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  1. #1
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    loop powered level transmitter

    Hi,
    I'm designing a loop powered level transmitter which provides 0% for 4mA and 100% for 20mA.

    I have some idea about how to use the XTR116.

    But how to measure the capacitance and fed to micro-controller.

    Please help.

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  2. #2
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    Re: loop powered level transmitter

    Hi,

    What capacitance and what microcontroller.

    Please provide complete information, schematics, currents, voltages, measurement range and so an.

    Klaus



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  3. #3
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    Re: loop powered level transmitter

    For 470pf capacitance, instrument should provide 4mA.
    For 1470pf capacitance, instrument should provide 20mA

    Microcontroller: PIC18LF2520

    Since it is a loop powered, the instrument should operate below 4mA. As I'm going to use PIC18LF2520 with the operating voltage of 3.3V, So the current consumption will be 1.7mA max. I have to use remaining 2.3mA for the capacitance measuring circuit. But what IC should i use to measure the frequency?

    Please help.



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