How to drive DC cctv lens iris?

[[email protected]]

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.

 

[Tim Wescott]

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.

--
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

 

[[email protected]]

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

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

 

[JosephKK]

[email protected] [email protected] posted to
sci.electronics.design:

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

It sounds like a voice coil type positioner with a feedback coil.
Perhaps a lot like head positioners in disk drives.

 

[mpm]

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.

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

 

[mpm]

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.

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

 

[JosephKK]

mpm [email protected] posted to sci.electronics.design:

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

That is the general default, however you can order it with autoclose
instead.