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EVM430-FR6047: about ADC Capture

Wolf Bruce
Prodigy 180 points

Part Number: EVM430-FR6047

I can view the ADC Capture wave curve in the USS,is it fitting out by USS or the MCU?

Can I get the max amplitude of the wave,if can, how can I get it?

I tred to reduce the amplitude and fix the PGA gain,I found the TOF changed about 1us,Is that normal?

If the amplitude of upstream and downstream are different,what would happen? TOF would different? The water is  static.

Best Regards.

  • 0
    TI__Mastermind 46505 points
    Hi Wolf,

    The ADC capture is sent to the GUI from the MCU via the I2C interface.

    Can you provide some more detail about the max amplitude information you are looking for? Are you looking to have this display max amplitude over time or something similar?

    What is the number of ADC codes you are seeing? Ideally, you should adjust the gain to have about 800 codes.

    In theory, I do not think we would see a difference in TOF if the amplitudes are different, but the amplitudes should not be vastly different. Are you seeing a large difference in amplitude between UPS and DNS? At very high flow rates, there can be some difference in amplitude, but this is not expected at zero flow.
  • 0 in reply to Eddie LaCost
    Prodigy 180 points
    Hi,Eddie,
    Thanks a lot. I just want to get the max amplitude value of wave to know if it was disturbed by something (eg.bubbles),so I can deal it.
    In extreme cases, if one stream wave was disturbed by bubbles but another stream not,these two amplitudes maybe vastly different,so the Tof and DTof maybe wrong.

    Best Regards,
    Bruce
  • 0 in reply to Wolf Bruce
    TI__Mastermind 46505 points
    Hi Bruce,

    Thanks for the clarification. You could modify the application code to enable this.

    In USSLibGUIApp.c, after USS_startUltrasonicMeasurement(), you can add a function to search for the MAX & MIN of the captured signals, downstream & upstream. The captured waveforms are at gUssSWConfig, captureConfig, pCapturesBuffer. The memory buffer has the structure of sampleSize*numberOfAcquisitions * 2 as in the documentation for the USS SW Library. numberOfAcquisitions is usually 2, 1 for upstream & 1 for downstream. You can find the API documentation in the root directory of your USSLib installation. This is titled 'USSLib-ApiGuide.html".
  • 0 in reply to Eddie LaCost
    Prodigy 180 points
    Hi,Eddie
    Thank you very much!
    I 'll try it.

    Regards,
    Bruce

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