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3 - HARDWARE DESCRIPTION
3.9.2 - RS485 wiring: 7-inch controller
The following diagrams illustrate possible RS485 wiring schemes
for 7-inch controllers.
The first wiring scheme is the best option (RECOMMENDED), but
the second or the third wiring can also be used.
No.1 RS485 wiring diagram (RECOMMENDED)
No. 2 RS485 wiring diagram (CORRECT)
No. 3 RS485 wiring diagram (CORRECT)
No. 4 RS485 wiring diagram (INCORRECT- Do not use!)
No. 5 RS485 wiring diagram (INCORRECT- Do not use!)
3.9.3 -
RS485: Daisy chain configuration
The following illustration shows proper 3-wire cable with a shield
in a daisy chain configuration.
B C
D
Legend
B
Shield
C
Keep shield continued
D
Connect shield to earth ground only at one point
End of Line Resistor: Termination is only needed when running at
bus at very high speed over long distances.
The speed of the bus and the cable distance determine whether
termination is needed. It is meant to balance the bus to minimize
the ringing that may be caused by fast signals and the inductance
of the cabling.
At 9600 baud, termination will have little or no effect on the bus.
