Figure 19 Digital Gateway Rs485 Connection Via Serial 2 To Dcs; Figure 20 Example For Rs485 Bus Termination And Biasing - ABB LVS Digital Manual

D CS FI ELDBU S
5.4.1.3. RS485
Allows multi drop topology with a maximum of 31 devices on the link. The maximum distance
according to the standard is 1000 meters (depending on communication speed

Figure 19 Digital Gateway RS485 connection via Serial 2 to DCS

5.4.1.4. Termination
The RS485 bus must be terminated at both ends.
The Digital Gateway does not provide an in-built MODBUS RTU termination for RS485 com-
munication; therefore, correct measures must be taken to connect termination to both ends
of the segment.

Figure 20 Example for RS485 bus termination and biasing:

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