RE: CCTV

["Brian G. Reynolds" <brian.g.reynolds@xxxxxxx>]

Hi Keith,
Thanks for your reply,


> -----Original Message-----
> From: Keith Doxey [mailto:ukha@xxxxxxx]
> Sent: 29 July 2001 14:12
> To: ukha_d@xxxxxxx
> Subject: RE: [ukha_d] CCTV
>
>
> 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.

Is there anyway to tell this? s  by dropping the voltage it generates more
heat? even just 3v?
is the opposite true as well? give it more voltage and it turns int  a
fridge..............
complicated this lecky stuff........


> > 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.

Could I therefore take a feed from the PC PSU and feed it t  all the
cameras
at the same time?
I was originally going to put an extension lead with all the PSU's plugged
int  it and use an appliance module to switch the extension lead but not
sure if it will all fit in the same case, heat might als  be a problem
although I could fit a high-speed cooling fan, I have another tray to try
just this.

> > 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  :-))

The royalty cheque is in the post :-)
Actually some months back I came across someone else who had done this
which
I liked the sound off but as Maplins never had the cases I did not pursue
it
but after seeing your job I decided to give it a go! good-un...


I have als  bought a 4U case to try and fit my Server int , but this needs
a
lot of thinking, something I am loathe to d  on a hot day like t day.

> > 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.)


What is a wall wart? is it just slang for all PSU's that plug int  the wall
and look hideous?

Would it be a good idea t  buy a PSU for this job?

> > 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.

What fuse should I use? presumably in line with the power cable in a
in-holder?


Sorry for all the questions but you guys are soooooooooooo clever!

B, sweating like a trooper.