Dahua SD8A240VI-HNI, Installation Manual

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20
Figure 5-2
5.4 RS485 Bus FAQ
Phenomenon Possible Reasons Solution
Speed dome
can run self-
diagnosis but I
cannot control
it.

Host address(baud rate) and
speed dome address(baud rate)
are not match;

Positive and negative end of
RS485 Bus are misconnected;

Connection cable is loose
；

RS485 Bus connection are cut
off;

Modify host or speed dome setup
；

Switch RS485 positive end and
negative end
；

Fix connection cable firmly
；

Replace RS485 Bus.
I can control
the speed
dome but is not
smooth

RS485 Bus connection are not
good
；

One RS485 bus is off
；

The distance between host and
speed dome is too far
；

Parallel connected too much
speed domes.

Connect RS 485 Bus again
；

Replace RS485 Bus
；

Add terminal matching resistance
；

Add RS485 distributor.