Last Revised 05/09/2013
14
A popular way to power the domes is using our COMPOSITE VIDEO cable (or
shotgun as its also known) as this cable can carry the power to the dome and the video
signal back to the monitor or DVR.
Alternatively the COMBO cable also
provides the RS485 data cable.
Connecting the PTZ camera
A heavy duty multi-core cable is used for power, video, alarm and RS485
connections.
The power connection
The thick BLACK cable in the multi-core cable has a power jack socket and this is connected
to a 24vAC power supply. The distances for power cables are improved when using a 24vAC
camera but voltage drop over a long run may cause the camera to fail to initialise. Obviously
you can power the domes locally if you are able, which overcomes this issue.
The video connection
The thinner BLACK cable in the multi-core cable has a BNC connector which is the
“VIDEO-OUT” from the camera and goes to the monitor or “VIDEO-IN” of a DVR camera
input.
The RS485 data connection for telemetry
The Orange and Yellow pair of cores in the multi-core cable are the RS485 data cables. These
are the cores that carry the RS485 control signal to the dome from either the keyboard or the
DVR. The next section of the instructions gives more detail on how to connect the RS485
data. Please also read the RS485 WIRING METHODS & TIPS section towards the beginning
of these instructions.
RS485 connection
-
Connecting the Keypad or DVR to the Dome
.
The dome is controlled by an RS485 data signal that is given by
either a KEYPAD or a suitable DVR. This data signal tells the dome
to pan, tilt, zoom etc. It is important that you read the early section of
these instructions to understand the fundamental principle of RS485
cabling techniques so that you get it right.
RS485 has two cores, A and B or more commonly known as RS485 + (A) and RS485 – (B)
and if you get these two, the wrong away around, you will not be able to control the dome.
Sometimes installers get the connections right on one dome but not on the other and find only
one dome works. They then swap the wires around at the keyboard only to find out one dome
has now burst in to life and the other one now failed!! But they don’t put 2 + 2 together and
realise their mistake, that they have wired one dome different to the other. Take great care
getting these the right way around and make sure you wire each dome IDENTICALLY so
that if you have to swap the A & B lines over at the keyboard you know all domes are wired
the same!!
The PTZ640 series adopts the following RS485 convention:
ORANGE = RS485 + or A
YELLOW = RS485 – or B
