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todd

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Everything posted by todd

  1. In a particular application I've got a few queues that fill up until the end of a test - then all data is dequeued. I wanted to add queue monitoring so a new loop gets all queued elements (from Get Queue Status) and displays as required. To keep the displayed data persistant, I use a shift register and 'filter from 1d array' to catch new values (see image). This was too dependent on timing. I use a single subvi to enqueue data from anywhere in the app. I changed the vi to put the data in two different queues instead of one. The second queue can dequeue data without affecting the persistant queue.
  2. With context help on, mouse over the waveform graph terminal on the block diagram. It directs you to search for "Waveform Graph.vi" in the examples.
  3. This has happened to me at least five times over the past year (undo - redo always fixed it). I reboot win2k every 4-6 weeks and restart LV every two weeks. I can not reproduce it but I think the problem gets cleared after a LV restart.
  4. In the past, Measurement Computing support consistently went out of their way to explain to me the workarounds for getting their hardware working in LabVIEW.
  5. I catch Event errors with the subvi in the attached image - even if the Stop button is not visible on the FP. For init, I still use one subvi before the While-Event loop. Usually, the init vi enqueues commands that are interpreted by queue handlers outside the Event-While loop. I agree it would be more convenient if there were First Run and Error events.
  6. I've placed a few express vis for convenience and out of curiosity. I ended up streamlining 1/3 of them and customizing another 1/3. Look inside and see (RMB -> "Open Front Panel", Convert).
  7. Since the input and output rates are both set to 8kS/s, I would assume they are synchronous. Some tests should show if the card has more than one sample clock and if they are coherent. This vi was built in haste. The first time I tried it, the output finished before the input started acquiring. The snake was to start the input acq before the output started. Notice the difference in X-axes (and Y-axes, for that matter).
  8. There's a windows version of expect from ActiveState. I don't know what it costs. Oh, from the buy page: commercial use for one user on any # of machines: US$295 education: US$49 free 21 day trial
  9. vi saved for 7.0 attached. The sound vi's did not convert to previous - you may need to replace them. Download File:post-107-1109035364.zip
  10. The obvious (therefore probably wrong) answer is "Number to Boolean Array". (At least my post count goes up "
  11. Ah, full duplex sound. I knew you'd soon reach the limits of my knowledge. A metacrawler search for "soundcard full duplex" turned up this page with this quote: However, on my work PC I was able to see the following image. I couldn't find a mic quickly so the signal may be crosstalk.
  12. Here is how to find an example that creates a sine wave in LabVIEW and sends it out through the sound card.
  13. If I recall correctly, the examples found by searching the NI Example Finder (under the Help menu) for "sound" were quite useful. The sound vi's are here:
  14. Yes. However, it is rare for me to have a BD much bigger than half of one screen. I usually keep the BD behind or near the FP and use one monitor for the main UI - the other for development of dynamic callees.
  15. This also works on Mozilla 1.7.3.
  16. Why not calculate all harmonics then index the arrays of amplitudes and frequencies?
  17. Here's some text from: ftp://ftp.ncsa.uiuc.edu/HDF/HDF5/contrib/labview/info FYI: We have finally released the applications which use HDF5. Included in the release is a set of LabVIEW VIs and a "glue" DLL to access the HDF5 DLLs. LabVIEW HDF5 users can get the HDF5 utilities by going to http://www.ni.com/ and typing "scope soft front panel" into the search box. Select the 1.5 version from the many hits resulting. Included in this self-extracting ZIP file is another self-extracting ZIP file titled sfpFile.exe. This contains the LabVIEW VIs to read and write the HDF5 based waveform files used by the soft front panel. Documentation is included for the higher level VIs. Users only interested in the lower level VIs will find they match the HDF5 C API very closely. The set of VIs is not complete, but they handle most common functionality. They can easily be used as templates to generate additional functions. Requests for additional features can be directed to info@ni.com. The contact people are Norma Dorst and Lokesh Duraiappah. If the user wants fast response, mention at least one of them in the e-mail to ensure proper routing. Support is through the usual NI routes. I found 2.5 here but it's still downloading (39MB) so I have not yet checked it for sfpFile.exe. [edit] So now I see that Michael provided the link to sfpFile.exe. [/edit]
  18. I found them by searching the Functions palette for "gaussian", "auto power" and "harmonic". I am using the PDS, however (e.g. add-on toolsets), and it seems like the toolset used to be listed in the search results. Is there a simple way to tell which vi's are part of a toolset? Perhaps just knowing which top-level function palette is enough.
  19. I have not worked with those data formats. I am interested in what you learn. Here's some expounding: The only reason I can think of not to use a relational database is the metadata. I've used a few methods of storing metadata. The attached gif shows metadata in the filename. I've also used ini files with sections for parameters and for data. These are saved as csv so excel will associate (for my colleagues). The work I've done with databases has been focused on creating tools that make new databases based on the swept parameters. Of course, there is another tool that creates viewers of each database. It's all very clunky and makes intra-database correlations difficult.
  20. Search these forums for "SQL".
  21. How about this. From left to right: "Gaussian White Noise.vi", "Auto Power Spectrum.vi" and "Harmonic Analyzer.vi"
  22. I haven't seen any trouble yet.
  23. Yes to both: using the nVidia desktop manager, or whatever it's called.
  24. I thought you were looking for gaussian noise. If that had been true, the number of samples for "Gaussian White Noise.vi" could be set to the number of samples in your data set before adding. My mistake.
  25. I wonder if you have access to "Gaussian White Noise.vi".
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