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How to drive DC cctv lens iris?

Discussion in 'Electronic Design' started by [email protected], Oct 14, 2007.

  1. Guest

    Can anyone point me to any information about driving the DC controlled
    iris of a cctv lens? These things have two coils, a driver and a
    damper. Voltage/current for both is normally supplied by the camera
    (standard 4 pin connector), and I guess there must be a standard but I
    can't find any information/specification about how to drive the two
    coils.
     
  2. Tim Wescott

    Tim Wescott Guest

    Two coils suggests a stepper motor to me, but I'm just guessing.

    --
    Tim Wescott
    Control systems and communications consulting
    http://www.wescottdesign.com

    Need to learn how to apply control theory in your embedded system?
    "Applied Control Theory for Embedded Systems" by Tim Wescott
    Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
     
  3. Guest

    It's defintely analog, I believe something like a meter movement.
     
  4. JosephKK

    JosephKK Guest

    posted to
    sci.electronics.design:
    It sounds like a voice coil type positioner with a feedback coil.
    Perhaps a lot like head positioners in disk drives.
     
  5. mpm

    mpm Guest

    Honestly, I just don't remember how this is done...
    It's been 10 years since I fooled with this, but as I recall, the
    solution was in fact pretty simple.

    Rather than guess, let me direct you to either Pelco or Panasonic.
    Both make CCTV gear and might have specs / white papers on their
    websites.
    Pelco also makes camera controllers (Panasonic: lenses and cameras).
    Either one should be able to help.

    Yes, there is a standard. (actually, there are a few, and probably
    some proprietary stuff out there too), but I recall -at the time- most
    of the commercial gear had the same basic requirements.

    Try Pelco first, they're smaller and you're less likely to get lost on
    their site.
    Good luck.
    -mpm
     
  6. mpm

    mpm Guest

    Flashback (??)
    I hit the enter key and then I remembered something...
    I think the auto-iris is wide open, and you just apply a voltage to
    close it down.

    I could be wrong about that, but something tells me that's what we
    did...?
    It was a long time ago, so check it before burning anything up. -mpm
     
  7. JosephKK

    JosephKK Guest

    mpm posted to sci.electronics.design:
    That is the general default, however you can order it with autoclose
    instead.
     
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