I am trying to achieve as high speed as possible when sending data over the network using shared variables.
I have created a small test application as seen below.
The test sequence consists of writing an array of I32 to a shared variable (so far located on my local machine) and then measure the time it takes before the same array can be read back from the variable.
When I run tests I observe a behavior related to the size of the array. When writing an array larger than 2033 elements the average read+write time is around 0.8ms but when using a smaller array this time increases to a whopping 31ms. This behavior must be related to the built-in transmit buffer which holds 8kB, but why is the difference over 30ms? If the buffer isn't full the data should still be sent within 10ms? there has to be some additional delay related to smaller amounts of data?
In my project the data will rarely fill the buffer and I do not have access to the Flush.vi of LV 8.5.1. Is there another way to speed up the transfer?
I am having a problem with data transfer on RT target using global or local variable. My system configuration is: 128 AI channels (4 CRIO 9205) with 2000 Hz sampling rate.(I am using 3M FPGA and 9014 RT controller) I am using DMA FIFO for data transfer from target to host (2 DMA FIFOS) and read 100 ms or 200 samples on RT host. I need to transfer data to HOST PC for analysis. I set up a TCP/IP connection between RT and PC. All works fine when I send data that I read from DMA FIFO in the same loop . What I want is to have a communication loop that runs in parallel with main loop and sends data to the PC. I tried to transfer data using global or local variables but I have encountered a problem of data loss somewhere in that process. My data loss is always on 200 -th, 400 -th etc.. point (I belive that it has to do with reading blocks from FIFO??). What can be the problem.
I need to write a LabVIEW installer that will reboot and resume the install process by executing a known exe. Is there a way to do this in the LabVIEW installer or can one write a batch file or script that will invoke reboot and then launch the target exe?
I was thinking of getting WISE installer or Install Shield to help do this. But then this reboot and re-run feature is the only missing thing in my current installer.
National Instruments LabVIEW, CompactRIO and PXI platforms have received eight awards and honorable mentions from leading industry trade publications.
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Hello, I am new to LabVIEW and Databases and I am trying to evaluate T&M DatabaseWizard tool kit for LabVIEW (I downloaded the student version). But the help menu is not as explicit as I would like. So far I've been able to connect, write to and read data from a table in MS Access. Now, I can not understand, exactly, how the TM_DBTLK_Express Update VI works. What I can understand from the help menu is: I have to select a column from the table and specify the criteria that the Update VI will use to search for, row by row (I GUESS). Data matching this criteria will be overwritten with a new value that I GUESS I have to specify in the Data In port of the Update VI. BUT if I select (in the Criteria Menu) >= 41 and select the Input Data In to be 0, then EVERYTHING (the whole field) is overwritten with 0, but the field has values ranging from 5 to 41 and 333
Does anyone have experience working with this toolkit, and can give some advice? There is an example in the help menu, but is not in english. Does anybody have the example or a tutorial or manual, in english?
Thank you, your help is very much appreciated.
searchInfo.
Last post made by: searchInfo on Yesterday, 07:11 PM
Last week I had to interface an application with a game controller. The funny part is that it uses the joystick buttons to select a target region with the cursors of a graph, Up/Down arrows to select the power and the buttons to trigger a real laser. The goal of the "game" is to flatten those nasty bumps in the transmission curve of a fiber grating by selectively laser heating offensive regions.
The need arose from the fact that the application required a lot of mouse clicks (place cursors on target, set power, shoot; many tens of time) and there was a shortage of valid wrists to operate. I did already provided few keyboard shortcuts but it was not enough. The integration of the game controller was relatively easy. I plug the USB device and the Joystick VIs worked immediatly. I wrote a Joystick monitor to poll it and generate value change user events for buttons and controls. These were catched in the user event loop of the application to programmatically move cursors or signaling actual FP controls.
While the joystick provides integer values ±32000 for the position, I noticed that it didn't always come back to the same idle position, with errrors up to 3000 counts in position. Is that a common behavior for game controllers of are come controllers are better than others?
Hello All, As i'm very much interested in Learning Labview (I'm a Beginner!),i found a website that gives online learning videos. The website is "http://www.fafiles.com/".They are mentioned that if we pay the money then we will view their online videos for learning. Questions:- 1.Any body have any experience about this service? 2.Is this a trust source for learning? 3.If anybody who used this source, please advice me ...shall i go ahead or not? Thank You very much!
I thought I had some encoding/decoding VIs at one time, but can't seem to find them now. I've done countless internet searches of LAVA and other sites and all I found were links that led to nowhere.
Does anybody have any base64 encoding/decoding VIs that they would like to share, or could point me to? I'm also looking for some various checksum VIs, but I haven't searched for them yet as they may be more readily available.
For some reason I can't get my OpenG commander to work on my work desktop. I don't know if our IT department has locked down programs from accessing the internet or FTP anymore. It used to work, but when I tried to use it today, it wouldn't work.
Last post made by: Jim Kring on Yesterday, 07:22 PM
When developing with large LVOOP projects or small LVOOP projects with lots of class dependencies clicking save all button (Save all this project) is disaterous. LabVIEW consumes tens of minutes on my dual core laptop doing something on a project that does not contain any changes. What does LabVIEW do when I click the save all button? Why does it actually do something even when nothing has changed. The same thing does not happen if I use Shift + Ctrl + S (Save all) instead.
The following screen capture is from my laptop when LabVIEW has been not responsive for the last 10 minutes. LabVIEW consumes all of the processor power of another processor. Luckily I've two of them and LabVIEW compiler is not multithreaded.
EDIT: Is this the same process that occurs when one tries to close LabVIEW OOP project and LabVIEW takes tens of minutes to close?
I'm having a problem of running multiple activeX instances using LabVIEW (apparently the problem occurs with more than 4 instances). This problem doesn't happen when I do the same thing in C (Visual Studio). I can create as many instances as I wish, but when I run methods that hang or run for a long period of time, only 4 are able to run at each moment. If I stop any one of the methods, the next one starts running. I attached an example (in LabVIEW 8.5.1) of using the excel activeX automation, but it happens with all of the activeX's I tried so far. It even happens when using several different activeXs. Please notice, that the problem is not with creating the instances, but when running methods of the activeX in parallel at the same time (If you run short methods that finish executing fast, you won't notice the problem).
I recently ran into an issue that I thought I would bring up on the LAVA forums.
When dealing with clusters, I have had situations where I would like to access property nodes on specific controls within the cluster. In the past, I have used the Label.Text to identify the desired control and eventually migrated to a enum typedef representing the "order" of the control. This would allow me to rename the labels without breaking my code and upon re-ordering the cluster, I could just update the typedef which would apply all changes on a global basis.
Are there any other ways of obtaining a strict reference to a control of a cluster that is "absolute" (I don't have to search for the Label.Text in a for loop or use my enum method)? I find it interesting that I can create an implicit reference, yet I cannot obtain a refunum from this property node.
I'm new to SQL and i'm facing with following error:
using "Example - Insert into a Table.vi" to add a record in Access2000 DB composed by only one table named "Section" with one numeric field named "ID". When I run vi with following Command Text "INSERT INTO Section VALUES (1)" get this error code "-2147217900 Exception occured in Microsoft JET Database Engine. Syntax error in instruction INSERT INTO".
Now I change the name of the table from "Section" to "AAAA" (but any other name is fine) and with the same command (replacing only table name) the error disappear and the values are correctly writed!!!
Seems that "Section" is not a valid name for a table using LabSQL...or i'm missing something, i'm not experienced with SQL.
I cannot change the name of tables in DB because are used from other programs.
hai bro i'm new member in this forum.this my 1st post and i hope i'm not in wrong place. can someone tell me how to make a simpple ecg or heart rate monitor? And someone can tell me about the result of the ecg can be transfer to other pc with labview,can you tell me about that and haow to make it with labview?Where i can find the complete ebooks and free project of labview? I hope you can help me bro by the way tanx before...
Last post made by: Karissap on Yesterday, 12:32 AM
