LAVA 1.0 Content

Do User Events run in the UI thread?

Naive question, but I've always associated User Events with the UI thread (because of the name). I've been using almost the same pattern, with notifier functions in place of the user event functions.

Sawadee krop, and welcome nipon!

Very nice, cleanly written and responsive :thumbup:

Now I must look for my Carabao MP3s to test this further. Maybe you should have included at least part of "Made In Thailand" with the ZIP file

(Note: For others who download this, I loaded player with LabVIEW 8.2 and would crash when running the top level vi. I noticed that nipon's primary LabVIEW version is 7.1 and used that; it worked fine.)

CITATION(Ben @ Feb 28 2006, 05:12 PM)

The lack of positive is bad enough all by itself.

I totally agree with Ben. If for 100 posts a member get only 1 or 2 good rating then it mean he is not really bringing usefull knowledge with his posts.

The lack of positive is, IMO, worse than a negative rating.

QUOTE(NadavC @ May 1 2007, 11:37 AM)

I need a way to close a LabVIEW Exe file that has been terminated brutally by some error that I can't register or handle. Assume that the Exe file stopped running and that the GUI is still open (But isn't running).

Are you running multiple instances of the same exe, or are these different exes? If App1 contains a brutal error that you can't register or handle, you're gonna have to modify that code somehow, so why not try to identify and fix the bug(s)?

If this is a legacy app that you can't touch (regulated or source is incomplete), then the suggestions (TCP/IP, Shared Variables, VI Server) are not viable; these require changing the App1 code. Your only choice seems to be forensic methods such OS calls (CPU load, memory usage) or file monitoring (data log file stops growing, exclusive lock on file).

If you can make small changes to App1 (but aren't prepared to find the root cause of the crash) then the various suggestions should work, but you might need to install and configure the Shared Variable or Data Socket Runtime engines. If you're deployed on multiple machines, this may require more administration and/or documentation.

CITATION(lkranker @ May 2 2007, 12:45 PM)

The image type is Grayscale I16 if that helps (before I export). When I do a histogram of the image the values are between 0 and 4095. I did not test this using MAX as I am not sure how to do that.

From 0 to 4095, this is 12bit resolution, if you check the NI camera advisor, you'll see that you can't get more than 12 bit resolution (http://sine.ni.com/apps/we/nipc.specs?action=view_specs&asid=1102&pid=6843&tier=3)

CITATION(lkranker @ May 2 2007, 12:45 PM)

This is surprising... I never noticed such issue.

I'll try to test this and let you know... at least now you have a work-around.

Edit :

Hmmm, after having a closer look to your images, my best guess is that the issue is a byte inversion (little endian / big endian) I bet that the "save TIFF image" function has a setting for this !

QUOTE(crelf @ May 1 2007, 05:21 PM)

Think of your three best friends - if they're okay, then it's probably you...

But I only have two best friends; and they both exist in my mind

QUOTE(Eugen Graf @ Mar 19 2007, 11:40 AM)

Really? And why not in LV 8.0? I need more Information about it.

Why the support of texture depends from LV version? OpenGL should support textures undependly of the version of programming language. Don't it?

Thanks, Eugen

The problem is, that in LabVIEW 8.20, the picture control works with a "new" Indicator, which is not backward kompatible...

CITATION(lkranker @ May 2 2007, 05:47 AM)

I have written a vi that currently acquires data from a camera. The image steams in continuously in 16bit. I have a case structure that snaps the image and exports a single frame of the streaming image to a tif format using "IMAQ Write TIFF file". The tif file that results however is extremely low contrast. I am guessing that I need a conversion before exporting to tif, but I am unsure how to implement that. I am considering using "IMAQ Cast Image". Is there a better way? I don't necessarily need to use tif, so if there is another better method, I would be open to suggestions. If I do need to use cast image does anyone have recommendations for "# shifts" or "image type" that would work well for tiff?

Any and all suggestions would be greatly appreciated!!!

(Cast Image is shown in the pic)

Hi,

What do you mean by "extremely low contrast" ? Could you post an image ?

Before trying to enhance you image through the soft, maybe you could try to put some more light on the object you taking pictures of. Also, if the image is too dark you can increase the exposure time. By the way, what camera are you using an d how did you set it up ?

You can also check that you images are really 16bit using the IMAQ histogram, depending on the camera file (*.icd) you are using (you can select it in MAX) you could be saving an 8bit image into 16bit TIFF...

Hope these thoughts will help.

QUOTE(NadavC @ May 1 2007, 10:22 AM)

While App1 is running it sometimes generates an exception and is aborted. The problem is that the Run-Time APP1.exe GUI remains open (Which is undesirable). I need a way to close it somehow.

When I want the front panel to close on my exe vesions, I add this bit of code in my top level vi. I wire an error out to the outside of the sequence structure to keep from exiting prematurely. This has the advantage of NOT closing automatically if I'm in the development environment. I've had this for so long that I can't recall if someone gave it to me or if I recreated it from an example elsewhere. It uses the Quit LabVIEW function, which states that it stops all running VIs and ends the current instance of LabVIEW. Separate runtime exes should have their own app instance, so "app2.exe" in your case should continue to run...

QUOTE(JFM @ Apr 27 2007, 02:23 PM)

:thumbup:

/J

Are you sure that they are not just april fools??

JP,

Were you shocked that the batteries were not included??

LOL!

QUOTE(Eugen Graf @ Apr 25 2007, 02:41 AM)

Are there any possibility to adapt the data type(e.g. by variant), I can use this VI for every queue?

Yes, you can replace the string constant with a variant control (see attached). Wire the desired queue type to the input, and LabVIEW will coerce to this. Note that the queue will now be of type variant. That means that when you dequeue you will need to know the data type of the queue in order to use the Variant to Data function.

QUOTE(Submeg @ Apr 25 2007, 07:34 AM)

Ok, I have just completed a 3 day course at Uni that introduced us to LabVIEW. We now have a project to complete. I'm trying to get started but am already stuck

What I am trying to do is:

I wish to have three buttons on the main VI. When one of these is clicked, It takes you to a subVI. I want to be able to return from this subVI back to the main.

I have been trying to use cases, but is this the best way to go about it? The course was quite quick and I'm a bit lost at the moment.

Any help would be appreciated.

Regards,

Submeg

you can try it with the event structure...

have a look at LabVIEW examples...

The detailed help also points 2 example applications :

• Examples\Vision\3. Applications\Battery Clamp Inspection Example.vi
  
• Examples\Vision\2. Functions\Calibration\Simple Calibration Example.llb
  

They demonstates the way to use these metadata which, apparently, can only be "overlay information, pattern matching template information, and calibration information"

Hope this helps

CITATION(Aitor Solar @ Apr 23 2007, 11:15 AM)

That VI is done with LV7.1.1f1, and the error alert before crash says: "The exception Breakpoint. A breakpoint has been reached.", that is also pretty strange, I think. I don't have any LV8+ connected to the web to check if it works, so I'll trust you . Probably just a bug that was corrected in later versions.

Saludos,

Aitor

I've just tested your VI with my LV7.1.1 and I get same behaviour as with LV8.20.

No crash, no error...

CITATION(Aitor Solar @ Apr 23 2007, 10:15 AM)

... since just "http://www.google.com''>http://www.google.com' target="_blank">http://www.google.com" provokes a LV crash. Strange behaviour, by the way

Nice and simple solution Aitor !

What is you LV version ? Because with LV 8.20 the is no crash with "http://www.google.com", I just get no result and no answer... but no crash !

QUOTE(crelf @ Apr 14 2007, 01:18 PM)

Unfortunately, I don't think ignoring a user works if you get the "-ALL OF LAVA-" RSS feed (?)

I knew I would use this technology some day...

Yahoo!Pipes to the rescue! My custom feed is here. It's published and you can use it...

http://pipes.yahoo.com/pipes/pipe.run?_id=...amp;_render=rss

I experimented with my desktop PC, a Dell Optiplex GX280. It has PXE support, and a PDF file from the Dell web site explained that the client only needs to enable the PXE boot in the BIOS, then set the boot device order with the Ethernet first to have it get an image from a tftp server. The rest of the setup is on the dhcp/tftp server. I set my PC to boot to ethernet first, then HDD, then CDROM then floppy. We use DHCP for our office network addressing, and the PC got an IP, but there was no bootp service running to tell the PC where to look for the tftp server. The PC timed out and finally booted to hard disk.

If the "factory defaults" don't include the PXE and a boot order that include the ethernet, then this probably won't work for you. Maybe you could load your temporary OS and apps on CF and then boot the system the way it would be booted in the field. You would prove that your CF interface is working, and that your BIOS is set up to work when the SBC is deployed...

If the SBC has a floppy drive, you could look at using something I found today called "PXE on Disk". Unfortunately, they tie the bootable floppy to the MAC address of your ethernet. You would need to get a site license ($500) but these are renewable on an annual basis :thumbdown: Maybe give them a call and see what they can suggest...

The last choice would be to install an expansion card that would connect a CDROM or IDE disk drive to your SBC. I used one of these in a VMIC setup, but had to install a P2 connector across the backplane to complete the connection :thumbdown: This solution SUCKED and did not work in one of our VME chassis. It took WEEKS to get this piece of cr@p to work...

Best of luck, and if you get something working, keep us up to date. I've developed a recent interest in (re)learning about linux and how it applies to LabVIEW.

CITATION(Nullllll @ Apr 20 2007, 11:14 AM)

Hi ,

I want to ask u if labview has a feature of sending email , I mean I want to send that VI to an email by labview , can I do that?? can u plz help in that topic ?

Hi,

I don't know what version of LabVIEW you have, but in LV 7.1 function palette, you have a subpalette for SMTP email, see screnshot below :

I hope this helps

CITATION(spacecharly @ Apr 20 2007, 10:59 AM)

Hi !

It's probably quite easy but I didn't found out the solution to this question:

How to get the 'config file' PATH out of a 'config file' REFNUM ?

Hello,

There is a function for that : "refnum to path" to be found in "File I/IO" > "Advanced" > "Refnum to Path" at the bottom right, see screen shot below (LV 7.1) :

Hi,

It works fine when I opne the VI in LV8.20 but when I open the VI with L7.1 I only get a green window instead of the video... Any idea why ?

CITATION(Jim Kring @ Apr 19 2007, 02:31 AM)

http://www.mozilla.com/en-US/thunderbird/''>http://www.mozilla.com/en-US/thunderbird/' target="_blank">http://www.mozilla.com/en-US/thunderbird/

For some reason it's not available from the update in Thunderbird 1.5...

Have to get it from the website.

@ Jim :

If you run short of ideas for your articles, let me suggest :

- I couldn't live without Thunderbird

- I couldn't live without Firefox

Just kidding of course... I never miss your articles, they always teach me some new tricks !

Do your single board computers have a BootROM? With this number of UUTs, you might be better off figuring out if/how to get your computers to boot to a server that contains your DSL boot image instead of moving the boot image around.

I worked for a CAD/CAM company MANY years ago, and we regularly sold diskless Sun clients that had lots of RAM (at the time) and we would boot these from a server image, then load the application software over the network into memory. This was all Sun proprietary stuff. We created a swap file in memory to reduce the network load and maximize performance.

I did some quick searches, and I think you would want to determine if your SBCs are PXE and/or Wake-on-LAN capable. If they are, you might be able to configure the BootROM to acquire a DHCP network address, then rertrieve a boot image from a tftp server.

http://www.kegel.com/linux/pxe.html

http://syslinux.zytor.com/pxe.php

http://www.faqs.org/rfcs/rfc951.html

I too wrote this quickly, so let me know if it doesn't make sense.

Well... I didn't know that either and I'm interested in knowing the ratio of performance gain !

But I am surprised, I recently attended a NI conference on streaming, they gave many tips and tricks to obtain the highest data flow possible but they did not mention the WIN32 API... Does it mean there are other hidden drawbacks ?

Have any of you looked at the Win32 file I/O functions included in some of the newest Developer Zone examples? (example: NI-SCOPE Stream to Disk Using Win32 File IO). I've seen a few of these pop up in the What's New RSS feed, and just started looking at them today.

The consumer loop continuously empties data from the queue and writes data to disk using the LabVIEW primitive Write to Binary File.vi. The file is opened using the Win32 Open File.vi, which disables Windows caching during the write process, resulting in increased performance. However when Windows caching is disabled, data must be written to file in a multiple of the sector size of the disk (typically 512 bytes).

I don't use the NI-SCOPE or NI-FGEN instrumentation, but I do log data to disk at a high rate and can appreciate a performance boost/CPU load reduction. I understand what the VIs do and how they work, I'm just curious if anyone else has looked at them. I ran the included benchmarks on my desktop and the Win32 performance is better.

I'm mostly concerned about creating a runtime version of my app with these, and what might happen if say, a Windows service pack comes along that changes things...