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WEBENCH® Tools: Ultrasonic EVM / Transducer Selector math error?

Jarle Horneland
Prodigy 80 points

Tool/software: WEBENCH® Design Tools

Hello

I am looking into ultrasonic flow measurement, and encountered a possible error on your Ultrasonic EVM / Transducer Selector.
When trying co calculate TOF in the TI Ultrasonic EVM / Transducer Selector at: https://webench.ti.com/webench5/TDC/index.html?app=flowHead i suspect that the equations use the wrong  cos() function.
If I am to calculate the TOF with 45 degree placement I have to use the cos() in Radians and not Degrees to get the same result as the GUI. con(45)=sqrt(2)/2 = 0.707 and not cos(45)=0.525. A 46 degree angle would then give a negative delta TOF. As far as i can understand the cos() should be in degrees to work correctly. Is it correct that the error is within the GUI (the Ultrasonic EVM / Transducer Selector ), and you have implemented the wrong cos() function. Or is my calculations wrong?

regards Jarle Horneland

  • 0
    TI__Mastermind 41310 points

    Jarle,

    Thanks for your interest in the Ultrasonic Selector. After reviewing the information you provided and taking a look at the 45 degree calculations, a issue was found with the equation being used. The issue was not related to radians or degrees in the cosine function. The alpha calculation was not correct. The tool has been updated and should be working correctly now.

    Please note that the side by side calculations were not effected by this issue.

    Please let us know if you have any further questions.