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Question about hall effect / floating signal

Discussion in 'General Electronics Discussion' started by Hdp160, Sep 11, 2016.

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  1. Hdp160

    Hdp160

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    Sep 11, 2016
    Hi I want to add a manual switch to isolate a rotary flow sensor. (I'm guessing hall effect?) To stop it reporting flow several times a day.

    Flow turbine sensor has 3 wires ... red (5v) black (gnd) and yellow (data pulses).

    Ideally the switch will be 1 to 1.5m from sensor and 1 to1.5m away from PCB.. currently the sensor and PCB are about 400mm apart.

    Please can someone advise the best way of going about this to avoid leaving the data line floating.

    Sorry for the simple question but this is not my usual area.
     
  2. Alec_t

    Alec_t

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    Jul 7, 2015
    A SPDT switch, with common as the PCB input, NC going to the sensor and NO going to one or other power rail (depending on what your PCB will accept as 'zero' flow?
     
  3. Hdp160

    Hdp160

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    0
    Sep 11, 2016
    Thanks very much, after I posted it occurred to me that the yellow wire which I refered to as data signal is probably more accurately a variable voltage returnIng from the flow (0v @no flow... +a few volts during flow) turbine and less likely to suffer from "spikes" so probably not requiring a pullup but probably pulldown.... so NC to ground do you think?
     
  4. Alec_t

    Alec_t

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    Jul 7, 2015
    Sounds right.
     
  5. Hdp160

    Hdp160

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    Sep 11, 2016
    Thanks :)
     
  6. Alec_t

    Alec_t

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    Jul 7, 2015
    By using the terms NC and NO I may have implied the switch had bias. That wasn't the intention. If the switch is manually controlled then NC and NO are interchangeable fo this application.
     
  7. Hdp160

    Hdp160

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    0
    Sep 11, 2016
    Ok thanks..
     
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