Cable length from box to device („Stubs“) has to be limited to 2m using connector boxes.
RS-485 bus serial wiring with connector boxes and connection cable
A direct RS-485 bus star wiring is not supported unless using a signal distributor (see below).
Improper RS-485 bus star wiring
A RS-485 signal distributor may be used to use a star wiring configuration.
Star wiring with RS-485 signal distributor
A RS-485 distributor can also be used to increase the maximum number of devices on the bus as well as the total range. Each distributor output provides another RS-485 bus. This allows each output to extend an additional 1200m, and it also enables the additional connection of 31 further devices to each output (the output itself represents one device).
The maximum system expandability depends on the RS-485 address range of the installed devices.
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