CCTV lens Control

[Rob Martin]

Has anyone ever used a pic to control a CCTV camera lens?

I have to use a CCTV camera controller to control a servo.
I'm led to believe that standard cctv camera lens are moved by 0-10.5Volt which I'm guessing I can read using an A/D then do some maths and send out a servo pulse.

has anyone ever played with CCTV camera lenses?

Rob

[mugwamp]

Rob, I do a lot of CCTV for my job. What exactly are you trying to control? Generally, the iris is controlled by the camera itself. For the older-type camera, that have a zoom lens connected to the camera body, the zoom function is controlled through simple relay closures as are the pan/tilt functions. The newer dome cameras usually use an ASCII stream over RS422 to control all the functions.

[Ioannis]

hi mugwamp,

is there a pdf with specs about the ASCII codes used in this kind of control?

I was asked to build a Dome Camera Controller, but was not able to find any standards (if any exists).

Thanks
Ioannis

[mugwamp]

Ioannis, I'n not aware of an industry-wide standard but different brands of cameras can generally be adapted to work on each others system. The first question would have to be--what brand of camera are you trying to control? We use both Pelco and Sensormatic at our airport but there's lots of other brands out there. Our switch is American Dynamics. Most of our cameras are controlled using ASCII streaming via Manchester but we're changing to RS422 for new installations. Most manufacturers make the control information available on their websites because they often have to interface with other systems like security and DVR.

[Ioannis]

Many thanks about your reply. Not sure which brand our clients are going to choose.

About network, is there any special reason to choose RS422 instead of RS485?

Ioannis

[mugwamp]

Ioannis, I'm not sure why most manufacturers picked RS422 over RS485 since they both can go a long distance but it seems to be standard for the major manufacturers. Originally, they all tried to use their own proprietary networks but then they started selling their own brand of dome cameras for other manufacturers systems. For instance, the Pelco camera now has small adapter boards for each different brand of CCTV switch. My suggestion is to get your clients a bit more nailed down on what they plan to do.

[Ioannis]

Thanks a lot.

Yes, sometimes I really am very "elastic" with my clients. Have to quit that habbit...

Regards,
Ioannis