Alarm Relay Sticking after motion detect

Discussion in 'Dahua' started by Kymadn, Sep 11, 2018.

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  1. Kymadn

    Kymadn Young grasshopper

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    I believe i have come up with a solution to isolate the camera I/O's. If this works all i would need is to put a few diodes on each camera and i can use the existing wiring and relay. This should at least stop the other cameras which are commoned together from sensing a contact close from a different camera.

    *Attached updated schematic*
     

    Attached Files:

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  2. TonyR

    TonyR IPCT Contributor

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    That should prevent the issue you described...for what it's worth, I'm looking at my hand-drawn sketch of the same thing, only diff is I used 1N4001 (1.0 Amp) diodes, was going to make it look nice and post it but you're on it, man! :headbang:

    Basically, the steering diodes create a n-input 'OR' gate (negative logic, low true) to drive the relay coil.
     
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  3. Kymadn

    Kymadn Young grasshopper

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    Thanks mate. I really hope this solves all my problems. A 1N4001 would probably be better. I just grabbed a 1N4004 because i already have a few. I have ordered 4 new cameras so i can test this setup on the bench before i head back to the job site to fix the issues.

    I will let you guys know how it goes. If anyone else has some feedback on this schematic i would love to hear it.
     
  4. J Sigmo

    J Sigmo Known around here

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    I've removed the superfluous content from my posts to this thread.

    Using isolation diodes to OR the signals will likely fix the problem regardless of whether the outputs are "open collector" or "push pull". So I can't see why this won't work just great!

    The 1N4004s are fine. The only difference in the specifications is the maximum reverse voltage rating. Having a "too high" max reverse voltage won't hurt a thing. And they cost almost exactly the same, at least in reasonable quantities from most vendors. So if I'm keeping a bunch of general purpose 1A diodes on hand, why not get the ones with the higher breakdown voltage?

    Your solution will almost surely work.

    Of course, being the inquisitive type, I'd love it if you do perform the bench tests I outlined above, with the 1000 ohm "load", if you have the time to play with it that way.

    Thanks!
     
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  5. Kymadn

    Kymadn Young grasshopper

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    Anyone know if you can turn off the second SMPT email alert which comes back after the alarm:

    Alarm Event: Motion DetectionStop
    Alarm Input Channel: 1
    Alarm Stop Time(D/M/Y H:M:S): 15/09/2018 00:04:26
    Alarm Device Name: LP1_CAM_4