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    Voltage reading is not constant from DAQ

    I have the NI6259 and want to read an analog signal.

    I connect DC voltage 0.35V to the AI0 analog input pin of NI6259 through a BNC connector. The ground pin of the signal generator is connected to the ground pin of the BNC adapter.


    The measured signal is oscillating. Could anyone help to explain? It should be a constant voltage. Thank you.


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    Re: Voltage reading is not constant from DAQ

    Hi,

    obviously 60Hz mains frequency.

    Loop via Earth_GND?

    Your pictures and description donīt give much information. Itīs just a snippet of all the devices and connections involved

    For example: where is the "0.35V" coming from and where itīs power is coming from, what cbles, what length and how they are installed.....

    Klaus
    Please donīt contact me via PM, because there is no time to respond to them. No friend requests. Thank you.


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    Re: Voltage reading is not constant from DAQ

    Thanks you. When I connects it with the differential mode, when there is no ripple.



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    Re: Voltage reading is not constant from DAQ

    Quote Originally Posted by shanmei View Post
    When I connects it with the differential mode, when there is no ripple.
    Then why not run it in the differential mode.
    Please give us more info on what you are doing, so we can avoid a game of 20 questions.
    Zapper
    Curmudgeon Elektroniker


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  5. #5
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    Re: Voltage reading is not constant from DAQ

    In the DAQ software setup, I set the terminal configuration to be " differential", then the measured signal is stable without the ripple.

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