Dahua HAC-HFW1801C-A, Руководство пользователя

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centralized power supply
The usual problem with a centralized power supply is that obvious black stripes appear on the
device screen, interfering with display.
The principle of centralized power is as follows:
Centralized feeding principle
CAM1
CAM2 CAM3
CAM4
The power output of CAM4 has two paths, return path 1 and return path 2. Reflow 2 first flows
to CAM1 and then flows to the power supply from the power supply ground of CAM1. In this
way, the backflow of the power supply ground of CAM4 affects the video ground of CAM1,
resulting in interference streaks on the screen. CAM4 also interferes with CAM2 and CAM3.
Similarly, CAM1, CAM2, or CAM3 affects the other cameras as well as itself.
The main reason for centralized power interference is that the ground connection of the
camera's power supply is not isolated. To resolve this issue: Use dual power devices with
isolation from the power source ground; equip low power devices with electrical isolators to
block the return path 2. Use isolated power supplies for each channel or power the device
separately. These are the two recommended methods.
Connector water protection
HDCVI cameras need to be waterproof and well protected. Once installed, wrap the BNC
connector and power connector tightly with insulating or waterproof tape to prevent the
ingress of water and external electromotive forces. When a device with a metal casing is
installed on metal surfaces, such as elevators or buses, the metal casing should not be in
contact with the installation surface to prevent the ingress of water and external
electromotive forces.
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