COP-USA AS20RS485 User Manual
Page 3
…
511
ON
ON
ON
ON
ON
ON
ON
ON
ON
Before the application of the Dome pan/tilt, the address codes should be set first
by DIP1 to DIP9 of SW1 on PCB in binary 8421 coding system, in which DIP1
means lower bit and the maximum address is 511. State ON of the
DIP
-
SWITCH
means
“1” while OFF means “0”. Some address codes of the
DIP
-
SWITCH
are set as above.
5. Selection of 120
Ω Terminal Resistor
The DIP-10 of SW1 is used to select 120
Ω
terminal resistor. In order to remove the
reflection of echo wave in communication circuit, you can connect a 120
Ω
terminal
resistor in parallel between 485+ and 485- of the Dome (set the selection bit of 120
Ω
terminal resistor at ON). The standard of RS485 industrial bus requires all equipment
should be connected in daisy-chain style and both ends should be connected with 120
Ω
terminal resistor (see Figure 5). The simplified connection can be done as Figure 6
but distance “D” couldn’t be larger than 7 meters.
120Ω
120Ω
1#
2#
3#
4#
32#
. . . . .
<Figure 5>
III
．Dimension: