Dahua SD6C230U-HNI - RS485 Bus FAQ

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Figure 8-2
8.4 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.