Problem with PIR

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  • Karam
    Automated Home Legend
    • Mar 2005
    • 863

    #16
    Ok so I'm scratching my head here. This then doesn't indicate a direct connection between the output and the remainder of the PIR - at least not a straightforward one. Yet some of your previous observations suggest something funny going on. Anyhow as a general guideline if you have any suspicions of connectivity between IDRANet 0V and the 0V of a different supply it is best avoided because 0V is a relative term meaning that noise currents can flow between the 0V connections of the different supplies. In other words better to use the IDRANet supply to provide power to the PIR or smoke detector or whatever if this is possible. Possible meaning that the device can handle up to 15V and that it does not draw too much current. For example the PIR unit consumes about 9mA so quite small relative to the maximum line budget of 1A, whereas if you had a device that consumed 100mA you may have to think more carefully about what else you are powering from that same line. In the case of C and NC labels, though in theory and for a mechanical relay it shouldn't make any difference, I'd go with C to 0V and NC to digital input on the digital input connector.
    Last edited by Karam; 10 February 2014, 10:04 AM.

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    • chris_j_hunter
      Automated Home Legend
      • Dec 2007
      • 1713

      #17
      original message mentioned their being several of the new ones - do they all behave the same ?
      Our self-build - going further with HA...

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      • chris_j_hunter
        Automated Home Legend
        • Dec 2007
        • 1713

        #18
        another thought - did you try resetting the module ?
        Our self-build - going further with HA...

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        • Karam
          Automated Home Legend
          • Mar 2005
          • 863

          #19
          It would seem that the problem was resolved by supplying the PIR from IDRANet power, but that some of the earlier observations have yet to be explained. For example the issue of the sense voltage only dropping to ~1.2V may have been explainable if an EOL resistance had been selected on the PIR, however the multimeter measurement showed the resistance changing between O.L and ~15ohms. If an EOL resistor were linked in then the latter would more likely be of the order of 2k. Could be that the link position was changed between multimeter resistance measurement and active use voltage sense measurement I suppose. But still leaves the question of how the PIR was seemingly powered with just the '+' terminal connected and later measurements didn't show an obvious path between the '-' terminal and the 0V conection on the output side.

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