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Tim_S

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Everything posted by Tim_S

  1. We buy our industrial computers (which are rack mount) from Advantech for the moment. We're typically getting 12 PCI slots and 2 ISA (yes, we still use an ISA card ). We've had mixed results; typically the negative results are due to 1) customer requirements for a performance machine from an industrial computer, 2) standard industral computer issues (e.g., the PCI bridge fried), 3) repairing the warantied PC involves shipping it to California for two weeks, and 4) the local sales rep stopped returning our calls and was mysteriously replaced. The positives are that the local rep was replaced, the systems tend to just work out of the box and they last decades so long as typical PC maintenance is done. The other outfits we've had drop by for lunch-and-learn sessions have seemed about the same. There was one in Ann Arbor, MI (sorry, I can't recall the name) that talked a good presentation and had some good "street cred" to back it up. We've not used their systems yet. Tim
  2. That takes me back to my undergrad thesis. We had to document that, even though all they needed was a PC, a PLC was also needed on the shipboard test system so that the Captain didn't turn off the six-month test the first time the system gurgled. Tim
  3. Who are they? I think I have some ISA VGA cards and 2400 baud modems at home I'd like to sell them. I was able to locate 10M and 100M but no 1Gbit. I recommend, should you find such a device, that you start looking for 4-leaf clovers and playing the lottery. Tim
  4. Tim_S

    DC Motor

    wincraze83 - You're not giving a lot to help you with. You'll need a servo driver and that will be controlled by some digital I/O or comm I/O depending on the driver. The driver may have seperate enable lines and interface with an E-Stop circuit, or it may be a "dumb device" with no safety circuits built in. You may be able to connect TTL level signals to it, you might not. There may be an analog output for speed feedback, there may be an encoder, and there may be nothing so you have to add a speed pickup. You're going to need to research and make some design decisions based on what you are doing with this motor. Tim
  5. Tim_S

    DC Motor

    You don't mention what hardware you have nor what type of DC motor (stepper? permanent magnet? servo?). Tim
  6. I'm curious why you're using this method rather than using the DAQmx Flatten Channel String VI? Tim
  7. Any motor and driver can generate a lot of electrical noise that can fry elctronics connected to them. I think sachsm is right about optoisolation. The PWM controller may have sufficient isolation on its own; it should be OK if it accepts TTL inputs, though a little paranoia is not a bad thing. Otherwise, you'll want to be careful of your grounds, EMI and routing of cables. I've seen 12V solenoids create electrical noise on shielded twisted pair analog inputs when switching the solenoid. Tim
  8. I notice from your sig that you're an undergraduate. I take it this is a project for a class? I'm not too familiar with the image processing toolkits. Have you gone through the pallets and checked out the help? Tim
  9. Is there a reason you're not using C++ to read the TCP message? I think we might be able to assist you better if you can post what you've done in your DLL. You could send a timestamp with the request, however you'd have to synchonize the clocks at the client and server. Tim
  10. Extend your time sample if you are just looking to increase the df (df ~ 1/T where T is the time length). You may want to look at a Zoom FFT in the Sound & Vibraion Measurement Suite if you are only looking at a small portion of the frequency range. Tim
  11. Can't have too many chickens about. Can't say I have had good luck with memory deallocation either, but the times I have tried it I wound up redesigning chunks because what I was doing required going back and checking my sanity. As a thought, that is a lot of data to display and can't have everything visible on a graph. Can you read in from file and decimate to something somewhat sane? This may be quite slow, but trying to keep everything xN copies in memory would also slow the machine down. Tim
  12. Ah, the evilness that is copies of data. Have you... - Reduced the number of subVIs - Tried using Request Deallocation - (LV2009) tried passing by-reference data - Attempted to use smaller chunks at once - waved the dead chicken Tim
  13. One day we will have robots following us about to inject happy drugs. Sorry, been reading too much Sluggy Freelance lately... Curious... what are you doing that you need 2GB chunk at once? Not that I haven't had Windows take down LV for exceeding 2GB... Tim
  14. I agree with asbo... Your best bet would be to open a source and create a target file as binary and to read/write out chunks, updating a progress bar every N-th itteration of your loop. There is a JKI progress bar (I believe it's in the Code Repository) that may help you out with that portion. Three minutes with the user wondering if the program is locked. My experience is users do not have much patience and have a tendency to kill programs that they think aren't responding.
  15. Tim_S

    SCPI commands

    I consider it good practice to open the VISA connection and then clear out any "garbage" that may be sitting in the buffer. I don't see how it'd be necessary before closing a connection. Tim
  16. I missed the difference in number; I thought that USB 6220 was typed instead of 6210. Drat, that little difference could be huge. Tim
  17. Tim_S

    SCPI commands

    A block diagram is always better when asking questions. The issue may be on the end of the o-scope; I expect you'll need to call their technical support. Tim
  18. I did a bit of poking about and discovered two articles: http://forums.ni.com/ni/board/message?board.id=170&message.id=123821 http://newsgroups.derkeiler.com/Archive/Comp/comp.lang.labview/2008-02/msg00510.html I tried the 'UseUnicode=TRUE' with Chinese characters and that seems to have worked. Labels don't seem to take unicode, but button text and string text seem to accept them. Tim
  19. LabVIEW doesn't support unicode characters, but does support wide characters. I've not been able to get wide characters to display Chinese yet, so I'd like to know if you manage to get Greek characters to display. There are some third party controls that can be dropped into LabVIEW that can add unicode support; appologies that I don't have a link at the moment to point you to them. Tim
  20. Same answer as with numeric data types. Tim
  21. Try putting an array into the comparison. The output will switch between a single boolean and an array of booleans as you switch between comparing elements and agregates. Tim
  22. The wording of your questions is a little confusing. If you mean you want to know if you can take a PCI board and make it a USB board, then it is possible, but you'd be far, far better off just buying the USB variant as you'd be developing your own PCI to USB bridge and software drivers. If you mean changing the software to use a USB-6220 instead of a PCI-6220, then that's a mere matter of switching the physical channel you're measuring in your software. Tim
  23. The example works, however there is a constant on the block diagram for the register address. You may also need to switch betwen input and holding registers. Appologies that I can't be more helpful right now. Tim
  24. A lookup table works well for multiple-language support. My company has used them for LabVIEW and non-LabVIEW programs. The difficulties you can get into are in attempting to reuse messages for the same type of error (e.g., file not found) and ensuring there is sufficient space for the text for all languages. You've not mentioned Chinese or Russian, so unicode characters shouldn't be a concern. Tim
  25. wishes he wasn't the on at the bottom of the hill.

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