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MSP430FR6047: High noise level in USS design centre waveform for a clamp on water flow meter.

Antony Joshua
Prodigy 190 points
Part Number: MSP430FR6047


Hello Everyone,

I am trying to build a clamp on flow meter using MSP430FR6047 and Jiakang 1-MHz Transducer, I made a test setup as shown below. I am using a 50 mm pipe and set the parameters as shown below.

        

When I am pumping water through it at 500 L/H I get the following graphs.

Can some one please explain why my Delta TOF have negative values, also flow rate is having negative values in the graph. Is this normal or something wrong with my configuration? 

Also how can I display the real time flow rate in MSP LCD?

Please help, thanks in advance.

  • 0
    TI__Genius 12615 points

    Hi Antony,

    Do you see any change in the signals at higher flow rates? In order to see the results on the LCD, you need to build the project with the LCD ENABLED #define set.

    BR,
    Leo

  • 0 in reply to Leonardo Estevez
    Prodigy 190 points

    Yes, there is change in statistics but the signal is similar, lot of noise. When I increase the flow rate from 200L/H to 500 L/H the mean VFR changes.

    Can you please direct me to some LCD Enabled example project?

    Thanks and regards

    AJ  

  • 0 in reply to Antony Joshua
    TI__Genius 12615 points

    Hi Antony,

    The Water Demo project should have LCD enabled, you need to push one of the buttons to determine what gets displayed - I believe it's the down button.

    BR,
    Leo

  • 0 in reply to Leonardo Estevez
    Prodigy 190 points

    Thanks Leo, LCD is working fine now 

    Would you please take a look at my waveforms (Screen shot added earlier to this thread) and let me know if it is normal?

    Thanks and regards

    AJ

  • 0 in reply to Antony Joshua
    TI__Genius 12615 points

    Hi Antony,

    The ADC capture looks OK - although when using Jiakang clamp on transducers, the resonant frequency of the transducers will change slightly based on the contact interface(and ultrasonic couplant used). Can you run a frequency sweep between 900kHz and 1050kHz to better determine the best excitation frequency? Adjusting your excitation frequency to the system peak resonance should give you a better signal.  In addition, you might rotate your clamp on so that the transducers protrude horizontally from the pipe. Any bubbles that might be travelling around the top of the pipe can cause your signal to be noisy.

    BR,
    Leo

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