Labview display delay

There is some sort of delay between when events occur on our test stand and when they are observed on the Labview front panel. When the progam is first started, the delay is not perceptible. The longer the program runs, the greater the delay. I haven’t verified it yet, but I suspect the delay is also present in the data that is being logged. After running for ½ hour, the delay is approximately 5 seconds. The longer the VI runs, the longer the delay becomes. I have seen it where the displays are nearly a minute behind the actual event. The program is very simple and consist of a single loop that utilizes a "Wait Until Next ms Multiple" block so that it executes every 50 milliseconds (+/- 1 millisecond because it is not Labview realtime). The CPU is at about 70% utilization while the VI is runnung. Any help is most appreciated.

I would advice you to drop the Express VIs on daqmx.
The current setup will stop and start the daqmx read on every loop, this is ment is the context help of the Express VIs.
Why do you need the Index Waveform Array VI? I think a normal Index array would work. If you want to keep this vi, check that this VI is reentrant.
The write to spreadsheet file has the same issue as the daqmx VI, repeating functions (open, write, close) at every iteration.
The same goes for the GPIB drivers.
Basically you need a state machine:
Init
Initialize, the daqmx, GPIB, files
Execute
Read your data, filter, save to disk
Close
Clean up your references, stop daqmx
Close LabVIEW
I am absolutly positive you will miss samples in your current setup.
Don't use the LabVIEW Stop primitive
Good luck,
Ton
Message Edited by TonP on 06-04-2008 08:56 PM
Message Edited by TonP on 06-04-2008 08:57 PM
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Labview display problem

Hello,
The Labview display went crazy one day. When I scroll the vertical scroll bar of the front panel, only the left part (about 3/4 of the width of the screen) of the front panel goes up or down as it should, while the right part (about 1/4 of the width of the screen) freezes. Also, the problem persists when I was running my VI. But there is no problem with the block diagram window.
Is this a bug of Labview? Or could it be caused by my application/code? How could I get rid of it?
Thanks a lot,
TK Lui
Attachments:
Screenshot.JPG ‏137 KB

Thanks Tolga. But it didn't work for me. But let me describe what I did and see if it's what you meant.
I didn't manage the VIs as a project. So, I opened a new project and
add the folder that contains all the VIs (call this folder the root
folder). I then saved this project in the root folder. To copy the
front panel/codes, I went to Project > Add File to add a new VI to
the project. I saved the project by choosing Save All. Then I did Edit
> Select All and Edit > Copy to select all the front panel
objects/all codes and copy them to the clipboard. After that, I went to
the new VI and did Edit > Paste to paste the controls/codes to the
new VI.
The situation stayed the same: when I copy the front panel objects, I
lose the codes; and when I copy the codes, I lose all the controls on
the front panel.
This time I'm attaching all the codes so that you (or perhaps someone else) could try to run it and troubleshoot it.
https://netfiles.uiuc.edu/tlui/www/VIs%20for%20PBSDDS%20III.zip
Thank you very much for your time!
TK Lui
Attachments:
Screenshot01.JPG ‏184 KB

Does LabView display the Bluetooth signal strength when running on Windows XP?

I am interested in getting the Bluetooth signal strength in a Windows XP application. I would like to use the Microsoft bluetooth drivers for my application. First, Does LabView display the Bluetooth signal strength when running Windows XP? Secondly, If it does what Windows API(s) does it use to get access to this information?

Hi,
It does not seem like the Bluetooth VIs allow you to display the signal strength and I can definitly enter that as a product suggestion for the Bluetooth functionality in LabVIEW. For now, I would suggest going through the Windows API and searchingn for RSSI - Received Signal Strength Indication. I did not have a lot of luck in my searches through Microsoft, but you can give that a shot and post back with any more headway you make.
Also, you can try going to SourceForge.net. Just doing a search for Bluetooth and RSSI popped up several hits of code that has been developed for Bluetooth applications. Then, you can see about creating a DLL call to a particular function that will return RSSI information to you, to which
you can then use in LabVIEW with the Call Library Node.vi.
Hope this helps and best of luck!
Kileen C.
NI

PDF ligature display delayed in browser

I am having problems with ligatures in a pdf displaying correctly in my browser. I would love some insight as to what is causing this. Here are the details:
PDF exported from InDesign CS3 > Uploaded to website > Click on link to open > PDF displays immediately except for the letters "ff" (Mercury Text G1).
This occurs in IE 8, Google Chrome, and Firefox. Also, when I open the PDF directly in Adobe Acrobat there is no delay.
Thanks!

I'm having the exact same issue. Can't find an answer anywhere yet.

Howto fix Labview 2010 delays

My Labview 2010 causes huge delays ~30-40s when compiling and when using its restore function.
It is blocking the pc (unusable) for that time.
I tried several times now but development work with that pauses is not possible.
The System: MS XP32, Athlon64 3800+ with 2GB RAM is not recent, but clearly within the min. Requirements: Pentium 4 and 1GB
The app is first written under LV 6.4/8.0 and its using very less express vi stuff.
Howto solve the delay problems coming with LV 2010?
1. Do I need to rewrite my whole program using express Vis...
2. Can I deactivate some features to reach LV 8.0 performance....
3. Do I need faster cpu and more RAM...
4. Can I give this program back to NI because of a) missing compatibility and b) wrong minimum requirements
btw...can Labview be completely deinstalled at all...?
sorry for asking a bit agressive but this "NI program" cost me several days now for nothing
Hints esp. to Question 2 would be very appreciated...
Solved!
Go to Solution.

mwo wrote:
is that much...?
Yes, 1MB for code and 3MB for diagram objects for a single VI seems a lot. How complicated is that VI? I would recommend to modularize it a bit.
In any case, you might want to submit the code to NI, maybe there is a bottleneck in the compiler that could be improved. The 2010 compiler is much better, and I never have speed issues, even with large projects.
LabVIEW Champion . Do more with less code and in less time .

Use the LabView time delay in a while loop instead of using the instrument inherent time loop.

I have a zes lmg500 that I use. It has the option of continues measuring data, with a user control cycle loop (still using a while loop but the delay is coming from the instrument). The problem is that the loop time is not constant. Can I use a very short time (100ms) as the instrument cycle time but use a longer time delay in the while loop that collect the data?
I know many instrument offer the same abilities, so the question is relevant to all of them.
Thanks for any help
Solved!
Go to Solution.

Does that measurement VI have built-in wait functionality and a timeout?
If not, then you are simply polling the VI at 1 kHz, but I suspect that this is not the case or your Waveform Chart probably wouldn't look as you expect (getting 0's put in everytime measurement data is not available).
I expect that if you have the instrument set up to send data at a fixed time interval (i.e. 100 ms), all the data that it is sending you will end up residing in your serial buffer (or the instrument driver will have taken it out and put it in another internal buffer), so if you come back to read it 1 sec later, then you will have 10 data points to go through. Whether you can read them all at once with the read VI or have to call it a whole bunch of times until empty I can't say.
What is your objective?

MSI NF735GTX-P31 display delayed 20-30 minutes after cpu power on

I have a problem with my PC:
Motherboard - MSI NF735GTX-P31
RAM - 3gb
When I pressed power on button, CPU beep fine, but no bios/just black, only can see CPU red light blinking, the display showed after 20-30 minutes.
I have try to reset CMOS, reseat RAM and so on, it still same.
Try to flash the bios to A60, nothing changed. Still need to wait 20-30 minutes to show the display.
How can I solve the problem? Thanks.

>>Posting Guide<< please give more details to your parts!
also that board name in nonsense and doesn't exist so please check what model it is please!

Page Display Delay

Sometimes Firefox loads a page, but does not display it. when i spend a little time switching between different tabs/apps, the display appears.
my phone: galaxy note
ROM: ice cream/ jelly bean (both tested)

Try with Beta version of Firefox
*https://play.google.com/store/apps/details?id=org.mozilla.firefox_beta

MacBook Pro with Retina display delayed order

I ordered mine on Aug 7 and the status kept showing "processing order" and estimated delivery of Aug 20-27. When I called to check what was happening, I was told the order should be shipped in a day. The next day, I get an email from Apple saying "order delayed" and now the estimated delivery is Sept 9.
It's going to be more than a month since order. Is anybody else in the same boat??
I ordered from Apple Education Store.

There have ben multiple problems with various parts of the rMBPs. Screen problems to name just one. Maybe Apple is holding orders until these problem can be rectified.

Lengthy captures equals "preparing for display" delays?

Philip Hodgetts on the fcp-l posted the following "Remember too, that the project will get more sluggish, more quickly if you do many long captures instead of many more short captures.This particularly affects "preparing for display" type problems (ie makes them worse) However that has to be balanced with the total number of clip-instances in the project. The more there are overall, the slower the project will perform."
Can anyone here confirm this? Cookman and I have a running argument over the best workflow. He prefers logging and then just capturing selex. I prefer capturing everything and then logging (we both agree and the necessity of thorough logging). This may have some impact.
I recently finished a dvcproHD project where each reel was captured as one file. Each file was around 25 gigs. I would often get lengthy "preparing for display" message, but this usually happened when I was switching between going between normal editing and the switching to the apple cinema display full screen preview. I rarely if ever see this message when working with DV material so I suspect that it's a function of file size rather than "length of capture."

There is a happy medium position in the log and capture wars that is sure to please no one.
Squarebox sells a media management program called CatDv that comes with a little capture app - live capture plus.
LCP can be used as a stand alone capture app and will use the same info as 'start stop detect' in FCP to capture a complete tape and cut it into individual clips. If you just use LCP, your clips are named by reel number and time code. If you combine LCP with CatDV you get a great many more media capture, naming and storage options.
The entire tape is captured to a temp file where it is parsed and written out as individual clips. The temp clip is then deleted. I suspect the time it takes to do this is processor dependent and it does hang up the system for an extra period of time if you are running this off a G4 powerbook. You also need at least 2x the file space to allow for the processing.
It is an interesting idea in that allows the best of both worlds - full tape capture (low wear and tear on weak drive mechanisms) and small clips (fast display, simplified media organization).
cheers,
x

I want to display live video in LV, with the option to click on "delay" button, to view what happened N s. ago (i.e., a variable video delay)?

Hi. I have a standard video camera + PCI 1408. I can nicely show the current image, using LL Ring examples. I want a boolean switch so I can switch from watching the live video to the video recorded N seconds ago. My initial hope was to use LL Ring, with
lots of buffers, and copy/extract either latest buffers or a buffer several acquisitions ago. However, this seems to add no delay at all. Suggestions please? Thanks Patrick

Patrick,
What I start with is the sequence acquisition. I change it from one time to continuous, and simplify it a little bit.
I have included an example that shows how to set up a buffer and display delayed video.
One thing you have to do is open MAX and change the maximum number of buffers for IMAQ to something larger than 50. I usually select around 2000 buffers so that I never run out.
Bruce
Bruce Ammons
Ammons Engineering
Attachments:
Delayed_Video.vi ‏66 KB

Is this a bug in Installer Source Files Display

When building an installer in a LabVIEW project I added a directory under [SystemFolder] in the Destination View and it appeared normally in the Destination Window, with the - sign at the left. After exiting and reopening the Installer Builder there was no sign of this directory.
When I tried to add it again I got an error message saying it was already there.
The attached screenshot shows the error message and the (contradictory) lack of any sign of the directory being under [SystemFiles].
A similar-sounding bug was reported as fixed under LabVIEW 8.5.1 at http://forums.ni.com/ni/board/message?board.id=170&message.id=328532&requireLogin=False
George
Attachments:
App Builder err msg.JPG ‏172 KB

Hi Owen,
I'm using LabVIEW2009 Pro. Perhaps I can say a little more. I was learning to use the Builder part of LabVIEW Project and trying to get it to place a number of directories of files in a number of locations. Because of this I closed and reopened it many times as I learnt how to make it do this and added more files to the project and build as I went along. I suspect that at some point the files used by the builder of the exe file or the builder of the Installer became corrupted or conflicting. It definately happened more than once but it's hard to say now what action or change might have caused it. I intend to delete what I have and start again. Now that I know a little more about it it should be possible to get it finalised with few iterations.
As to other programs stopping LabVIEW displaying the files I'm unsure what that might be. The computer in question has a few applications installed on it. Windows XP, LabVIEW, MAX, JTAG Technologies LMTools for JTAG testing, ASIX UP for a ByteBlaster PPROM blower, Altera Quartus II v9.0 for FPGA programming, Maxim1-Wire drivers, Cypress EZ-USB, and a Seiko SmartLabel printer program. But, as far as I know none of the non-NI programs would have been running when I was using Project to build the Application or Installer.
I hope this is helpful.
Regards George

Query regarding hex format in labview

hello,
I am getting hex data in labview in the format xxxx xxxx xxxx xxxx and i am trying to convert it into number format..so is this hex format valid or do i need to remove the spaces between them before conversion to a number?..any help would be appreciated...
-innovator81

Innovator,
This can go on forever unless you are more specific (see also your other thread).
You need to distiguish what you see and what the underlying data is.
If your string display is set to HEX display, you don't have any spaces and each pair of the letters 00-FF represent one byte in your raw string. LabVIEW displays it strucured with spaces to help the eyes, but your data does NOT contain any spaces. This is a purely cosmetic property of the text indicator if set to HEX display.
If your string display is set to normal and you see data in the form XXXX XXXX XXXX ..., you real data is a humanly readable hex formatted ASCII string.
You need to understand the difference between these two cases!
LabVIEW Champion . Do more with less code and in less time .

How to reverse array display order?

Is there a way to reverse the way labview displays array data? When using a boolean array I would like the LSB to be on the right side.
I know that you can use the reverse array function, but that changes the actual data. I would rather just change how the data is displayed. Also I have quite a few and don't want to have to add that to all of them.
Thanks

It should be fairly trivial to add a reverse array before displaying the data. Keep in mind, when you display the data on the Front Panel, you can keep a parallel branch wire on the Block Diagram that is not affected by the Reverse Array.
Also, if you are displaying many of these arrays, perhaps you could use a 2D array on the Front Panel to show all bitmaps at once? Or, a 1D array that contains a cluster of the Boolean array if the Boolean arrays are ragged/jagged. Using this method would be scalable, meaning you would need only 1 Reverse Array for N arrays you want to display.
And smercurio_fc is right about the XControl being able to display a reversed array. But if you're not willing to drop Reverse Array in a few places, you're probably not willing to bite off the non-trivial task of creating an XControl (there's a moderate learning curve for getting the hang of creating a good XControl).
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Communication lost between labview 6.0 opc to rslinx

I am reading i/o tags from an allen bradley 5/05 through rslinx using ethernet settings. Everything works fine, I read and write to the tags all day. However, If I go online through the ethernet it seems like all the bandwidth is used up and labview displays an error. maybe opc times-out. When labview is retrieving just i/o through opc, it works fine. But if it is retrieving i/o and gathering analog data from a MIO card and you try to get on the plc it faults out. Anything would help. I have attached i/o read/write vi
Attachments:
NEW_OPC_Digital_Functions.vi ‏134 KB

You could try accessing the i/o on the plc using the 'Server Explorer' program. If you do not have that program you can download it at: :Server Explorer. Server Explorer is a utility that allows you to view and interact with available OPC servers. You might also try accessing the PLC from two different computers at the same time to see if it is a problem on the PLC side. There are not any known issues with DataSocket OPC like this so you might also contact Allen Bradley about the issue.
Regards,
JR A.
Application Engineer
National Instruments

Labview display delay

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