Installation
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4.3.3
DIP switch S2 for bias (RS-485 host/extension)
With the DIP switch S2, the RS-485 host interface (2.1./2.2) and the RS-485 extension interface
(2.3/2.4) can be biased when required, in order to achieve a significant improvement of
communication security.
DIP switch S2: RS-485 bias
1
2
3
4
Function
OFF
OFF
OFF
OFF Bias off (factory setting)
ON
ON
OFF
OFF Host bias
OFF
OFF
ON
ON Extension bias
ON
ON
ON
ON Host and extension bias
Table 2: DIP switch S2 configuration
In an RS-485 network, only one bias point is permitted. For this reason, leave the
switches in the OFF position if another device is already biasing the network.
Figure 6: DIP switch S2
4.4
Supply voltage connection
The auxiliary power (electrical connection) must be supplied using fixed wiring (not via a
connector), and is ducted through the lower right cable gland. Connect the power supply to
the provided terminal blocks (see Figure 1).
A(+)
RS-485
B(-)
+5V
GND
ON/OFF
ON/OFF
820
820
