Black Box 422 Manual De Usuario
Page 15
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Chapter 3: Installation and Configuration
Table 3-1. Pull-up and pull-down
resistor settings.
Mode
PU Setting
PD Setting
RS-232
Always off
Always off
RS-422
Always off
Always off
RS-485
Always on
Always on
3.4.3 Line Termination
A 120-ohm resistor is across each RS-422/485 input. If multiple devices are
configured in an RS-485 network, only the devices on each end should have the
termination in place.
configured in an RS-485 network, only the devices on each end should have the
termination in place.
Termination configuration is software selectable for both full- and half-duplex
RS-485. By default, line termination is disabled, and this configuration can be set
by placing a check next to “Enable Termination” in the “RS-485 Advanced
Configuration” field, as shown in Figure 3-3.
RS-485. By default, line termination is disabled, and this configuration can be set
by placing a check next to “Enable Termination” in the “RS-485 Advanced
Configuration” field, as shown in Figure 3-3.
Figure 3-3. Enable Termination.