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MSP430FR6043: The parameter changes of the 6043 evaluation version are applicable to different gas meters.

Tommy
Intellectual 515 points
Part Number: MSP430FR6043


Tool/software:

hi,E2E:

Regarding the evaluation version, before porting to the 5043, I have several questions:
1. If the distance between my transducers is not the same as in the example routine, which parameters do I need to modify?
2. Does the Volume Flow Rate Scale Factor also need to be modified? How should it be adjusted?
3. What are the units of the parameters in USS_Algorithms_Results_fixed_point?

  • 0
    TI__Mastermind 46765 points

    Hi,

    1. It usually requires to change the gap between pulse start and ADC capture accordingly when the distance between transducers changes. 

    2. USS_VOLUME_SCALE_FACTOR is also known as the meter constant. It will need to recalculate its value when there are changes on the pipe design. Just follow how you calculate the meter constant value on the first place. 

    3. For TOF result the units are seconds, the data format is saved as iq31 and iq44. You may need to convert this format to float for an intuitive result.

    For migrating to FR5043 please refer to this app note. https://www.ti.com/lit/pdf/slaaes9 

    Best regards,

    Cash Hao

  • 0 in reply to Cash Hao11
    Intellectual 515 points

    Thank you for your reply, but I find it a bit unclear.
    1. Is the parameter `#define USS_ACOUSTIC_LENGTH 70` the one that needs to be changed when modifying the distance between transducers?
    2. Could you provide the calculation formula for this factor?
    3. Regarding the struct `USS_Algorithms_Results_fixed_point` below, I would like to know the units of each parameter inside it:
    typedef struct _USS_Algorithms_Results_fixed_point_
    {
    USS_message_code messageCode;
    int32_t iq44DeltaTOF; //!< Delta Time Of Flight calculation result
    int32_t iq40TotalTOF_UPS; //!< Upstream total Time Of Flight calculation result
    int32_t iq40TotalTOF_DNS; //!< Downstream total Time Of Flight calculation result
    int32_t iq16VolumeFlowRate; //!< Volume flow rate calculation result
    int32_t iq16VolumeFlowRateNoCalib; //!< Volume flow rate calculation result without VFR calibration (only used for VFR calibration)
    int32_t iq16Temperature; //!< Temperature calculation result
    } USS_Algorithms_Results_fixed_point;

  • 0 in reply to Tommy
    TI__Mastermind 46765 points

    Hi,

    1. You can ignore the USS_ACOUSTIC_LENGTH. It is not used in the algorithm. 

    2. VFR = Meter Constant * dTOF / (absTOF_UPS * absTOF_DNS). The VFR is getting from a reference meter, and the TOF results are getting from the USS library. Then you can get the Meter constant value based on this equation. 

    3. The TOFs unit are all second. The difference is on the data format. The dTOF is in IQ44 format. And absTOF is in IQ40 format. Use IQ44 format for example. If the dTOF shows in IQ44 format 0x34a5d79, you first convert this hex to decimal 55,205,241. Then divided it by 2^44. So, the result will be 55,205,241/2^44 ~= 3.138*10^-6 = 3.138 us. 

    Best regards,

    Cash Hao

  • 0 in reply to Cash Hao11
    Intellectual 515 points

    Hi,

    Okay, thank you for your reply. I have one last question:
    If the pipe cross-sectional area changes, which parameter do I need to modify?

  • 0 in reply to Tommy
    TI__Mastermind 46765 points

    Hi,

    Directly change the Meter constant value, any change on the hardware will reflect in the Meter constant value. 

    Best regards,

    Cash Hao

  • 0 in reply to Cash Hao11
    Intellectual 515 points

    ok!thank you !

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