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.
Two coils suggests a stepper motor to me, but I'm just guessing.
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It's defintely analog, I believe something like a meter movement.
snipped-for-privacy@gmail.com snipped-for-privacy@gmail.com 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.
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
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
mpm snipped-for-privacy@aol.com posted to sci.electronics.design:
That is the general default, however you can order it with autoclose instead.
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