RE: CCTV

["Keith Doxey" <ukha@xxxxxxx>]

Hi Brian,



> -----Original Message-----
> From: Brian G. Reynolds [mailto:brian.g.reynolds@xxxxxxx]

> I am in the process of connecting up my CCTV cameras and have notice
some
> are using 12v 300mA and some 15v 300mA power supplies, does it matter
if I
> plug the wrong one in the wrong camera?


Depends on the camera. If it has onboard voltage regulation then it should
be OK. If not you may kill it. Als  even if it has onboard voltage
regulation, dropping the extra voltage willl generate quite a bit more
heat.


> The reason I ask is that two of the cameras I have had for a few years
> connect straight int  a CCTV monitor @ 12v therefore have not got
> individual power supplies, but I have quite a few of the 15v supplies
s
> would like t  use these.

You say you are using the server PSU for the ASEL switcher, you could
possibly use it for the camera supply as well. Each camera only takes about
4 watts.

>
> I have yesterday, build the HV & expansion boards int  a 2U
> Maplin box

If it looks ANYTHING like the one I did for Mark you owe us both some
royalty fees  :-))

> I was going to fit Cat5 plugs ont  the ends of all the CCTV
> cameras and plug
> them int  CAT5 wall outlets then via a patch panel int  the ASEL box
which
> will als  supply the power t  run the cameras down the CAT5 cable, the
> question being is this alright to d  this?
>

I have had CCTV cameras working like this at work for 2 years now, the only
problem has been a couple of the PSU's failing due t  being on 24/7. I have
now replaces the individual wall warts with a Farnell SwitchMode Power
Supply "salvaged" from a bit of scrap kit. Some of the cameras
are over 100
metres from the switcher. (I am using KAT5 circuitry for the video though
not direct connection to the CAT5 cable.)


> At the moment I d  this to control/power the ASEL card and all
> seems well as
> it is a small amperage but d  not want to start on this with gusto if
the
> theory is wrong. I als  use the Server power supply to power the ASEL
as
> suggested by some bloke by the name of Phil....
>

No problem doing this as long as you fit fuses to protect the cable in the
event of a fault.

Keith