GE Multilin D400, Инструкция по эксплуатации

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42 GE INFORMATION D400 SUBSTATION GATEWAY INSTRUCTION MANUAL
CHAPTER 3: SETTING UP COMMUNICATION CARDS
Switch SW3/SW4 configuration
Switches SW3 (for Channel 2 on TB1-6 through TB1-10) and SW4 (for Channel 1 on TB1-1
through TB1-5) contain ten DIP-switches that control RS-422 pull-up and pull-down
resistors for the differential data lines and provide line termination between the differential
data pairs. Each DIP-switch can be set to
ON or OFF to select the appropriate function for
the switch. That is, if all pins are set to ON , switch is ON. If all pins are set to OFF , switch is
OFF.
If RS-422 termination/pull-up is selected, the TX+ and RX+ signals have a 680 ohm pull-up
resistor, the TX- and RX- signals have a 680 ohm pull-down resistor, and the RX and TX
signals have a 120 ohm termination.
Figure 17: RS-485 Mode - 12 KOhm (Single Unit Load))
Figure 18: RS-422 120 Ohm Line Termination on TX and RX
Figure 19: RS-422 120 Ohm Line Termination with 680 Ohm Pull-Up and Pull-Down
Resistors
1 2 3
ON
4 5 6 7 8 9 0
1 2 3
ON
4 5 6 7 8 9 0
1 2 3
ON
4 5 6 7 8 9 0