Jump to content


  • Posts

  • Joined

  • Last visited

  • Days Won


Everything posted by bbean

  1. hoovahh I implemented the same operation as your subvi and it did not appear to work when I looked at the generated code. So I went back and created some debugging code to get the block diagram image before and after cleanup to compare to the final code: The result of probing these images is that it appears block diagram cleanup occurs but then gets lost: Before BD.Cleanup: After BD.Cleanup (just what I want): Final "Generated Code" (somewhat crapified) The only other thing that happens after the Generate Code Ability VI is that I do an "Update Image" (calls the Image Ability). Could this cause the diagram to get screwed up?
  2. Rookie question here. I'm getting lazy and don't want to click the cleanup diagram button when I'm debugging generated code in the Xnode. Is there a way to clean-up the Xnode diagram with scripting? I tried putting some cleanup commands on the diagram reference in generate code ability, but I'm guessing the code is not actually generated until after this VI is completed. Or maybe I'm doing something wrong. Is there another ability that can run after the code is actually generated where I can cleanup the diagram for debugging purposes?
  3. You can still have a producer/consumer loop if you want. The nice thing about Hoovah's circular buffer is that its DVR based so you could spit the wire and read the data in parallel if you want. I haven't seen your code and do not know how you want to trigger the save data. Do you need to analyze the whole buffer every iteration to determine whether to save or are you doing something like just triggering on a rising edge level and only need to look at each daq read chunk? You can probably do all the DAQ reading/triggering/saving in a single loop if you use pipe lining. But I can only speculate unless you attach code. A crude example using the Circular Buffer Demo.vi as a starting point:
  4. Use no delay and this Circular Buffer: https://lavag.org/files/file/250-circular-buffer/
  5. Very impressed with the simplicity and elegance of that timer solution. <possible thread hijack> Along the same lines....do you guys ever use the DAQ Events functionality within the JKI state machine in the same manner? eg using the DAQmx events along with a daqmx read in the event structure similar to LabVIEW example: \examples\DAQmx\Analog Input\Voltage (with Events) - Continuous Input.vi Or are the downsides to reading daq at high speed in an event loop outweigh the potential benefits?
  6. The event structure is in a parallel loop (just like your consumer loops) with a branch of the VISA session going to it after your initialize. The event loop will be waiting for an event (in this case the stop button press). When you press the stop button it will fire an event , in that event you would execute the VI I attached which should kill the VISA session, which will cause an error in the Read VI (unlocking it) in your loop where you currently have the stop button control wired up.
  7. Not sure this will work, but try using the attached VI in a parallel while loop with an event structure and event case for stop button value change. Its just a wrapper around the viTerminate function in VISA. Also put a sequence structure around the current stop indicator and wire the error wire from just above to the new sequence structure to enforce dataflow to the stop button. This way it will read the correct value after the event structure fires. Not sure why you would do this but if its your preference then go ahead. As you can see its causing you problems Don't waste your time. VISA Abort Pending Calls.vi
  8. The last time I did data acquisition that required start triggering (ai/StartTrigger) was 5 years ago in a LV8.6 application. I seem to remember that the dataflow would pause at the slave's DAQmx Start Task.vi until the master arrived at its DAQmx Start Task.vi, then each task would proceed to their DAQmx Read VIs. Fast forward to LV2014 where I'm trying to help someone on another project get DAQmx start triggering working. In LV2014, the process appears to operate differently and the slave's DAQmx Start Task.vi executes without pause and continues to the DAQmx Read.vi where it doesn't return data until the master AI input starts. Did something change or am I growing old and developing dementia?
  9. Recently I was having massive slowdowns opening VIs, including classed, but the culprit turned out to be an old link to an SCC Perforce Server that was not valid. Not sure if that is your problem or not, but if you have source control enabled in labview, you could check that.
  10. What if you decrease the frequency of the 0x00 eg. have a 1ms wait between each 0x00 send and use a while loop that exits after 1 second of elapsed time (vs a for loop).
  11. I can't really tell from the NItrace or code. Do you have the manual that describes the wakeup protocol that you could also attach? Is the touch panel a "real" serial port or a USB to serial converter? One problem I've had in the past with USB comm (or USB->serial com) was with the OS sending the USB ports to sleep. Not sure if it could/would be able to do this on a "real" COM port. Check the Advanced Power Settings in Control Panel\All Control Panel Items\Power Options\Edit Plan Settings and disable this everywhere. You may also have to disable something in the BIOS. The worst part about the USB sleep feature is that the more efficient you make your program the more likely the OS is to power down the USB port.
  12. Can you attach your 2009/2012 VIs and NI IO Trace logs?
  13. As a work around, what if you open with Option set to x100? it seems to release memory then. I don't know if its bad form or opens another can of worms to open with "Prepare to call and collect" but never collect. The documentation seems to indicate so. Quote: If you use this option flag (x100), you must include one Wait On Asynchronous Call node for every call that you begin with a Start Asynchronous Call node to ensure that LabVIEW does not retain any started calls in memory indefinitely.
  14. Obviously this depends on the circumstances, but what mechanism do you use to execute the "do" portion of code that could hold up the event structure? Do you just pipe information into a parallel queued state machine or actor? Is there a post on lavag or on the darkside that lays out the benefits or pros and cons of this (using user events) vs just directly piping the "do" into a separate parallel queued state machine queue?
  15. Do all your loops with CAN communication have a Wait ms in them? Maybe CAN performance got better and the PC doesn't have time to sleep.
  16. What type of performance hit would you expect manipulating pixels using IMAQ ImageToEDVR and an IPE? Curious as to the difference between an algorithm implemented with this technique vs a c DLL call, but I'm not near a development environment with Vision.
  17. Are the Matrox dll calls thread safe? Are you making any dll calls in your image processing? Is it possible they are executing in the user interface thread?
  18. Off topic: that looks like one of the most interesting/promising improvements to the Vision toolkit in a while.
  19. CharlesB...I can't figure out where your race condition is. Also am not sure why you need all the extra mechanisms (Semaphore, DVR, Status) when you can achieve the same thing using 2 simple queues as shown in my example. Plus the 2 queue approach guarantees you can not work on the image being displayed until it is put back in the camera/processing pipeline. IMHO it is a simpler and easier to debug solution. The other thing my solution does is allow you to do the image processing in "parallel" to your acquisition.
  20. ShaunR - I was unaware that you could use events like that with Imaq IO refs...very nice. I will have to remember that for my next vision app. While the Godwin Global approach is nice, I think there are two issues: 1) I believe the poster is not using IMAQ camera interface (Matrox proprietary instead) and 2) Somehow his Imaq Image Display is getting corrupted by newer images when it is updated faster (400fps) than it can be painted by the OS. I'm not suggesting the "triple buffering" approach is the proper solution here, but I am collaborating with the hopes that he can see a "simple" LabVIEW queue approach can work. PS. I surprised ShaunR doesn't have a "Cantankerous Callback" approach and I haven't seen any Actor Framefork approaches with multiple Actors.
  21. Triple Buffering with simple queues and shift register. BufferTest.llb
  22. Is the attached closer to what you want? it prevents the "corruption" of the imaq image ref by taking it out of the cam /processing buffer while it is being displayed. The third image reference in the VI is pretty much worthless. But wanted to see if this was a step closer. BufferTest.llb
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.