IR Speed Dome User Manual
22
Figure A-2
RS485 Connection 1
Figure A-3
RS485 Connection 2
Problems in the Practical Application
Normally, users adopt star-shape connection method in construction, under this situation, the
terminal resistors must be connected between two farthest devices (as Figure A- 4, 1# and 15#), but
this connection method is not satisfy the requirement of the RS485 industry standard so that it will
lead to some problems such as signal reflection, anti-jamming ability decline when the devices are
faraway. At this time, the speed dome will be uncontrollable, or self-running, etc.
Figure A-4
Star Shape Connection
For such case, the best way is adding a RS485 distributor. This product can effectively change the
star-shape connection to which satisfies the requirement of RS485 industry standard, in order to
avoid those problems and improve the communication reliability.
