> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On
Behalf
> Of Sarin Sukumar A
> Sent: 30 June 2011 08:53
> To: Microcontroller discussion list - Public.
> Subject: [EE] DC Auto Iris Control using PIC
>=20
> Hi everyone,
>=20
> I have an auto iris lens, it is galvanometric auto iris. My aim is to
> control the iris using PIC.
> Google dosn't provide much information, I am describing my
understanding ,
> please advice if there is any mistakes or anything is missing.
> galvanometric iris works with galvanic principle. the amount of
current
> causes the amount of iris open.
> there are two pins for drive (drive + and drive-), they can be used
for
> providing current to control the amount to open. Can I use PWM for
this?
> But there are two more pins (damp coil+ and damp coil-) I am clueless
> about
> this. What signal should i give to this pin? I guess they are for
playing
> the role of a permanent magnet in the galvanometer. is that correct?
> Should
> i give a constant dc voltage to this pin?
> or should i use pwm for this pin to control the current? can i control
the
> speed of iris open using them?
>=20
> I have attached the image of dc iris drive please advice.
> very thanks in advance
>=20

The damping coil provides velocity feedback for the circuit that
actually drives the iris.

Have a look at the following : http://bit.ly/jVDLLA

The url is huge so I have shortened it, but original is:

http://books.google.co.uk/books?id=3Dl8vgotpOJ1MC&pg=3DPA233&lpg=3DPA233&dq=
=3Dau
to+iris+damping+coil&source=3Dbl&ots=3D5CvRs4Fkcf&sig=3D1FdLjwY9MFsUrN-IUF-=
BkX
PHtwQ&hl=3Den&ei=3DzVQMTuWOEomj8QPurOiyDg&sa=3DX&oi=3Dbook_result&ct=3Dresu=
lt&resn
um=3D6&ved=3D0CDUQ6AEwBTgU#v=3Donepage&q=3Dauto%20iris%20damping%20coil&f=
=3Dfalse


=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
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--=20
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