgcode_fix_ni_apply_icon_to_vis_buttons-1.0-1

tool = Tool: [Type]: I started using this keyword for LabVIEW tools (e.g. Project Folder) but have considered dropping it in favour of rsc
E.g. icon_tool_open_icon_folders-1.1-1


Another format I have considered is for releasing code that is not quite up to production but I want to manage it's release using a package (that's a great thing about packages - they're version controlled). Haven't come up with a standard name for that yet tho.

I am interested to hear how others divide up their distributions.
What is everyones opinion on this?

I want to link a listbox to an event structure but i don't know how to assign each item in list as a case in event-case structue. It only shows the whole list box when i want to Add an event case!! how can i define each item in my list as a case in event structure?

Hello group.

My company is looking for an engineer to help us in the development of LabVIEW applications for the characterization and testing of electronic devices and electromechanical systems. Experience with PXI, CompactRIO, embedded systems and medical devices a plus. Must be local to the Miami area (South Florida) or willing to relocate. Position is a temp to hire. Please contact me at pbk[at]embedded.cl for more details.

Thanks! Regards.

This is the official release of my LV State Machine template; the TLB - Top-Level Baseline


It was presented at the State Machine vs. State Machine presentation @ NI Week 2010

This is worth using is because it implements most of the common functionality that you end up creating w/ most / all LV state machines anyway.

• Error handling
• Idle cases
• Interactive event driven execution
• Shutting down parallel loops gracefully
• String based queued states
• Handling the Panel Close? event

Some techniques used are not immediately intuitive, but each design decision was made with the idea of scalability and ease of use in mind.
Please post your 'Why did you do that?' questions and I'll gladly inform and instruct why the design choices were made (including why did I use colors)

I will be adding content to this post over time including videos and more documentation.

 ni_util_tlb-1.1.0.16.vip (773.14K)
Number of downloads: 89

 TLB – Top Level Baseline.ppt (351K)
Number of downloads: 115

Hello All

I have been away from LV programming for some time other than some quick DAQ stuff to solve a problem , well , I am back into a couple of projects and since I am starting anew I will go the LVOOP route. I used LVOOP in its early days and drove Stephen nuts back then , so , to spare him even more frustration I will ask the experts here. This is very basic , but , my memory isn't so good anymore so I need a re-fresher.

What I am doing is taking data using my DAQ Class from three sensors , Temperature , Flow and DUT output , I need to do a little processing on the data and was going to have each type be its own class , especially since I am sure the sensors and processing will change down the road. But , as I got into it , no matter what route i went down (via LVOOP) it seemed to be awkward whatever way i was approaching it and stopped and decided to see what you guys suggest , I know it is very basic but what is the best approach (design pattern) to use for something this simple.

In addition to the processing the data I also need to Graph it , save it to file etc... all the usual stuff we do with data...

thoughts...

Dan

Sales and Marketing:



Engineering:

[cross-posted to ni.com]

Howdy


This may be a VI Server question more so than a scripting one?
But any help is much appreciated.

I am running into the following issue:
I have an unsaved Class with unsaved members that I want to perform a Save All on.

If I run the LVClassLibrary.Save method first I get the following error:

Error 1019 occurred at Invoke Node in *.vi

Possible reason(s):

LabVIEW:  One or more untitled subVIs exist. This file cannot be saved until all dependent files have been named.

If I try to save each member first using VI.SaveInstrument I get the following error

Error 1450 occurred at Invoke Node in *.vi

Possible reason(s):

LabVIEW:  One or more untitled library dependencies exist. This file cannot be saved until all dependent files have been named.

Method Name: Save:Instrument

I can't seem to find a method that does everything all at once.
And I can't seem to do either one first.
Can anyone help?

Cheers

-JG

NI VeriStand 2010 expands its capabilities for hardware-in-the-loop and real-time testing by supporting high-performance, multiple chassis systems and low-cost, ruggedized options.

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