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MSP430F67771A: Polyphase Metering

Carlo
Expert 7715 points
Part Number: MSP430F67771A

Hi team,

Good day.

We received a query from our customer and we know that your expertise with the device can provide confirmation on these questions.

1) is the EMIC provided with firmware or do I need to write that myself? I found the available registers on: file:///C:/ti/msp/EnergyMeasurementDesignCenter_1.30.00.00/EnergyMeasurementDesignCenter/docs/users_guide/html/Energy_Measurement_Technology_Guide_html/markdown/ch_comm_protocol.html. But do not understand if its already on the bought chip and ready to use. Do you have a download link for the firmware on the chip? So I can already look at it?
2) Why is it necessary to measure the current on the neutral line? Or is it enough to have the neutral voltage as a reference to measure the power on a 3 phase 4 wire system? And what are the benefits if I measure the neutral line as wel?
3) Is it also possible to use it too for 3 measurements on 3 1phase systems?
4) Is it possible to get the current and voltage of all the harmonics? And if not, is there any EMIC in your collection that has this ability?

Thank you so much for your assistance.

Regards,
Carlo

  • 0
    TI__Mastermind 32870 points

    Hi Carlo,

    What is EMIC?

    The bought chip is empty, you need to program it. Normally, you can create the code by after setup your system in Emergy Measurement Design Center:

    Actually, you can't find the MSP430F67771A , you can refer to this FAQ: [FAQ] MSP-EM-DESIGN-CENTER: Why isn't my MSP430 part number listed?

    To measure power, you need to know the current and voltage.

    You can use it too for 3 measurements on 3 1phase systems. But you need to handle the software by yourself, because we only support to detect one system. Besides, MSP430 is not so powerful to handle three systems data.

    In the next generation, we will support current and voltage of all the harmonics. Maybe at the end of this year.

    Eason

  • 0 in reply to Eason Zhou
    TI__Expert 7715 points

    Hi Eason,

    Thank you very much for this information.


    For the EMIC, the customer is referring to Energy Meter IC.


    Regards,
    Carlo

  • 0 in reply to Carlo
    TI__Mastermind 32870 points

    Hi Carlo,

    As you have no further question, I will close this thread. If your customer is really need current and voltage of all the harmonics provided by TI, you can send me an e-mail.

    Eason

  • 0 in reply to Eason Zhou
    Prodigy 10 points

    Hi Eason,

    Carlo has send me a link to contact you directly. I have asked him a couple questions, but there is still one left that he couldnt answer:

    There are 4 current measurment inputs on the MSP430F67771A chip. Why is it necessary to measure the current on the neutral line? Or is it enough to have the neutral voltage as a reference to measure the power on a 3 phase 4 wire system? And what are the benefits if I measure the neutral line as wel?

    I mean is possible to measure the total power demand with only the voltage and current of each phase. Why would I need to measure the current of the neutral line? When the power demand in the system isn’t equally balanced, there will run current through the neutral line. But that can be calculated from the current measurements on the phases. Or is there any other reason? And if not, is it possible to use this chip (or maybe another is better suited for my situation) without the neutral current measurement?

    I’d like to hear from you!

    Regards, Thom

  • 0 in reply to Thom Steinfort
    TI__Mastermind 32870 points

    Hi,

    See from the designer center. You can only test the current.

    But see from the document EVM430-F6779(Three-phase Meter : Class 0.2 Accuracy), it test 4 current.  please give me some time to consult our expert about the difference. You can ask Carlo for my e-mail. 

    Eason

  • 0 in reply to Thom Steinfort
    TI__Mastermind 32870 points

    Hi Thom,

    Here is the reply from my colleague:

    EMDC can support measuring neutral current. For this, another current sensor can be added in EMDC to the seventh ADC channel of the F6779 device.

    Neutral current measuring (also called monitoring) allows you to detect tampering and can indicate unbalanced loads in the system. Ideally, no current should flow through the neutral connection if the loads are perfectly balanced. However, a small amount of current will probably flow in the real world. Higher amounts would flow when tampering has occurred.

    Hope it can help you.

    Eason

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