Athena 16C series, Руководство пользователя

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13
Digital
Communications
Option
This method allows bidirectional data transfer over a twisted pair cable. The twisted
pair cable is a transmission line; therefore, terminating resistors are required at the
most distant ends of the line to minimize reflections (typically 120 ohms at each end).
The RS485 circuit is fully optically isolated, eliminating ground loop problems. Parallel
drops from the transmission lines should be kept as short as possible; however, the
line may be daisy-chained at each controller. The polarity of the line is important and
each device will specify an “A” (+) and “B” (-) connection.
Figure 1a. Wiring diagram for
RS-232 digital communications.
Figure 1b. Wiring diagram for
RS-485 digital communications.
Note: Call factory for a
recommended RS485
converter.