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DredPirate

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About DredPirate

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  1. I am feading a constant complex double (CDB) set to -9+0i into the square root function and displaying the result.
  2. And here is another reason not to use express VIs or LV unit labels. Had to kill LV to stop this VI.
  3. Maybe I'm missing something but I do not beleive LV does the math correctly for complex numbers. Isn't the square root of -9 = to 0+3i? If so why does LV give a result of -8.13152E-20 +3 i? It's close but not correct.
  4. There are 2 items I don't agree with in this presentation. 1. Backround Color. I find it more readable to set the Block Diagram color to a light manila. 2. Error handling. I that LV does a terrible job of Error Handling. To often have I seen LV lock up code with a popup when it recieves an error. If you're not extremely careful you could loss data or worse destroy equipment. Other then that I think thats a great guidline on how to code in LV.
  5. You could also use a local variables or functional (LV2 Style) globals to pass your data within a case structure to your loops. That way you wouldn't need to send a variable out. And would more closely resemble you line baised equvilant.
  6. First, do not use global variables. They make maintenance and debugging a nightmare. Not to mention they are terrible on resources. If you have to use globals then look up LV2 style globals. If your program is structured correctly you should not need them except for a few special cases. Which brings me to number 2. Your main issue seems to be program structure (or lack of). Look up state machines. This is the best way to program in LV. Also make sure your file structure is well defined (do not use LLBs. They strip the file structure and offer nothing in return but bugs. There is a
  7. Fist let me say that I solved this puzzle in about an hour. Great program! Lots of fun. You didn't need to impliment a way to clear mistake LV did it for you. Just right click and re-initialize to default it will clear the element you select. Although it doesn't work on the house color.
  8. First let me make some assumtions. It sounds like your doing a simple Back EMF measurement. Your speed control is probably +/-1 RPM. Your using a Brushless Servo motor for your drive. Your diving a Brush type motor. This is for a piece of development equipment (not production or lab). And you have no budget foir this project. Now unless your servo drive provides some sort of velocity feedback you will be stuck buying something. So lets find the cheapest and easiest solution. Seeing as your a newby to LV we will want something simple to measure. Doing a dynamic signal analysis to extract the
  9. You could throw an AB quad encoder on the motor and use a PCI-6602 counter timer to monitor the position output. Then do some math and you get RPM. Or put the encoder output into a frequency to voltage converter and monitor it on the PCI-6221. Or set up the PCI-6602 to monitor frequency off of the encoder. Or set up a curcuit to capture commutator pulses. Or measure the com pulses with the PCI-6221. Or measure the voltage and current and compare that to a performace curve. Or ................. The list goes on and on. The method you choose really depends on your aplication.
  10. First The software is set up to take 4 readings at a time from a standard NI Multifunction DAQ card. To change the number of channels you need to edit the AI Config:physical channels constant on the left side of the screen. Look up Physical Channel Naming Convention in the help menu. I was taught an LV programmer with like 10+ years expereince so I never had to go through the pains of learning on my own. There were some things that helped though. 1. Take a LV training course if you can afford it. Although I do not agree with alot of the practices they teach, it will help get you familiar w
  11. Not true for multicolumn listbox. You can set the selection color. See the attached VI. Download File:post-3219-1131731871.vi
  12. No. It seems to work fine. The only undefined string I get is the empty string and only after I delete everything from the combo box. BTW I am using LV7.1.1
  13. First, look up state machines. This is the method of programing used by all LV programmers with any experience. Next I don't know if this is what you're looking for but I created a quick example of what I think you're looking for. Check it out. Download File:post-3219-1130797095.zip
  14. Same here. Dell monitors seem to like 1280X1024. Although, I do use the space. Every computer in or lab is a Dell (they were bought before I arrived) so I don't see a need to reduce the space to 1024X768 for anything but posting. (Sorry for the earlier post at 1280X1024. I will reduce the size in the future). BTW best computer supplier I found for test equipment is Axiom. Industrial Single Board Computer (SBC) with up to 14 PCI slots and resonable price. Never used more than 6 PCI slots but its nice to know its there is I need it. Its really nice when you have one at your desk. You just l
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