HD-SDI High Speed Dome Camera
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safety requirements and must not short circuited with high voltage electricity net. When the system is grounded separately, the
impedance of down conductor should be less than 4 Ohms and the sectional area of down conductor should be greater than 25
square mm (refer to following picture).
Appendix II: The Cleaning Of Down Cover
：
Use soft dry cloth or the substitute to clean the inner and outer surfaces.
For hard contamination, use neutral detergent. Any cleanser for high grade furniture is applicable.
Appendix III: RS485 Bus Basic Knowledge
：
1. Characteristics of RS485 Bus
As specified by RS485 standards, RS485 Bus is of half-duplex data transmission cables with characteristic impedance as 120 Ohm.
The maximum load capacity is 32 unit loads (including main controller and controlled equipment).
2. Transmission distances of RS485 Bus
When user selects the 0.56mm (24AWG) twisted pair wires as data transmission cable, the maximum theoretical transmitting
distances are as follows:
Baud Rate
Transmission Distance (Max.)
2400bps
5,906ft (1800m)
4800bps
3,937ft (1200m)
9600bps
2,625ft (800m)
If user selects thinner cables, or installs the dome in an environment with strong electromagnetic interference, or connects lots of
equipment to the RS485 Bus, the maximum transmitting distance will be decreased. To increase the maximum transmitting
distance, do the contrary.
3. Connection and termination resistor
3-1 The RS485 standards require a daisy-chain connection between the equipment.
There must be termination resistors with 120 Ohm impedance at both ends of the connection (refer to following pictures).
