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Analog to 1-Bit Digital Signal at a Threshold

Discussion in 'General Electronics Discussion' started by SmackoJones, Jul 26, 2017.

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  1. SmackoJones

    SmackoJones

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    Jul 26, 2017
    Hello!

    I am looking to convert an analog signal to a digital signal so I can use the digital triggering function of my NI DAQ (I know some DAQs have analog triggering capabilities but I cannot afford a new fancy DAQ). I would like the digital signal to be low when the analog signal is below 2V (or any threshold) and the digital signal to be high when the analog is 2V or above.

    I was thinking I would use an op-amp comparator circuit with a diode before the voltage output to achieve this but I am concerned about how the NI DAQ digital input port will receive this voltage output (especially the linear region if it is not steep enough). I got the idea from this site:

    http://www.electronics-tutorials.ws/opamp/op-amp-comparator.html

    Can an analog signal into a digital triggering port damage the DAQ? Will this method work for my application? Is there a better way of achieving my goal?

    Thanks!
    Smacko
     
  2. BobK

    BobK

    7,671
    1,681
    Jan 5, 2010
    All signals switch over some period of time, and are therefore actually analog signals. In most cases, the rise time is not critical. Comparators (not opamps) are designed to switch quickly. Just use a comparator. Use positive feedback to avoid multiple triggering at the threshold.

    Bob
     
    SmackoJones likes this.
  3. SmackoJones

    SmackoJones

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    Jul 26, 2017
    You rock, Bob! Thank you for your help!!
     
  4. dorke

    dorke

    2,342
    665
    Jun 20, 2015
    "Can an analog signal into a digital triggering port damage the DAQ?"
    Yes, if it violates the min. or max. allowed input voltage of the DAQ.

    "Will this method work for my application? "
    Yes,In general .

    "Is there a better way of achieving my goal?"
    You need to specify what is the anolog signal voltage range.
    and what are the trigger points possible.
     
    SmackoJones likes this.
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