Problem with Framing and the DLL

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13 Oct 2010
Posts:

Hello,

I'm having issues with the framing feature of the Cscope Control Driver DLL and I hope posting here will help find a solution.

I need to sample X number of events with the digital trigger set to a certain pattern and upon a rising edge from the external trigger input. I need to do this an arbitrary number of times, then retrieve the data. Essentially, the data should be X samples per frame with the number of frames being the number of external triggers that occurred.

With the Cleverscope software this operation works perfectly. We setup the number of frames and frames per capture to 1200 and 1199 respectively. We start the acquisition, run the machine, select SEQ, and Get Frame. All the frames are loaded back-to-back, we save the data, and it all looks great.

I'm trying to duplicate this functionality in a LabWindows/CVI program utilizing the Cscope Control Driver DLL. I've setup everything to the best of my ability, given the documentation and what little I've found on this forum. TransferSize = 6, NumSeqFrames = 1199, NumBuffers = 1200, etc.

I adapted the LW sample into my app. Regardless of what I do to setup the framing, the timer loop still works as expected and the framing does not. The first frame is always returned during the check_for_samples() function. As per the documentation, once I see a sample come back from the c_check command, I call the call_cscope_control_driver function with a c_get_frames command. After this, I again issue another c_check and nothing ever returns. If I reset the acquisition it will again return one frame, then hang.

During any of these calls to CscopeControlDriver, the frames returned parameter is always 0. I've played with the start/end times, number of samples required, number of buffers, number of frames, frame number, etc, with no luck and no apparent change in the original behavior, just no framing.

Any idea what am I doing wrong? I would love to see the LW example adapted to work with framing, it would be the easiest to see what is going on here. I've been pulling my hair out for a couple of days on this, and it needs to work soon, before the project gets derailed because of it.


Thanks,
Kyle

14 Oct 2010
Posts: 395

Hello Kyle, We have extensively tested multiple frame transfer under the Labview driver vi, and using Microsoft Visual Studio, Delphi and C Builder using the DLL. However, we have probably been a bit remiss - there have been some quite significant changes and I'm not sure the Labwindows environment has kept pace. We will check, and report back.

23 Oct 2010
Posts:

Just wondering if you were able to check into this issue yet? My client is getting anxious for his software to work... :)

24 Oct 2010
Posts: 395

Hello Kyle,
We did get your email, but were holding off until we had written an example for you to test with. This has been done and is now in our 'Resources' section (see http://www.cleverscope.com/resources/). It conforms to the description given for the Labview 'Sequential Capture' example documented in 'Cscope Control driver vi description'. The download includes a built executable for you to try. The download is called 'Labwindows Sequential Scope'. Good luck with it.
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