Qvis APOHD-PTZ20, Руководство пользователя

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In this situation, we recommend RS485 distributor. This device can turn a star type connection into the
connection that conforms to the RS485 bus industry standard, which can avoid the above mentioned problems
and enhance communication reliability. See Figure 10-2.
Figure 10-2
10.4 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) do not match;

Positive and negative end of
RS485 Bus are not connected
correctly;

Connection cable is loose
；

RS485 Bus connections 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 the
movement is
not smooth

RS485 Bus connections are
poor
；

One of the RS485 buses is
offline
；

The distance between host and
speed dome is too far
；

Too many speed domes are
connected in parallel.

Connect RS 485 Bus again
；

Replace RS485 Bus
；

Add terminal matching resistance
；

Add RS485 distributor.