5. USER INTERFACES
5.11.2
RS-485/422 Ports
The RS-485/422 ports can be powered using the internal 3.3 V supply or by connecting an
external power supply to the port connector. External or internal power is selected by jumpers
J2 and J3 on the RS-485 module daughter board. To use internal power, place jumpers J2
and J3 across pins 2 and 3. To select external power, jumpers J2 and J3 must be on pins 1
and 2.
Interface behavior of module Expansion port RS-485/RS-422 can be made by wiring
Jumpers J4, J5 and J6 on the RS-485 module select the mode of the port – either RS-485
or RS-422 mode. If RS485 is required, jumpers J4 and J5 must be connected and jumper J6
disconnected. If RS422 is required, jumpers J4 and J5 must be disconnected and jumper J6
connected. Jumper placement can be seen in the pictures below (RS-485 module is viewed
from the top).
Internal power supply should only be used in the event that it is not possible to provide an
external power supply. If internal power supply used, RS-485/422 port will not be galvanically
separated.
Figure 23: Jumper position for external power supply (left) and internal power supply (right)
Figure 24: Jumper position for RS-485 (left) and for RS-422 (right)
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