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EVM430-FR6043: Gas Meter Component and Device Selection

Kripa Venkat
Expert 5365 points
Part Number: EVM430-FR6043


Hi,

I have just bought the EVM from TI, EVM430-FR6043 for my gas meter applications. I am in the process of selecting the right ultrasonic sensor, but I have some questions

1. For my application who do you recommend as a transducer manufacturer?

2. What voltage levels are subjected to the transducer when connected to the EVM?  

3. What are the basic requirements for voltage level in terms of driving the transducer and receiving signals back without saturation. Essentially, what is the maximum voltage allowable to excite transducers and what is the maximum

4. I see there is an external Op-Amp, why would I need it if there is already gain available on the chip?

Thank you

  • 0
    TI__Genius 12615 points

    Hi Kripa,

    Please see responses below:

    1. If you are looking for a catalog(non-custom) solution, I would recommend that you evaluate Audiowell and Jiakang transducers.  If you are willing to invest in a custom solution which could provide better accuracy, I would recommend that you evaluate Ceramtec transducers.

    2. The transducer will be excited with 3.3V when the EVM is powered from USB. The MSP430 is rated to operate up to 3.6V so an external 3.6V supply can also be connected to drive the transducers(and the EVM) at 3.6V.

    3. The amount of excitation voltage required is specific to the distance over which the ultrasonic signal must travel and the attenuation of the medium.  Your signal can also be attenuated by design elements in your ultrasonic channel.  The trade-offs in using a lower excitation voltage are primarily with respect to the standard deviation of your measurements.  Higher excitation voltages can give better standard deviations at the expense of power consumption. The maximum excitation voltage allowable by the EVM via the transducer excitation circuit is 5.5V.  (A separate voltage supply of 3.6V(or less) should be applied to the MSP430.)

    4. Ultrasonic signals can be heavily attenuated in methane(requiring more than 60dB of gain in some cases).  The integrated amplifier provides up to 30dB of programmable gain.  The external op amp circuit can provide the additional gain required by your specific application.

    BR,
    Leo

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