Re: Is it possible to add Event to the front of the Event queue?
Hello Jeremy I was thinking about state machine aswell, but I have already developped quite big application using events and I do not think I will go for state machine. Actually I think I may combine those two. Thanks anyways Pawel
Re: chart y axes overlap
Joe, Thanks for the tip but it doesn't work. The behaviour is different but still not correct. Jim/.
Instrument I/O Assistant on Target Machine error
The application reading serial port data and using the I/O Assistant works fine. The executable on the target machine gives a Visa timeout error. NI-VISA RTE has been installed on the target. Visa resource names have been used in the I/O Assistant.
Re: Alignment of front panel
Labview have a very good set of alignment tools. Normally you don't have to manually select each one, just click on open space and drag the mouse so that the rectangle covers all the controls (a group) you want to align, and then use the alignment tools. However, sometimes you still have to move the control a little bit to align them. Joe
Re: Notifiers vs occurences
Some pros for notifier that come to my mind : 1) Possibility to pass data. This is like a variable but without the need of polling -- no CPU usage while waiting. 2) They allow to wait for multiple notifications -- possible to synchronize more than 2 parts of independent code 3) A notifier can be cancelled easily. 4) It is not absolutely necessary to transmit the reference number of a notifier to the different parts of code. You can use its name. There is a description of notifiers in .\examples\general\notifier.llb\Notifier BASICS Part 1.vi If you only need to synchronize two independent parts of code, then occurences will do the job very well. But if you need more functionnality, then occurences are not the way to go.
Re: Programatically advance Scroll bar in Listbox
Thank you Joe Guo Works like a charm.
Re: Notifiers vs occurences
Thanks for a good answer. Few more things: Do occurences use CPU time by polling? If not then I think I can leave the code in the form it is now, and that is with occurences. I am using occurences to sync two pieces of code and thats all, no data passing etc. Comments?
Re: Notifiers vs occurences
CPU goes to sleep when waiting for an occurence -- same as for notification. No reason to change your code for that.
Why are shift registers are so slow
I am dealing with large amounts of data, arrays in excess of 65000x15. I need to build the array in a loop. When I use the shift register approach it takes forever. The fastest way I have found so far is to write the rows out to a spreadsheet file and read them back in. This is fairly quick, but seems rediculous to have to do. Memory should be much faster then a HD
Re: Notifiers vs occurences
Thanks a lot, for your help
Re: where can i find additional DDE resources???
HI again. As promised, I dug out my archives. Have a look at the (2) vi's attached. I used these as a client/server pair in a project 3 years ago, and they worked like a charm. I hope that I have documented the user inputs adequately to allow you to modify them to your needs. Good luck. Dave
Re: Set DAQ default file for DAQmx
Hi FrankyD, There is not a way to programatically switch between DAQmx configuration files. However if you need to switch between sets of DAQmx tasks, channels and scales only (not devices), an alternative is to programmatically create, configure, and manage these items yourself in LabVIEW. This is more work, but gives you more control. Let me know if this is the case and I can elaborate further.
Re: Matrox frame grabber LabVIEW
I also use ActiveMIL. I have found it better to turn off automatic allocation to all controls and programatically allocate them. This has the benefit of giving you greater control to troubleshoot and process errors or resets of the video system. I use allocate methods to allocate each control and the free methods to disallocate (free) them when an error occurs or a reset is issued. My systems are completely stable. I would recommend that you don=92t use grabcontinuous. Synchronize the video to your program by calling grabs as you need them. I typically have a video processing vi that runs independent of my test executor and all other vis and use notifiers to publish the video data of interest. I typically grab images at 60 msec rate with a 40% CPU usage on a 1 GHz processor. This gives me every other frame from the camera, fast enough for all my applications and leaves me 60% CPU for other procesing.
Re: Problem with converting levenberg marquardt fitting program from LV6.1 to LV7
Hello Ruud, I apologize for the delayed response. I am not aware of the curve fitting taking longer in LabVIEW 7. LV 7 is, however, threaded differently than LV 6.1. This may result in some differences. Another thing to consider is that the speed of the curve fitting is highly dependent on your initial guess coefficients. The more accurate they are, the faster the fitting will be. If you have further questions, let me know. Matthew C Applications Engineer National Instruments
Re: shift register only with unique data
Thanks Evan, just what i wanted
Open Access from Labview
Hi, I open a Access database with the metod Opencurrentdatabase of appliaction.But i had a problem because the database open but after it's closed. What's is the right method for call a database?
Re: how do i make a the black area of the graph transparent.
You need to use the paint tool and right click in the black area. A window should pop up to select the color. Choose the T in the upper right corner. This should make the black dissapear. You will then need to make the rectangle decoration of the waveform chart invisible too. It is done in a simmilar way.
Re: Controlling Khepera Robot 'Invalid page fault' errors using khepera gripper
I had no idea what you were talking about until I searched Google. The company K-Team manufactures the khepera robot. I recommend contacting K-Team to see if they have seen the same problem. You can attempt a reinstall of LabVIEW and possibly the OS if they have no information. If you would consider an upgrade too (LabVIEW is made better every release). Go to http://www.ni.com/labview/ and download the LabVIEW 7.0 evaluation. This way you can see if the problem persists.
Can I make larger SubVI Icons?
I have a SubVI with 18 input/outputs, and I am struggling to get all of the wires connected in a neat manner. Some of the stock SubVIs, such as Elapsed Time have larger icons to accommodate more terminals. Is there a way to do this with a custom SubVI?
Reference of the Bessel Jn(x) equation
What is the reference of the Bessel Jn(x) (theoretical) equation cited in the Help file? Where it was taken from?
test message, please ignore
this is a test message
Re: to import unique boundries onto an xy graph as a graphic
Hello Dancrilly, Thank you for contacting National Instruments. Would you post a screen shot of your XY Graph with the boundary pasted? If you could post the boundary and VI separately, that would be helpful as well. Sean C. Applications Engineer National Instruments
Re: test
Reply test
picture move in front panel
Dear all, I have a jpg picture. I need to write a program to make the picture move up down on the front panel. What function can I use for changing the location of the picture file on front panel? thanks
Numerous Start buttons in a while loop
I have a while loop, in which I inted to put many Start buttons, each of which relates to a different action. My problem is that once I click on the first button, it continues to run the first process continously. How do I make it stop after completing each sequence without necessarily stopping the entire program.
Utility VI for searching for the occurance of a string in all files in a directory
Is anyone aware of a utility VI that can search for a string(s) in all file types such as doc, xls, ppt etc in a specified directory?
Re: where can i find additional DDE resources???
looks like the attachments didn't make it
Using a sub-vi to write the strings of a ring inside a cluster on the main VI.
I have an array of ring controls in a cluster on my main VI. Now I want to use a Sub-VI to fill in the strings of the text ring from an array. I tried refnums and property nodes and to more specific class. I can access the ring array but whatever string I write in there doesn't show up. Can anybody please give me an example of how to do this? I am using LabVIEW 6.02 Thanks
Re: I need a Program or a Driver for the NV 40/1CL
Hello germannubie, Thank you for contacting National Instruments. I was not able to locate a driver for that instrument in our Instrument Driver Network (for any version of LabVIEW). You may want to contact your instrument manufacturer directly to determine if they have developed a LabVIEW driver. I would also suggest upgrading to the latest version of LabVIEW. Also, consider submitting a request for that driver at www.ni.com/idnet. Submitting a request does not guarantee that a driver will be made for that instrument, but if enough interest is shown, it will prompt development. You can always use the VISA functions in LabVIEW to communicate with your instrument. If you have further questions, let me know. Matthew C Applications Engineer National Instruments
Re: Numerous Start buttons in a while loop
Without seeing your code I will guess that your button's mechanical action is set to switch when pressed. It becomes true and stays true and your process always runs. Set the button to latch when pressed. The program will reset the button to false after it reads it as true. Your process will operate only once until you press the button again.
need hp4156a driver for labview 5.1
the version of the driver that is supplied with software has a bug in stop module I wonder if anyone knows the driver that is bug free. Labview has new drivers for
need hp4156a driver for labview 5.1
the version of the driver that is supplied with software has a bug in stop module I wonder if anyone knows the driver that is bug free. Labview has new drivers for 6.0 and higher versions but not for 5.1
Re: Not all of the provided ActiveX controls seem to work in...
Frances, With IMAQ Vision for LabVIEW 7.0 you can play An AVI file in the IMAQ image display. The read AVI example.vi does this. Austin Talley Applications Engineering National Instruments
Re: Grant/reject access to USB thumb drive
Hello Belur, LabVIEW is capable of modifying access rights to files using the VI on the controls palette found at File I/O Advanced File Functions Access Rights. The a href = http://sine.ni.com/apps/we/niepd_web_display.DISPLAY_EPD4?p_guid=B123AE0CBACD111EE034080020E74861p_node=DZ52027p_submitted=Np_rank=p_answer=p_source=External;Marking a File as Read-Only from LabVIEW/a example shows how to use this VI to modify file access rights. If you need more complex security functions, you will probably need to access third-party DLLs suited for your specific application. If this does not help, please post more information about the access controls that you are trying to implement, and which version of LabVIEW you are using. Have a good day, Kyle B. National Instruments
Re: Set data range of each element in array
Richard, Unfortunately, you can not change the properties for different elements in an array. An array is one set of properties with a bunch of different values. So the range of every element will be the same, however the values can obviously be different. Depending on your use case I would suggest using clusters. In a cluster each different control in the cluster can have different properties. Either that or take advantage of the =93In Range and Coerce=94 VI on the different elements of the array to check if they are in the range you wanted. Another method to get the desired results would be to use events to monitor what value the user is attempting to enter, and if it is out of the range for that element you could programmatically change it. Evan National Instruments
Re: Unable to access labview general zone from NI's website
Joe, I apologize for the inconvenience. We are experiencing some technical difficulties that are affecting the ability to browsing between the categories in the forums. You can still post, view, and search for postings. In addition your subscriptions should still work correctly. We are actively working to resolve the behavior, and apologize for any inconvenience or confusion this caused. Evan National Instruments
Re: Problem with linking dll.
Hello Ajit =96 The Call Library Function Node in LabVIEW does not require the input param to be defined for a program to execute. However, I will assume your program needs this parameter defined for your program to run as intended. For information on configuration of the Call Library Function Node, please review chapter two of the a href=3D=94http://www.ni.com/pdf/manuals/370109b.pdf=94Using External Code in LabVIEW/a manual. You can find an example in LabVIEW by navigating to HelpFind Examples. Choose the Search tab and enter and select the keyword dlls. The Call DLL.vi example allows you to browse examples of external code (C and C++) data types and how they interface with LabVIEW. This example is shipped with LabVIEW 7.0. If you are using a previous version of LabVIEW, please let me know and I can find an example that will work for you. If these suggestions do not solve your problem, please give me more detailed information about your application and how you would like LabVIEW to interact with it. Have a great day! Becky B. Applications Engineer National Instruments
Re: Can I make larger SubVI Icons?
Hi, A subVI allows having up to 28 terminals and sometimes becomes hadr to wire them. I LabVIEW 7 you have the option to view the subVIs as Icons or as large express format. You can change any subVI (native to LabVIEW or custom) to the express view by right clicking on it and disable the View ans icon function there you will be able to expand it to show the terminals. It would also be a good idea to group some terminals in clusters, tht way you reduce the number of terminals needed. Ihope this helps. Regards, Juan Carlos N.I.
Re: How can I synchronize a PCI-MIO-16E-4 with two 6602 cards?
Hi Sven, That's interesting. You might have to do a little more investigating to determine why the counters seem to start prematurely (or why the analog in is not reporting the scan backlog correctly). Are you using the startscan (scan clock) signal as the source of your counters? This signal will pulse as many times as you sample. One test you can perform is a finite acquisition with a specific number of samples. Your counter should count that exact number of samples. If the counter does in fact count the exact number of samples then we know your problem will be in monitoring the scan backlog of the analog input. Another thing that could contribute to the difference between the two backlog numbers is the fact that the analog input will store a certain number of samples in the onboard memory and then transfer them once the DMA FIFO is full. For the 16E-4 card, this FIFO size is 512 samples. This means that the card can accumulate up to 512 samples and then scan backlog would read 0. This is because the scan backlog monitors the samples on the PC buffer that you configured. The FIFO doesn't count in that scan backlog number. Only after samples have been transferred from the FIFO (MIO card memory) to the PC buffer (memory you declared in your program) will you see a correlation. Another way to easily monitor this is to use Interrupts as your transfer method instead of DMA. Interrupts will transfer each sample as it is acquired so your PC buffer will always be current (or off by no more than 1 sample). You can change this by using the Set DAQ Device Info function. Anyway, hope that clears things up. Have a good day. Ron
Re: How do I initialize a secondary axis with report generation vi's
Hello Mudda, It looks like you are trying to view two groups of data in the same graph, and then send that graph to a report. If your two columns of data are in separate arrays, you can use the =93Build Array=94 function to combine those arrays into a two-dimensional array (see =93Graph Waveform Arrays.vi=94 example, which can be found under Help Find Examples). A two-dimensional array can be wired directly into a graph. The two arrays will show up on the graph as different plots (in different colors), both on the y-axis. The data in the 10 range will show up lower than the data in the 100 range. If you want to plot your two data columns against each other on different axis, wire a two-dimensional array into an =93XY Graph=94 (see =93XY Graph.vi=94 example, which can be found under Help Find Examples). To view a graph in a report using a report generation VI, use the =93append front panel image to report=94 VI. The LabVIEW Report Generation Toolkit for Microsoft Office will provide more report functionality for adding graphs to Word and Excel, if you do not already have it. If these suggestions are not exactly what you are looking for, please post more information so I can better assist you; or, ideally, attach this portion of your application to examine. Have a great day! Robert M Applications Engineer National Instruments
Re: After reconfiguring a 6534 from output to burst input, I get error 10614.
Cancel it. The problem had nothing to do with turning the board around. It actually came from an earlier transfer using DIO Write and DIO Wait in which I did not explicitly specify to wait that the transfer was an output. John
Re: How to let the user define the colors for each plots in the graph (I use LabVIEW 7)?
Thanks Juan, it works. Have a nice weekend.
Re: Ignore first transmission from serial port
Hello Hema, Thank you for contacting National Instruments. This can be accomplished by using two reads back to back. Use the first read to extract the echo from the camera. Specify the number of bytes to read as the length (in bytes) of the echo information sent by the camera. Use the second read to extract the camera position. I hope this helps! If you have further questions, let me know! Matthew C Applications Engineer National Instruments
Re: Determining Voltage Rate of Change
The number of samples is irrelivent. The delta-T is derived from the sampling rate. In this case, 1000 HZ sample rate corresponds to 1 ms. delta-T. Good luck. Dave
Communication with AOL Instant Messenger
I would like to be able to use LabView to simply check the text sent through AOL Instant Messenger, and also to send certain text out, as if a user was on the computer. I would also like it to be able to control AIM functions such as send file. Is there a way to do that with LabView?
