I'm building a Photonic Mast (fancy, newfangled periscope) for my kid's playhouse. I got this camera which has 36X optical zoom controlled by RS485 and this RS485 PTZ decoder board which (per my understanding) should be able to accept digital inputs (button presses, ex: zoom in P.B., pan left P.B.) and turn them into RS485 commands to a PTZ camera.

I don't need pan/tilt; just zoom & focus. The camera has what appears to be digital inputs for zoom/focus but might not be. I'm afraid to try them for fear they might not be. The camera has no separate [zoom in/zoom out] or [focus close/focus far] terminals; just a zoom terminal, focus terminal, and common terminal.



Likewise the decoder board has what appears to be inputs for focus, zoom, iris, but the inputs are not separated [focus far/focus near], [zoom in/zoom out], [iris open/iris close] as they are for [pan left/pan right] and [tilt up/tilt down].



Neither product came with a sufficient amount of documentation and I was unable to accomplish my goal using the board. I have accomplished my goal by disassembling the camera and soldering wires onto the legs of the PCB buttons on the back of the camera so this thread is mainly just to satisfy my burning curiosity about how this stuff is supposed to work. I have a strong feeling that these functions are pretty standard and anyone with CCTV camera experience would immediately know what they're looking at and wouldn't need documentation. I guess that's who I'm looking to talk to here; or anybody with half a clue.

Some documentation for other brands of cameras shows application of 8-9VDC external power in one polarity or the other, to zoom in/zoom out, but (in both cases, camera AND board) with only one terminal for zoom/focus/iris (+ common) I'm not sure how that's supposed to work. Plus the camera has its own internal power for the zoom lens motor so applying external voltage might be a problem.

And what's with the relays on the PCB for right/down/up/"LEET"/auto? Relays make me question if those are actually outputs, not inputs? and why are there no relays for the zoom/focus/iris terminals? What the heck is going on here?

 

Writing my thoughts down and reading them back to myself has the strange effect of helping me gain clarity. In reading what I just wrote, I think I had an epiphany. I'm now 90% sure that the board isn't meant to turn button presses into RS485 commands; it's meant to accept RS485 commands and turn them into digital outputs for the case where maybe you have designed your own PTZ gimbal and want to interface it with an existing CCTV system which is using RS485. (hence "DEcoder").

But I still don't get the zoom/focus/iris bits. How does zoom/focus/iris typically work on CCTV zoom lens?

 

I have zero knowledge about your camera but wonder if the movement controls could be PWM of some sort? For example, 0% and 100% duty cycles might correspond to movement extremes, be it zoom, focus or iris.

 

I have zero knowledge about your camera but wonder if the movement controls could be PWM of some sort? For example, 0% and 100% duty cycles might correspond to movement extremes, be it zoom, focus or iris.

That would be interesting but I doubt that is the case. I have not run across any hint of that kind of control scheme in my random readings on camera controls. And if that were the case (assuming the camera comes set up that way and there's an on-screen menu option to disable it) upon power-up, in the absence of a 50% duty cycle PWM signal to hold the lenses at present position, the zoom and focus would automatically begin to move to one extreme or the other, and I have not had that experience.

 

in the absence of a 50% duty cycle PWM signal to hold the lenses at present position, the zoom and focus would automatically begin to move to one extreme or the other, and I have not had that experience.

Well that experience knocks my theory on the head. It also rules out the control signal being a simple DC voltage level if a 'half-way' voltage isn't already built in.

 

Don't know if it will apply to your camera, but many times on things sold on Ebay and Amazon that don't come with good instructions, you can find better ones by Googling. Seems that a lot of stuff sold there is really a pirated item that the original company documents much better.

 

Don't know if it will apply to your camera, but many times on things sold on Ebay and Amazon that don't come with good instructions, you can find better ones by Googling. Seems that a lot of stuff sold there is really a pirated item that the original company documents much better.

Yeah I know what you mean and I googled but no luck. These seem to be China originals. They sell under many names and from several sellers on ebay/amazon/Alibaba but I haven't found the "original" OEM/seller.