Earthing
285
Mixed ground:
The mix ground consists of the feature of the one-point ground and
multiple-point ground. For example, the power in the system needs to use the one-point
ground mode while the radio frequency signal requires the multiple-point ground. So, you
can use the following figure to earth. For the direct current (DC), the capacitance is open
circuit and the circuit is one-point ground. For the radio frequency signal, the capacitance
is conducive and the circuit adopts multiple-point ground.
When connecting devices of huge size (the device physical dimension and connection cable is
big comparing with the wave path of existed interference), then there are possibility of
interference when the current goes through the chassis and cable. In this situation, the
interference circuit path usually lies in the system ground circuit.
When considering the earthing, you need to think about two aspects: One is the system
compatibility, and the other is the external interference coupling into the earth circuit, which
results in system error. For the external interference is not regular, it is not easy to resolve.
Appendix 7.3
Thunder Proof Ground Method in the Monitor
System
The monitor system shall have sound thunder proof earthing to guarantee personnel safety
and device safety.
The monitor system working ground resistance shall be less than 1Ω.
The thunder proof ground shall adopt the special ground cable from the monitor control
room to the ground object. The ground cable adopts copper insulation cable or wire and its
ground section shall be more than 20mm
2
.
The ground cable of the monitor system can not short circuit or mixed connected with the
strong alternative current cable.
For all the ground cables from the control room to the monitor system or ground cable of
Summary of Contents for Smart 1U
Page 1: ...DIGITAL VIDEO RECORDER User s Manual V1 0 0...
Page 30: ...Connecting Basics 20...
Page 80: ...Local Configurations 70 No Icon Description...
Page 181: ...Local Configurations 171 Select the Enable check boxes to enable IoT function See Figure 5 152...
Page 234: ...Local Configurations 224...
Page 280: ...Glossary 270 Abbreviations Full term VGA Video Graphics Array WAN Wide Area Network...
Page 298: ...Earthing 288...
