Vista PowerDome Series, Руководство по установке

Страница: 7 / 44

PowerDome Installation Manual Introduction
The 24VAC cable powers the PowerDome and the camera. To determine cable size, refer to the
Power Cable Size and Length subsection of the Introduction.
The RS485 control cable carries commands from the keypad to the PowerDome. An RS485
compatible shielded, two-conductor, twisted-pair cable is required. Recommended cable size is 22
gauge (0.64 mm).
Note: When using the UTP interface modules Vista recommends that you use only active receivers.
For UTC control, only a video coaxial cable is required.
1.4 P
OWER
R
EQUIREMENTS
CAUTION:
For optimal video performance, all PowerDomes must be powered from an isolated 24 VAC power
source—fused outputs are not adequate. Allowable voltage range is 20 to 28 V.
All domes require a 24 VAC power supply that provides isolated outputs to operate the domes’ pan/tilt
drive, camera, and heater/fan (if applicable). The total power requirement varies depending on the model
of the PowerDome.
Dome power requirements (at 24 VAC):
All domes without a heater/fan require 20 VA
7 inch domes with heater/fan require 55 VA
1.5 P
OWER
C
ABLE
S
IZE AND
L
ENGTH
It is important to choose the proper gauge of the cable that supplies 24 V to the PowerDome. An
inadequate gauge will cause a voltage drop resulting in improper operation.
Table 1 gives the recommended cable lengths of varying wire gauges for a PowerDome with a colour
camera. Note that the heater and fan reduces maximum cable length substantially.
Table 1. Maximum power cable lengths
Wire Gauge
All Domes
without Heater/Fan
(20 VA)
7 inch Domes
with Heater/Fan
(55 VA)
(AWG) (mm
2
) Feet Meters Feet Meters
10 2.60 1443 440 525 160
12 2.05 906 276 329 100
14 1.62 569 173 207 63
16 1.29 358 109 130 40
18 1.02 225 69 82 25
20 0.81 142 43 52 16
22 0.64 89 27 32 10
1040647A / July 2003 7