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TIDM-THREEPHASEMETER-F6779

Ahmed Hafeez
Prodigy 20 points
Other Parts Discussed in Thread: MSP430F6779

Hi, 

We are evaluating the EVM430-6779 Energy meter for measurement and testing. The product datasheet mention input of 230-V input voltage. we wanted to find out Is there any safe guards if the voltage is higher than 230-V.

In future we are looking test this in different environments Will this be possible?

Thanks 

Ahmed 

  • 0
    TI__Mastermind 49692 points
    Hello,

    Thank you for your post. If you want to use inputs higher than 230Vrms, you'll want to reduce the resistance of the lower resistor in the voltage divider (keep the upper 990kOhms) accordingly. Keep in mind that the input voltages are typically in RMS units and need converted (multiply by sqrt(2))to peak values to match the units in the datasheet. Ideally, you want the maximum voltage channel input voltage to be close (but not more than) to the max Full-Scale Range (FSR) at a Gain of 1. Do this by adjusting the resistance mentioned above according to your max input voltage.

    What do you mean by "different environments"?

    Regards,

    James

    MSP Customer Applications
  • 0 in reply to James Evans
    Hello James,

    Thanks for your response.

    Firstly myself and Ahmed are working together on this. We are not very technical. The reason we have purchased this EVM is so that we can test its accuracy and workings. We are based in UK where voltage can range from 220v - 250v. This is the reason behind our query.

    Will the high voltage actually damage the circuit or it will just give wrong readings. i.e. is this dependency on software or hardware or both.

    I also understand that there is a clip (near the current input) that engages voltage input. if we disconnect that clip presumably device will be ok under high voltage.

    This 230v max is quite limiting especially out side of US. Any help will be much appreciated.

    Regards
    Bilal
  • 0 in reply to Bilal Mukhtar Ahmad
    TI__Mastermind 49692 points
    Hello,

    At 250Vrms, you'll be fine. Using the calculation described above, the peak output voltage (converted from RMS) from the voltage divider going to the ADC channel is equal to 844mV. For the MSP430F6779, the max FSR at a gain of 1 is equal to 930mV. Thus, the EVM should work fine at 250Vrms input voltage.

    Also, I’m happy to inform you that the official software release for the new Energy Measurement Design Center and Software Library is available on TI.com. It supports CCS and includes documentation and Design Center examples for the supported EVMs. Please download and install the release from the following link:

    www.ti.com/.../MSP430-ENERGY-MEASUREMENT

    Let me know if you have any questions.

    Regards,

    James

    MSP Customer Applications