K&R GT600-4T132G User Manual page 263

It is recommended to use an STP cable as the RS485 bus and use a twisted cable to
connect 485+ and 485-. Connect a matching terminal resistor of 120 Ω respectively at
both ends of the bus to prevent signal reflection. The RS485 bus allows connection of
a maximum of 128 nodes and the distance of each node branch must be smaller than
3 m. Connect the reference ground of all nodes together.
The connecting modes of multiple nodes are described as below:
Daisy chain connection mode
Recommended
Master Slave 1
Branching connection mode
Recommended
3 m
Master
Note
Distance from the bus to the node cannot exceed 3 m.
Star connection mode (prohibited)
Prohibited
RS485 bus
Slave 2
RS485 bus
3 m
Slave 1 Slave 2
Slave 1
Slave 2 Master
Slave 3
8. Peripherals and Options
. . .
Slave 3 Slave N
3 m
. . .
Slave 3
Slave 4
Slave 5
Slave 6
Slave N
8
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