Vega WHA-GW-WIRELESSHART GATEWAY Manuel d'utilisateur télécharger pdf (Page 28)

221981 2011-07

WHA-GW-*

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

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Vega WHA-GW-WIRELESSHART GATEWAY Manuel d'utilisateur Page 28