Equipment Communication 19
4
Equipment Communication
The background PC software is able to communicate with the system according to three protocols (TCP/IP, RS485
and WIFI) for data exchange and remote management.
4.1
Access Control Networking Wires and Wiring
1)
RS485 communication wires are made of internationally accepted shielded twisted pairs (RVVSP), which prove
effective to prevent and shield interference.
2)
The power supply is 12V DC converted from 220V or PoE.
3)
The Wiegand readers use 6-core communication shielded wires (RVVSP 6×0.5mm) (usually there are 6-core,
8-core, and 10-core types available for users to select according to the ports) to reduce interference during
transmission.
4)
As an electronic lock has a big current, it generates strong interference signal during an action. To reduce the
effect of an electronic lock during an action on other elements, 4-core wires (RVVP 4×0.75mm
2
, two for a
power supply and two for a door sensor) are recommended.
5)
“EXT RS485” interface use 4-core communication shielded wires (RVVSP 4*0.5mm).
6)
Other control cables (like exit switches) are all made of 2-core wires (RVVSP 2×0.5mm
2
).
7)
Notes for wiring:
Signal wires (like network cables and RS485 wires) can neither run in parallel with nor share one casing
pipe with large-power electric wires (like electronic lock wires and power cables). If parallel wiring is
unavoidable for environmental reasons, the distance must be over 50cm.
Try to avoid use of any conductor with a connector during distribution. When a connector is indispensable,
it must be crimped or welded. No mechanical force can be applied to the joint or branch of conductors.
In a building, distribution lines must be installed horizontally or vertically. They should be protected in
casing pipes (like plastic or iron water pipes, to be selected according to the technical requirements of
indoor distribution). Metal hoses are applicable to ceiling wiring, but must be secure and good-looking.
Shielding measures and shielding connection: If the electromagnetic interference in the wring
environment is found strong in the survey before construction, it is necessary to consider shielding
protection for data cables when designing a construction scheme. Overall shielding protection is required
if there is a large radioactive interference source or wiring has to be parallel with a large-current power
supply on the construction site. Generally, shielding measures include: keeping a maximum distance from
any interference source, and using metal wiring troughs or galvanized metal water pipes to ensure reliable
grounding of the connection between the shielding layers of data cables and the metal troughs or pipes.
Note that a shielding enclosure can have a shielding effect only when it is grounded reliably.
Ground wire connection method: Reliable large-diameter ground wires in compliance with applicable
national standards are needed on the wiring site, and should be connected in a tree form to avoid DC loop.
These ground wires must be kept far away from lightning fields. No lightning conductor can serve as a
ground wire, and ensure there is no lightning current through any ground wire when there is lightning.
Metal wiring troughs and pipes must be connected continuously and reliably, and linked to ground wires
through large-diameter wires. The impedance of this section of wire cannot exceed 2ohm. The shielding
layer also must be connected reliably, and grounded at one end to guarantee uniform current direction.
The ground wire of the shielding layer must be connected through a large-diameter (not smaller than
2.5mm
2
) wire.
