26
Comply with the different model configured the suitable wireless USB adapter. (Each
model has its own USB adapter and the corresponding drive manual)
7. Appendix
7.1 RS485 Bus General Knowledge
●RS485 Bus General Character
According to RS485 industrial standards, RS485 Bus is of half-duplexes data
transmission cables
with characteristic impedance as 120. The maximum load capacity is 32 unit loads
(including main
controller and controller equipment)
Distance of RS485 bus transmission
While use the 0.56mm (24AWG) twisted cable as the communication, the farthest
distance it can reach as follow based on the different Baud rate
：
Baud rate
Max.distance
2400bps
1800M
4800bps
1200M
9600bps
800M
19200bps
600M
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.
。
●Connection and termination resistance
The RS485 standards require a daisy-chain connection between the equipment. There
must be termination resistance with 120 impedance at both ends of the connection (refer
to picture 4-1.1).Please refer to picture 4-
1.2 for simple connection But “D” should not
exceed 7m
。
………..
1# 2# 3# 4#
32#
Figure 4-1.1
A+
…………
D B-
A+ B-
…………
1# 2# 3# 4#
120
Ω
120
Ω
120
Ω