Emerson Vission 20/20 Operation And Service Manual page 184

Appendix B • Vission 20/20 Application Procedures
Figure B-12. Serial Communication Ports on Single Board Computer
P12 = RS485 Serial Modbus RTU connector *
P14, P18 = USB Serial Modbus RTU connectors
P8 = Ethernet RJ45 connector
The 20/20 offers two solutions for serial communications. The fi rst option is connector P12 which uses tradi-
tional serial UART hardware. The second option uses the USB ports, P14 or P18. These ports require the use of
an inexpensive, industrial USB to RS422/RS485 convertor. Vilter can supply these, or you can purchase your own.
For serial communications, we recommend using the USB ports, fi rst because of the robustness of the USB ports.
They also offer increased speed. The third reason is that computer manufacturers are steering serial network us-
ers to move towards using the USB ports for serial communications.
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Vission 20/20 • Operation and Service Manual •Vilter/Emerson • 35391SC 2.0