4.
Best Practice
In some circumstances user adopts a star
configuration in practical connection. The
termination resistors must be connected to the
two equipment that are farthest away from
each other, such as equipment 1# and 15# in
the following picture.
As the star configuration is not in conformity
with the requirements of RS485 standards,
problems such as signal reflections, lower anti-
interference performance arise when the
cables are long in the connection.
The reliability of control signals is decreased
with the phenomena that the dome does not
respond to or just responds at intervals to the
controller, or does continuous operation
without stop ( refer to following picture).
5. RS485
Trouble
Possible Cause
Solution
Dome can do
self-testing
but cannot
be controlled.
1. The address and
baud rate settings
of dome are
not in conformity
with those of
controller.
2. The + and -
connection of
RS485 Bus is
incorrect.
3. Wiring is not
fully seated.
4. There is
breakage in the
middle section of
the
RS485 Bus.
1. Change the
address and baud
rate of
controller or dome.
2. Correct the
connection.
3. Make sure the
connections are
fully
seated.
The dome
can be
controlled
but the
operation is
not smooth
1. The RS485 Bus
line is not in good
contact with
the connectors.
2. One wire of the
RS485 Bus is
broken.
3. The dome is very
far away from
controller.
4. There are too
many domes
connected in the
system.
1. Secure the
connection.
2. Replace RS485
Bus wires.
3. Add termination
resistors to the
system.
4. Install RS485
distributor.
EVC-TP-SO453ARW, EVC-TP-SO448AN
www.eurovideo-cctv.com
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