VEGA WHA-GW-WIRELESSHART GATEWAY - Manual (Page 28)

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Installation
3.4 Connecting to RS-485
The Gateway is equipped with a fully galvanic isolated RS-485 interface. The interface is
daisy-chain capable through its duplicated RS-485 terminal block.
A terminating resistor is integrated and may be switched on/off by using the corresponding
DIP switch inside the Gateway housing (see chapter 6.1) . It is also possible to switch on/off
the terminating resistor via software (see chapter 5.5.1).
If the RS-485 cable ends at the WirelessHART Gateway and is not routed to other devices
(no daisy-chain connection), activate the terminating resistor to ensure reliable RS-485
communication.
Figure 3.11RS-485 interfaces
Danger!
Explosion hazard in Zone 2 when operating powered Gateway
If the Gateway is installed in Zone 2 and connected to power, there is an explosion hazard
when operating DIP switches, buttons or connecting/disconnecting cables.
The operation of DIP switches/buttons and the connection/disconnection of any cables in
Zone 2 is only permitted in the absence of a hazardous atmosphere or if the device is
disconnected from power!
Note!
Keep in mind the location of the Modbus PLC or DCS. The maximum length of the cable
running from the Gateway to the PLC/DCS is 1200 m (at reduced communication speed).
Use shielded twisted pair (STP) cables only.
1 First RS-485 interface
2 Second RS-485 interface